CN102815901B - Ultralow-temperature high-performance concrete for railway construction in severe cold regions and preparation technique thereof - Google Patents

Abstract

The invention discloses an ultralow-temperature high-performance concrete for railway construction in severe cold regions and a preparation technique thereof. The concrete is prepared by evenly mixing cementing material, sand, gravel, high-efficiency water reducing agent, composite antifreezing agent and water, wherein the cementing material is prepared by evenly mixing cement and mineral admixture in a weight ratio of (15-20):(85-80); the water reducing rate of the high-efficiency water reducing agent is not less than 25%; the composite antifreezing agent comprises 30-35 wt% of nitrate, 30-33 wt% of organic compound, 0.5-1 wt% of calcium formate and the balance of water; the nitrate is calcium nitrate or calcium nitrite; and the organic compound is methanol or ethanol. The preparation technique comprises the following steps: 1. preparing the composite antifreezing agent; and 2. evenly mixing to obtain the ultralow-temperature high-performance concrete. The preparation technique disclosed by the invention is simple to operate and has the advantages of simple steps and favorable use effect; and the workability of concrete, and the mechanical properties and endurability after curingcan satisfy the design requirements.

Description

Severe cold area construction of railways ultralow-temperature high-performance concrete and preparation technology thereof

Technical field

The invention belongs to the high performance concrete preparing technical field, especially relate to a kind of severe cold area construction of railways ultralow-temperature high-performance concrete and preparation technology thereof.

Background technology

Civil engineering is positioned at the west and south, Heilongjiang Province before the Line for Passenger Transportation station, newly built railway Harbin to Qiqihar, the main climatic characteristics in area along the line is: 39.8 ℃ of Extreme Maximum Temperatures, the extreme lowest temperature-42.6 ℃, the coldest monthly mean temperature all is lower than-15 ℃, total track length 280.893km, the winter severe cold drying is very long, and the phase of stopping in winter reaches six months, and the soil maximum depth of freezing along the line is 1.89m～2.14m.Requirement according to the special construction period arrangement of present visitor and the Ministry of Railways, winter construction is essential, and winter high performance concrete control of construction quality and the control of construction quality of normal concrete be different, normal concrete only need to be considered the hydration heat problem of early strength and mass concrete, high performance concrete not only will be considered front two, also to consider later strength and endurance quality, high performance concrete (High performance concrete, be called for short HPC) be a kind of novel High Technique Concrete, be the concrete that adopts the modern concrete fabrication techniques on the basis that increases substantially the normal concrete performance.It for different purposes requirements, is guaranteed following performance focus: weather resistance, workability, suitability, intensity, volume stability and economy with the leading indicator of weather resistance as design.For this reason, the characteristics of high performance concrete in configuration are to adopt low water binder ratio, select high-quality raw material, and fine mineral admixture and the efficient additive of necessary admixture sufficient amount.At present, domesticly can use for reference without documents and materials at aspects such as severe cold area concreting in cold weather experiences.Whether affect later strength and endurance quality for the high performance concrete early strength, just, how final setting time to control, critical strength reaches how much to be unlikely to be subject to freeze injury etc. all be the problem of needs solution.Therefore, construction of railway project is significant from now on to instructing for research severe cold area construction of high-performance concrete.

Summary of the invention

Technical problem to be solved by this invention is for above-mentioned deficiency of the prior art, and the severe cold area construction of railways ultralow-temperature high-performance concrete that a kind of preparation process is easy, be applicable to ultra-low temperature surroundings construction and excellent property is provided.

For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of severe cold area construction of railways ultralow-temperature high-performance concrete, it is characterized in that: carry out even mix by gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water and form, the concrete unit weight of this ultralow-temperature high-performance is 2350kg/m ³～2450kg/m ³, and the concrete maximum water-cement ratio of described ultralow-temperature high-performance and sand coarse aggregate ratio, design with the mix proportion method of design all according to the design paper requirement that needs the construction concrete structure, and according to construction of railways; It is the high performance concrete of constructing under 0 ℃～-40 ℃ conditions that described ultralow-temperature high-performance concrete refers to be applicable to envrionment temperature;

Described gelling material is that the ratio of 15～20 ︰ 85～80 evenly mixes by cement and mineral admixture according to weight ratio;

The water-reducing rate of described high efficiency water reducing agent is not less than 25%, and the weight ratio of described high efficiency water reducing agent and described gelling material is 0.5 ︰, 100～1 ︰ 100;

The weight ratio of described compound antifreezer and described gelling material is 3 ︰, 100～6 ︰ 100; The composition of described compound antifreezer is by weight: nitrate 30%～35%, and organic compound 30%～33%, calcium formiate 0.5%～1%, surplus is water; Described nitrate is nitrocalcite or calcium nitrite, and described organic compound is methyl alcohol or ethanol.

Above-mentioned severe cold area construction of railways ultralow-temperature high-performance concrete, it is characterized in that: the concrete minimum gel material content of described ultralow-temperature high-performance and maximum unit water consumption, design with the mix proportion method of design all according to the design paper requirement that needs the construction concrete structure, and according to construction of railways.

Above-mentioned severe cold area construction of railways ultralow-temperature high-performance concrete is characterized in that: the concrete maximum water-cement ratio of described ultralow-temperature high-performance be 0.4 and its sand coarse aggregate ratio be 32%～44%.

Above-mentioned severe cold area construction of railways ultralow-temperature high-performance concrete is characterized in that: the concrete minimum gel material content of described ultralow-temperature high-performance is 360kg/m ³, the maximum unit water consumption is 165kg/m ³

Above-mentioned severe cold area construction of railways ultralow-temperature high-performance concrete is characterized in that: the concrete water-cement ratio of described ultralow-temperature high-performance is 0.26～0.4; In the described ultralow-temperature high-performance concrete, the weight ratio of sand and gelling material is 1.40～1.80.

Simultaneously, the invention also discloses a kind of processing step simple, realize convenient and the good ultralow-temperature high-performance concrete preparation technology of low, the prepared ultralow-temperature high-performance concrete performance of input cost, it is characterized in that this technique may further comprise the steps:

Step 1, compound antifreezer preparation, its preparation process is as follows:

Step 101, nitrate and calcium formiate preheating: with described nitrate and calcium formiate, be heated to respectively 40 ℃～70 ℃;

Step 102, evenly be mixed: with described nitrate and the calcium formiate after the preheating in water and the step 101, after mixing according to the design proportioning, make described compound antifreezer;

Step 2, even mix: after gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water carried out even mix according to the design proportioning, acquisition unit weight was 2350kg/m ³～2450kg/m ³The ultralow-temperature high-performance concrete.

Above-mentioned technique is characterized in that: when in the step 102 the described nitrate after the preheating in water and the step 101 and calcium formiate being mixed, adopt the circulation compound reactor to mix; Described circulation compound reactor comprises normal-pressure reaction kettle and the liquid circulation line that is installed on the described normal-pressure reaction kettle, on the described liquid circulation line recycle pump is housed, and described circulation compound reactor mixes evenly in the mode that described recycle pump pumps into circulating liquid in the described normal-pressure reaction kettle.

Above-mentioned technique is characterized in that: in the step 2 gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water are carried out adopting first heating installation that the water of the described ultralow-temperature high-performance the reinforcement of concrete of mix is heated to 50 ℃～70 ℃ before the even mix; Afterwards, again with sand, rubble, water, mineral admixture, cement and concrete admixture, enter even mix in the whipping device according to the design proportioning by first extremely rear respectively input, just obtain the described ultralow-temperature high-performance concrete that mix forms;

Wherein said concrete admixture comprises high efficiency water reducing agent and compound antifreezer.

Above-mentioned technique is characterized in that: when in the step 2 gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water being carried out even mix, the rotating speed of described whipping device is 23.5r/min ± 3r/min, and duration of mixing is no less than 120s.

Above-mentioned technique, it is characterized in that: when in the step 2 sand, rubble, water, mineral admixture, cement and concrete admixture being thrown in, the temperature of described sand, rubble, mineral admixture and cement all is not less than 0 ℃, and described high efficiency water reducing agent and compound antifreezer in the described concrete admixture are liquid state.

The present invention compared with prior art has the following advantages:

1, step of preparation process is simple, operation is simple and easy and it is convenient to realize, input cost is lower.

2, the ultralow-temperature high-performance concrete performance is good, no matter is concrete mechanical property and endurance quality after concrete workability and the sclerosis, all can reach design requirements.Simultaneously, this ultralow-temperature high-performance concrete can effectively be suitable for to concreting in cold-weather, and need during actual mix the concrete air content of ultralow-temperature high-performance is controlled at 3.0%～5.0%, the ultralow-temperature high-performance concrete of institute's mix can effectively be suitable for to the varying environment temperature such as 0 ℃～-40 ℃ in addition, and can effectively guarantee construction quality.

3, adopt ultralow-temperature high-performance mix proportion design process simple and optimize conveniently, only need the proportioning etc. of cement and mineral admixture in suitable water-cement ratio, sand coarse aggregate ratio, the gelling material just can be optimized the ultralow-temperature high-performance mix proportion.Simultaneously, the present invention has provided in the ultralow-temperature high-performance concrete each component to the rule that affects of the performances such as concrete 's air-containing, perviousness, crushing resistance, frost resistance, thereby the proportioning by respective components in the easy adjustment ultralow-temperature high-performance concrete, just can satisfy different design requirements.

4, ultralow-temperature high-performance concrete preparation technology is reasonable in design and workable, and the concrete structure amount that construction is finished is good.In the concrete mixing process, according to different temperature conditions, to measures such as starting material insulation, heating, improve concrete mix temperature and molding temperature, take the measures such as covering curing, boosting, improved the maintenance quality of concrete structure, thus further guaranteed on the technique construct and finish the quality of concrete structure.

5, each component proportion of the compound antifreezer that adopts is reasonable in design, easy to prepare and result of use is good, and the nitrate that adopts and nitrite are less on concrete weather resistance impact, and can effectively improve concrete endurance quality.During actual the use, according to design requirement, and in conjunction with function and the effectiveness of each component in the compound antifreezer, and by suitably adjusting the proportioning of each component in the compound antifreezer, just can prepare the compound antifreezer that meets design requirement and possess simultaneously diminishing, early strong, bleed and the effect such as antifreeze.The alkali-free of this compound antifreezer own, without chlorine, it is in the situation of Effective Raise early age strength of concrete, post-strength of concrete and endurance quality do not reduce, and can meet design requirement, and have overcome traditional antifreezing admixture to the unfavorable disadvantage of concrete durability.

6, have significant social and economic benefits, for the from now on winter construction of railway concrete engineering of severe cold area provides experience for reference, not only guaranteed construction speed, saved the energy, reduced cost, good application value is arranged.

In sum, step of preparation process of the present invention is simple, easy and simple to handle and input cost is low, result of use is good, no matter is concrete mechanical property and endurance quality after concrete workability and the sclerosis, all can reach design requirements.

Below by drawings and Examples, technical scheme of the present invention is described in further detail.

Description of drawings

Fig. 1 is the process flow diagram of the present invention when the ultralow-temperature high-performance concrete is prepared.

Embodiment

Embodiment 1

The ultralow-temperature high-performance concrete that the present invention is prepared carries out even mix by gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water and forms, and the concrete unit weight of this ultralow-temperature high-performance is 2350kg/m ³～2450kg/m ³, and the concrete maximum water-cement ratio of described ultralow-temperature high-performance and sand coarse aggregate ratio, design with the mix proportion method of design all according to the design paper requirement that needs the construction concrete structure, and according to construction of railways.

Described gelling material is that the ratio of 15～20 ︰ 85～80 evenly mixes by cement and mineral admixture according to weight ratio.During actual the use, described mineral admixture is coal dust ash or ground slag powder.In the present embodiment, described mineral admixture is the coal dust ash.

The water-reducing rate of described high efficiency water reducing agent is not less than 25%, and the weight ratio of described high efficiency water reducing agent and described gelling material is 0.5 ︰, 100～1 ︰ 100.

The weight ratio of described compound antifreezer and described gelling material is 3 ︰, 100～6 ︰ 100; The composition of described compound antifreezer is by weight: nitrate 30%～35%, and organic compound 30%～33%, calcium formiate 0.5%～1%, surplus is water; Described nitrate is nitrocalcite or calcium nitrite, and described organic compound is methyl alcohol or ethanol.

In the present embodiment, when the ultralow-temperature high-performance mix proportion is designed, the concrete minimum gel material content of ultralow-temperature high-performance and maximum unit water consumption, all according to the design paper requirement that needs the construction concrete structure, and design with the mix proportion method of design according to construction of railways, it is conventional railway construction mix proportion method of design well known to those skilled in the art.

When designing with the mix proportion method of design according to construction of railways, design according to (No. (2005) 157, iron construction) " railway concrete durability design of structure temporary provisions " and " design of common concrete proportioning rules " (JG J 55).

Wherein, water-cement ratio is the weight ratio of water and gelling material.The consumption S/ of sand coarse aggregate ratio SP=sand (the consumption S+ rubble consumption G of sand) * 100%, and sand coarse aggregate ratio is mass ratio.Minimum gel material content is the minimum amount of gelling material in the described ultralow-temperature high-performance concrete of every side, and its unit is kg/m ³Unit consumption of water is the concrete water consumption of the described ultralow-temperature high-performance of every side, and its unit is kg/m ³

When reality designs the ultralow-temperature high-performance mix proportion, after learning the concrete maximum water-cement ratio of ultralow-temperature high-performance, sand coarse aggregate ratio, minimum gel material content, unit consumption of water and unit weight, just can extrapolate the consumption of ultralow-temperature high-performance concrete medium sand and rubble.

During practice of construction, need the design paper of construction concrete structure to require usually to include various intensity and life requirement, reach cross section requirement, arrangement of reinforcement and the cement type of each member, the particle diameter of sand, the particle diameter of stone etc.In the present embodiment, needing the construction concrete structure is cushion cap, pier shaft, abutment body, top cap, pallet, basis, culvert body, pile cover or raft plate, and the construction environment temperature is 0 ℃～-40 ℃.

In the practice of construction process, the concrete maximum water-cement ratio of ultralow-temperature high-performance be 0.4 and its sand coarse aggregate ratio be 32%～44%.The concrete minimum gel material content of described ultralow-temperature high-performance is 360kg/m ³, the maximum unit water consumption is 165kg/m ³

When specifically the ultralow-temperature high-performance mix proportion being designed, the concrete water-cement ratio of ultralow-temperature high-performance is 0.26～0.4.In the described ultralow-temperature high-performance concrete, the weight ratio of sand and gelling material is 1.40～1.80.

In the present embodiment, the concrete water-cement ratio of described ultralow-temperature high-performance is 0.35, and sand coarse aggregate ratio is 35%, and the weight ratio of sand and gelling material is 1.5～1.6.Described gelling material is that the ratio of 82 ︰ 18 evenly mixes by cement and flyash according to weight ratio.The weight ratio of described compound antifreezer and described gelling material is 3 ︰ 100, and the weight ratio of described high efficiency water reducing agent and described gelling material is 0.5 ︰ 100.

During actual preparation, can be according to concrete needs, the weight ratio of weight ratio, described compound antifreezer and the described gelling material of weight ratio, sand and the gelling material of cement and flyash in water-cement ratio, sand coarse aggregate ratio, the described gelling material and the weight ratio of described high efficiency water reducing agent and described gelling material are adjusted accordingly.

In the present embodiment, used nitrate is nitrocalcite in the described compound antifreezer, and the composition of described compound antifreezer is by weight: nitrate 30%, and organic compound 33%, calcium formiate 0.75%, surplus is water.Described nitrate is nitrocalcite, and described organic compound is methyl alcohol or ethanol.

When reality is prepared described compound antifreezer, can according to concrete needs, adjust the consumption of described nitrate, organic compound, calcium formiate and water is corresponding.

The ultralow-temperature high-performance concrete preparation technology of a kind of severe cold area construction of railways as shown in Figure 1 may further comprise the steps:

Step 1, compound antifreezer preparation, its preparation process is as follows:

Step 101, nitrate and calcium formiate preheating: with described nitrate and calcium formiate, be heated to respectively 40 ℃～70 ℃.

In the present embodiment, when in the step 101 nitrate and calcium formiate being carried out preheating, described nitrate and calcium formiate are heated to respectively 50 ℃.During actual preparation, can be according to concrete needs, the preheating temperature of described nitrate and calcium formiate is adjusted accordingly.

Step 102, evenly be mixed: with described nitrate and the calcium formiate after the preheating in water and the step 101, after mixing according to the design proportioning, make described compound antifreezer.

Step 2, even mix: after gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water carried out even mix according to the design proportioning, acquisition unit weight was 2350kg/m ³～2450kg/m ³The ultralow-temperature high-performance concrete.

That is to say, gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water are carried out before the even mix, need to be prepared described compound antifreezer first, and described compound antifreezer evenly is mixed according to the design proportioning by nitrate, organic compound, calcium formiate and water and forms.

In the present embodiment, when the described nitrate after the preheating in water and the step 101 and calcium formiate are mixed, adopt the circulation compound reactor to mix.

Described circulation compound reactor comprises normal-pressure reaction kettle and the liquid circulation line that is installed on the described normal-pressure reaction kettle, on the described liquid circulation line recycle pump is housed, and described circulation compound reactor mixes evenly in the mode that described recycle pump pumps into circulating liquid in the described normal-pressure reaction kettle.During actual preparation, also can adopt the material mixing equipment of other type to mix.

In the present embodiment, the internal capacity of described normal-pressure reaction kettle is 10 tons, and the pumpage of described recycle pump is 60 tons/hour, and mixing time is no less than half hour.The power of motor of described recycle pump is 5.5 kilowatts.

In the actual fabrication process, in the step 2 gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water are carried out adopting first heating installation that the water of the described ultralow-temperature high-performance the reinforcement of concrete of mix is heated to 50 ℃～70 ℃ before the even mix; Afterwards, again with sand, rubble, water, flyash, cement and concrete admixture, enter even mix in the whipping device according to the design proportioning by first extremely rear respectively input, just obtain the described ultralow-temperature high-performance concrete that mix forms;

Wherein said concrete admixture comprises high efficiency water reducing agent and compound antifreezer.

In the present embodiment, gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water are carried out adopting first heating installation that the water of the described ultralow-temperature high-performance the reinforcement of concrete of mix is heated to 60 ℃ before the even mix.During actual preparation, can adjust accordingly according to the Heating temperature of concrete needs to the described ultralow-temperature high-performance concrete water of mix.

In addition, in the step 2 sand, rubble, water, flyash, cement and concrete admixture are carried out in the even mix process, the mixeding liquid temperature behind sand, rubble and the water mix is no more than 40 ℃.

In the present embodiment, the release sequence of each component is different from the normal temperature concrete during mix, need according to by first to after order sand, rubble, water, flyash, cement and concrete admixture are thrown in successively, mainly be to produce false set (cement contacts meeting generation false set with hot water more than 60 ℃) because the higher water of Heating temperature can be directly contact with cement moment.Thereby sand, rubble, water and flyash are thrown in cement after throwing in again, and churning time should increase 30s than normal temperature concrete, but should not be lower than 120s.

In the present embodiment, when sand, rubble, water, flyash, cement and concrete admixture are thrown in, the temperature of described sand, rubble, flyash and cement all is not less than 0 ℃, and described high efficiency water reducing agent and compound antifreezer in the described concrete admixture are liquid state.

That is to say, when sand, rubble, water, flyash, cement and concrete admixture are thrown in, should guarantee in described high efficiency water reducing agent and the compound antifreezer all without solid-state caking.

In the present embodiment, high efficiency water reducing agent and compound antifreezer should be stored in lagging material parcel or the storage tank that covers in, guarantee not freeze get final product, and the high efficiency water reducing agent and the compound antifreezer that are in liquid state generally should not heat.

In the actual fabrication process, before sand, rubble, water, flyash, cement and concrete admixture thrown in, when the temperature of described sand, rubble, flyash or cement is lower than 0 ℃, also need adopt heating installation respectively temperature to be lower than 0 ℃ described sand, rubble, flyash or cement and heat, and temperature after heating is no more than 30 ℃.

When having caking in described high efficiency water reducing agent or the compound antifreezer, also need adopt heating installation that described high efficiency water reducing agent or the compound antifreezer that has caking heated, until without till the caking.

In the present embodiment, the gelling material that is comprised of cement and flyash is stored in the outside hold-up vessel that wraps up with two-layer cotton pad, and two-layer cotton pad therebetween electric blanket, and the temperature of gelling material is controlled at about 0～10 ℃, the highest should not be above 40 ℃.

Described fine sand and rubble the day before yesterday must the charging canopies in construction, adopt caliduct geothermal heating method, and the temperature of fine sand and rubble must reach positive temperature before the mix, and the piece of freezing must not be arranged.

In addition, actual being prepared in the process, when described high efficiency water reducing agent and compound antifreezer were thrown in, one threw in or described high efficiency water reducing agent and compound antifreezer is thrown in simultaneously after one first; And one when throwing in after one first, and described high efficiency water reducing agent is thrown in prior to described compound antifreezer or described compound antifreezer is thrown in prior to described high efficiency water reducing agent and all can.

When reality was carried out even mix to gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water, the rotating speed of described whipping device was 23.5r/min ± 3r/min, and duration of mixing is no less than 120s.

In the present embodiment, when gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water are carried out even mix, adopt concrete agitation station to carry out mix, and described whipping device is the stirrer of described concrete agitation station.The model of described concrete agitation station is HZS 120G, and manufacturer is 31 heavy industrys, and the model of described whipping device is the JS2000 type, and motor power (output) is 37 kilowatts, and stirring velocity is 120 cubes m/hs, and the stirrer rotating speed is 23.5r/min.

During actual preparation, described high efficiency water reducing agent is polycarboxylic acid series high efficiency water reducing agent.In the present embodiment, described polycarboxylic acid series high efficiency water reducing agent is the standard type polycarboxylic acid series high efficiency water reducing agent, is specially the polycarboxylic acid series high efficiency water reducing agent that Sichuan superstar's admixture company limited produces.

In the actual fabrication process, in testing laboratory to after preparing the concrete air content of the ultralow-temperature high-performance that obtains, ultimate compression strength, perviousness, frost resistance etc. test.

When specifically testing, according to the blending method described in the step 1 ultralow-temperature high-performance concrete is carried out mix in testing laboratory and under room temperature, adopt the single horizontal shaft forced type concrete mixer of HJW60 to carry out mix herein, and mix is finished the measurement of the slump, air content and the moulding of ultralow-temperature high-performance concrete sample to be measured in the 5min after finishing.After the ultralow-temperature high-performance concrete sample to be measured moulding, precuring 4h～5h is left standstill in elder generation in room temperature environment after, be encased in the large-scale refrigerator-freezer that is cooled in advance design temperature and carry out maintenance, curing temperature maintains-14 ℃～-16 ℃, and rate of temperature fall is 3 ℃/h; Behind the negative temperature conservation 7d, take out from refrigerator-freezer and at room temperature leave standstill form removal behind 4h～5h, it is to be measured to 28d or the 56d to change standard curing room (20 ℃ ± 2 ℃) maintenance over to.

(1) ultralow-temperature high-performance concrete 's air-containing test:

The measuring method that adopts is according to GB/T 50080-2002 " Standard for test methods of properties of ordinary concrete mixture standard " prescriptive procedure, and adopt direct-reading type mixing wastewater with air gas content to measure, draw after measured that the concrete air content of prepared ultralow-temperature high-performance is 3.5% in the present embodiment.

In addition, in testing laboratory, also need the calcium formiate consumption in the used compound antifreezer of ultralow-temperature high-performance concrete is adjusted at 0～1.0wt%, and adopt direct-reading type mixing wastewater with air gas content that the concrete air content of prepared ultralow-temperature high-performance under the different calcium formiate consumptions is tested, test draws: because polycarboxylate high performance water-reducing agent contains certain bleed composition, so that the air content of normal concrete is very high, and the calcium formiate consumption is when being lower than 0.75wt%, the concrete air content minimum of prepared ultralow-temperature high-performance is 1.5% and maximum value only 2.4%, this the explanation nitrocalcite adding reduced the concrete air content of prepared ultralow-temperature high-performance, and the adding of calcium formiate so that the concrete air content of ultralow-temperature high-performance increase; And when the calcium formiate consumption in the compound antifreezer was 1wt%, the concrete air content of ultralow-temperature high-performance increased to 3.8%, had surpassed the air content 3.0% of normal concrete.

Simultaneously, also need flyash consumption (being the per-cent that flyash weight accounts for the gelling material gross weight) in the used gelling material of preparation ultralow-temperature high-performance concrete is adjusted, and adopt direct-reading type mixing wastewater with air gas content to measure, test draws, increase with flyash consumption in the gelling material, the concrete air content of prepared ultralow-temperature high-performance constantly reduces, this explanation, and flyash has adsorption than intensity to the bubble in the prepared ultralow-temperature high-performance concrete.

Thereby in the actual fabrication process, can prepare the concrete air content requirement of ultralow-temperature high-performance according to need, and in conjunction with calcium formiate consumption in the above-mentioned compound antifreezer on ultralow-temperature high-performance concrete (inside contains nitrocalcite) air content affect result and flyash to the adsorption of bubble in the ultralow-temperature high-performance concrete, calcium formiate consumption in the compound antifreezer is adjusted accordingly in 0.5%～1.0% scope; Simultaneously, flyash consumption in the gelling material is adjusted, specifically the weight ratio with cement in the gelling material and flyash adjusts accordingly in 88～78 ︰, 12～22 scopes.

(2) ultralow-temperature high-performance concrete tensile strength test:

When testing laboratory tests the concrete ultimate compression strength of ultralow-temperature high-performance, according to the ultralow-temperature high-performance concrete sample (100mm * 100mm * 100mm) test of GB/T50081-2002 " standard for test methods of mechanical properties of ordinary concrete " to made, YES-2000 type digital display hydraulic pressure trier is adopted in test, and maximum load capacity is 2000KN.In the present embodiment, the ultimate compression strength of prepared ultralow-temperature high-performance concrete sample was 40MPa when test drew " behind the negative temperature conservation 7d more positive temperature maintenance 28d ", and it is 80% that mark is supported compressive strength rate, and the benchmark compressive strength rate is 63%; The ultimate compression strength of prepared ultralow-temperature high-performance concrete sample is 50MPa when " behind the negative temperature conservation 7d more positive temperature maintenance 56d ", and it is 92% that mark is supported compressive strength rate, and the benchmark compressive strength rate surpasses 100%.

Wherein, the benchmark compressive strength rate is the ratio of ultimate compression strength with the ultimate compression strength of normal concrete of the ultralow-temperature high-performance concrete sample that draws of experimental test, mark is supported the ratio that compressive strength rate is ultimate compression strength with the concrete ultimate compression strength of normal curing of the ultralow-temperature high-performance concrete sample that draws of experimental test, and the concrete ultimate compression strength of normal curing herein is for carrying out the ultimate compression strength after the normal curing to the used ultralow-temperature high-performance concrete of preparation ultralow-temperature high-performance concrete sample.

And, also need the calcium formiate consumption in the used compound antifreezer of preparation ultralow-temperature high-performance concrete sample is adjusted at 0～1.0wt%, and employing YES-2000 type digital display hydraulic pressure trier, to made ultralow-temperature high-performance concrete sample at " negative temperature conservation 7d ", " behind the negative temperature conservation 7d more positive temperature maintenance 28d " tests with the ultimate compression strength in the different length of times such as " behind the negative temperature conservation 7d more positive temperature maintenance 56d ", draw after tested: " negative temperature conservation 7d " (wherein, d is day) and the ultimate compression strength of made ultralow-temperature high-performance concrete sample when " behind the negative temperature conservation 7d more positive temperature maintenance 28d ", along with the increase of calcium formiate consumption in the used compound antifreezer, slightly rising in the fluctuation up and down.And support compressive strength rate for benchmark compressive strength rate and the mark in " negative temperature conservation 7d " and " behind the negative temperature conservation 7d more positive temperature maintenance 28d " these two length of times, when not mixing calcium formiate in the used compound antifreezer, the foster compressive strength rate of the benchmark compressive strength rate of made ultralow-temperature high-performance concrete sample and mark is all minimum, wherein the benchmark compressive strength rate of ultralow-temperature high-performance concrete sample and mark are supported ultimate compression strength and are no more than 8% when " negative temperature conservation 7d ", and the benchmark compressive strength rate of ultralow-temperature high-performance concrete sample and mark are supported ultimate compression strength and be no more than 80% when " behind the negative temperature conservation 7d more positive temperature maintenance 28d "; But the ultimate compression strength of ultralow-temperature high-performance concrete sample when " behind the negative temperature conservation 7d more positive temperature maintenance 56d ", increase with calcium formiate consumption in the used compound antifreezer, slightly descending in the fluctuation up and down, and it is minimum when the calcium formiate consumption is 1.0wt% in used compound antifreezer that benchmark compressive strength rate that should the described ultralow-temperature high-performance concrete sample of section in the length of time and mark are supported compressive strength rate, and its mark is supported compressive strength rate and only had 87.85%.Make a general survey of the development and change of whole age concrete intensity, can obviously find out: when the calcium formiate consumption was 0.25wt% in the used compound antifreezer, the concrete mechanical property of prepared ultralow-temperature high-performance was best; When the calcium formiate consumption was 0.75wt% in the used compound antifreezer, the concrete mechanical property of prepared ultralow-temperature high-performance was taken second place; Be that the concrete crushing strength of 1wt% is all lower and do not mix calcium formiate and calcium formiate consumption in the used compound antifreezer.

Test result by above-mentioned ultralow-temperature high-performance concrete crushing strength can find out that also behind the adding nitrocalcite, the aquation of gelling material in the energy accelerate concrete is so that the concrete tensile strength of prepared ultralow-temperature high-performance increases in concrete.Wherein, nitrocalcite is good freezing protection effect not only, and nontoxicity, can improve the concrete hole gap structure, improves concrete density.Compare with calcium nitrite, the concrete workability of ultralow-temperature high-performance of adding nitrocalcite is more excellent, but it is less to add at low temperatures the concrete slump-loss of ultralow-temperature high-performance of nitrocalcite, can be used for pumping construction technique.But at low temperatures, the concrete strength increase of ultralow-temperature high-performance that adds nitrocalcite is slower, and the volume when effectively reducing freezing point is larger, and the later strength loss is also larger.

Simultaneously, also need flyash consumption (being the per-cent that flyash weight accounts for the gelling material gross weight) in the used gelling material of preparation ultralow-temperature high-performance concrete is adjusted, and employing YES-2000 type digital display hydraulic pressure trier, and according to GB/T 50081-2002 " standard for test methods of mechanical properties of ordinary concrete " tensile strength of made ultralow-temperature high-performance concrete sample is tested, test draws: when the flyash consumption was 15% in the used gelling material, the concrete ultimate compression strength of prepared ultralow-temperature high-performance was the highest; When the flyash consumption was 20% in the used gelling material, the concrete ultimate compression strength of prepared ultralow-temperature high-performance was taken second place; And the flyash consumption is 26.5wt% in the used gelling material.Thereby the flyash consumption should be controlled at 15%～20% in the used gelling material.

Thereby, in the actual fabrication process, can prepare the concrete tensile strength requirement of ultralow-temperature high-performance according to need, and in conjunction with flyash consumption in calcium formiate consumption in the above-mentioned compound antifreezer and the used gelling material on the impact of prepared ultralow-temperature high-performance concrete (inside contains nitrocalcite) tensile strength, calcium formiate consumption in the described compound antifreezer is adjusted accordingly in 0.5%～1.0% scope, and the weight ratio of cement and flyash in the described gelling material is adjusted accordingly in 88～78 ︰, 12～22 scopes.

In addition, for the flyash in the used gelling material, because it is active in cement clinker, particularly at the maintenance initial stage, pozzolanic reaction occurs hardly, therefore the flyash consumption is larger in the used gelling material, can reduce concrete early strength undoubtedly, and this effect then is very serious threat for negative temperature concrete.Thereby fly ash content should not surpass 20% in the used gelling material.

(3) ultralow-temperature high-performance concrete permeability test:

When testing laboratory tests with the concrete perviousness of ultralow-temperature high-performance, adopt the direct current measurement method to test.When adopting concrete electric weight method rapid detection perviousness, the water saturation circular sample cylinder test specimen of diameter 100mm, a high 50mm is placed on two ends to be equipped with in the container of liquid, it is 3% NaCl solution that container one end is filled mass concentration, and the other end is filled the NaOH solution that concentration is 0.3mol/L.Add the 60V direct current in the container simultaneously, negative pole links to each other with NaCl solution, and positive pole links to each other with NaOH solution.Wherein, electronegative chlorion will be to the positive pole migration from sample in the NaCl solution, and corresponding current potential just increases.Tested concrete perviousness is larger, and the chlorion of infiltration is just more, so electric current is just larger.

During actual test, adopt NEL-PEU type concrete charge pass determinator that the concrete perviousness of ultralow-temperature high-performance is tested, its test process is as follows: at first with ready ultralow-temperature high-performance concrete sample (after the side of 100mm * 100mm * 50mm) adopts the paraffin sealing, adopt again the water pretreatment of satisfying of the full wetting system of NEL-NVJ concrete intelligent vacuum, then test specimen is installed on the special-purpose anchor clamps with red and black electrodes, in the red jack one side battery jar of battery clamp, inject the NaOH solution of 0.3mol/L, implantation quality concentration is 3.0% NaCl solution in the black jack one side battery jar, after the solution injection is complete, with the wire exact connect ion on the corresponding position of determinator, open instrument, setting-up time, open channel, the every 15min of determinator gathers a secondary data, and the common 6h of need is finished in test.

In the present embodiment, the concrete displacement flux value of described ultralow-temperature high-performance was 1280C when test drew " behind the negative temperature conservation 7d more positive temperature maintenance 28d ", and the concrete displacement flux value of described ultralow-temperature high-performance is 730C when " behind the negative temperature conservation 7d more positive temperature maintenance 56d ".

And, also need the calcium formiate consumption in the used compound antifreezer of preparation ultralow-temperature high-performance concrete sample is adjusted at 0～1.0wt%, and adopt NEL-PEU type concrete charge pass determinator that the concrete perviousness of ultralow-temperature high-performance is tested, draw according to test result: along with calcium formiate consumption in the used compound antifreezer constantly increases in 0～1.0wt% scope, the concrete perviousness of prepared ultralow-temperature high-performance reduces first then to increase, wherein when the calcium formiate consumption is 0.75wt% in the used compound antifreezer, the concrete perviousness of prepared ultralow-temperature high-performance reaches Schwellenwert, especially when " behind the negative temperature conservation 7d more positive temperature maintenance 56d ", the concrete displacement flux value of prepared ultralow-temperature high-performance is 730C, and its displacement flux increment is negative value, and namely the concrete perviousness of prepared ultralow-temperature high-performance this moment has been lower than normal concrete.In addition, the displacement flux of the displacement flux when test draws " behind the negative temperature conservation 7d more positive temperature maintenance 56d " during than " behind the negative temperature conservation 7d more positive temperature maintenance 28d " obviously reduces a lot, and this is that the secondary reaction of hydration product of later stage flyash is filled due to the space.

Simultaneously, also need flyash consumption (being the per-cent that flyash weight accounts for the gelling material gross weight) in the used gelling material of preparation ultralow-temperature high-performance concrete is adjusted, and adopt NEL-PEU type concrete charge pass determinator that the tensile strength of made ultralow-temperature high-performance concrete sample is tested, test draws: with the increase of flyash consumption in the used gelling material, the perviousness of prepared ultralow-temperature high-performance concrete when " behind the negative temperature conservation 7d more positive temperature maintenance 28d " all increases gradually.Viewpoint according to Berry Malhotra, can reduce bonding between aggregate and the grout at the aquation initial stage as the flyash of gelling material, the moisture film of fly ash grain surface adsorption will make the zone of transition more porous that becomes, therefore under the negative temperature conservation condition, flyash in the used gelling material has negative effect to concrete perviousness, and this effect is serious all the more along with the increase of flyash consumption.Therefore, for the higher negative temperature concrete structure of life requirement, mixing of flyash should be prudent, mixes less or fly ash not, to guarantee the life-span of engineering as far as possible.

Thereby, in the actual fabrication process, can prepare the concrete perviousness requirement of ultralow-temperature high-performance according to need, and in conjunction with flyash consumption in calcium formiate consumption in the above-mentioned compound antifreezer and the used gelling material on the infiltrative impact of prepared ultralow-temperature high-performance concrete (inside contains nitrocalcite), calcium formiate consumption in the described compound antifreezer is adjusted accordingly in 0.5%～1.0% scope, and the weight ratio of cement and flyash in the described gelling material is adjusted accordingly in 88～78 ︰, 12～22 scopes.

(4) ultralow-temperature high-performance concrete antifreezing property testing:

According to the quick-freeze method of GB/T 50082-2009 " Standard for test methods of longterm performance and durability of ordinary concrete standard ", carry out the frost resistance test.The quick-freeze method is take U.S. ASTM C666 (A) method as the basis, and the freezing and melt all of ultralow-temperature high-performance concrete sample carried out in water.The concrete prism test specimen is carried out water freeze aqueous fusion, whole process needs to finish in 2h～4h.With concrete dynamic modulus of elasticity, mass loss rate and relative durability factor as evaluation index, with mass loss rate reach 5% or relative dynamic elastic modulus drop to 60% threshold value as concrete through freeze-thaw test, and regulation with relative dynamic elastic modulus drop to 60% or the freezing-thawing cycles of mass loss when reaching 5% as concrete freeze proof label, estimate concrete frost resistance with this.

(100mm * 100mm * 400mm) carry out fast freeze-thaw test is-17 ℃～8 ℃ from freezing to its center range of temperature of thawing end of a period, and whole Circulation calendar is through 3h～4h to the concrete prism test specimen to adopt TDR-1 concrete fast freeze-thaw test equipment.Per 25 freeze-thaw cycle are made one-shot measurement, until that concrete dynamic modulus of elasticity loss is down to is original 60% below or mass loss when reaching 5%, and the test termination.Dynamic modulus of elasticity and relative dynamic elastic modulus adopt NM-4B nonmetal ultrasonic detection analyser to test post analysis and draw.In the present embodiment, behind 225 freeze-thaw cycle, the mass loss rate of ultralow-temperature high-performance concrete sample is 3.5%, and relative dynamic elastic modulus drops to 57%, and test specimen can stand 200 times～225 times freeze-thaw cycle destruction.

And, also need the calcium formiate consumption in the used compound antifreezer of preparation ultralow-temperature high-performance concrete sample is adjusted at 0～1.0wt%, and adopt above-mentioned antifreezing test method that the frost resistance of prepared ultralow-temperature high-performance concrete sample is tested, test result is as follows: for the ultralow-temperature high-performance concrete that inside is added with nitrocalcite, no matter the calcium formiate consumption is arbitrary value in 0～1.0wt% scope in the used compound antifreezer, when test specimen reaches destruction, its mass loss does not all surpass 5%, and relative dynamic elastic modulus drops to below 60%, that is to say ultralow-temperature high-performance concrete that inside is added with nitrocalcite in standing the freeze-thaw cycle destructive process, the outside spalling damage of inner spalling damage is even more serious.Similar to perviousness, the inside of not mixing calcium formiate and calcium formiate consumption and be 1wt% is added with the ultralow-temperature high-performance concrete of nitrocalcite, in the freeze-thaw cycle process mass loss maximum, frost resistance is also the poorest.From the situation of peeling off on surface, mixing calcium formiate has certain restraining effect to the freezing-thawing damage of concrete surface, but along with the increase of calcium formiate consumption, this restraining effect weakens gradually; Degree of impairment internally, except the ultralow-temperature high-performance concrete of not mixing calcium formiate, other curves are more level and smooth, the phenomenon of bursting apart do not occur, and inside concrete evenly destroys.

Because concrete freeze-thaw damage comes from the inner swelling pressure that produce, should analyze the bulging force that causes the ultralow-temperature high-performance concrete destruction is because the diffusion of water has caused the volume growth of the ice of less quantity, the diffusion of water is because osmotic pressure produces, and osmotic pressure then is owing to do not freeze due to the increase of water intermediate ion concentration.

In addition, the oneself factor that affects ultralow-temperature high-performance concrete frost resistance quality mainly is concrete degree of compactness and internal pore structure.And pore structure is the major cause that affects this concrete frost resistance, the a small amount of calcium formiate of admixture is not enough to guarantee that the pore structure when the ultralow-temperature high-performance concrete hardens suffers freezing and destroys under subzero temperature, communicating aperture increases in the rear concrete of its sclerosis and the excessive calcium formiate of admixture makes, two kinds of effects interlaced is so that concrete pore structure is complicated and changeable.Thereby reply calcium formiate consumption accurately limits.

Simultaneously, also need flyash consumption (being the per-cent that flyash weight accounts for the gelling material gross weight) in the used gelling material of preparation ultralow-temperature high-performance concrete is adjusted, and tackle mutually the concrete frost resistance of prepared ultralow-temperature high-performance and test, test draws: flyash has a great impact the frost resistance of negative temperature concrete, with the increase of flyash consumption in the gelling material, the concrete frost resistance of prepared ultralow-temperature high-performance obviously reduces.Wherein, the flyash consumption is 10% in the gelling material, and it is best that inside is added with the concrete frost resistance of ultralow-temperature high-performance of nitrocalcite, and it still is higher than 60% with Young's modulus relatively behind 300 freeze-thaw cycle, but its mass loss is also maximum, behind 300 freeze-thaw cycle near 5%.

Flyash to the unfavorable factor of negative temperature concrete mainly from two aspects: at first, the introducing of flyash can affect concrete bubble structure, in the Concrete process, thinner fly ash grain usually can adsorb air entrapment agent molecule (containing the bleed composition in the polycarboxylate water-reducer), in the situation of identical bleed composition volume, the concrete air bubble content of ultralow-temperature high-performance will be reduced; Secondly, the activity of flyash is far away from cement, extremely slow at maintenance initial stage hydration reaction, especially under negative temperature conservation, flyash equivalent replaces cement, not only can postpone concrete and reach freeze proof critical strength, and make to contain in the concrete more and can freeze the water yield, make inside concrete produce larger ice crystal stress, destroy concrete structure.Although to the maintenance later stage, the secondary hydration product of flyash has some improvement to the pore structure of inside concrete, the moulding of concrete internal structure, it improves DeGrain.

Thereby, in the actual fabrication process, can prepare the concrete frost resistance requirement of ultralow-temperature high-performance according to need, and in conjunction with flyash consumption in calcium formiate consumption in the above-mentioned compound antifreezer and the used gelling material on the impact of prepared ultralow-temperature high-performance concrete (inside contains nitrocalcite) frost resistance, calcium formiate consumption in the described compound antifreezer is adjusted accordingly in 0.5%～1.0% scope, and the weight ratio of cement and flyash in the described gelling material is adjusted accordingly in 88～78 ︰, 12～22 scopes.

In sum, be added with the ultralow-temperature high-performance concrete of nitrocalcite for inside, the nitrocalcite that adds can reduce concrete air content, and being added in of calcium formiate increased the concrete air content of ultralow-temperature high-performance to a certain extent, but the increase along with the calcium formiate consumption, its air content slightly reduces, and when the calcium formiate consumption was 1wt%, air content increased to 3.8%; With the increase of calcium formiate consumption, the concrete ultimate compression strength of ultralow-temperature high-performance fluctuates to some extent, but the calcium formiate consumption is when being 0.75wt%, and concrete mechanical property is comparatively desirable; With the increase of calcium formiate consumption, after reducing first, the concrete perviousness of ultralow-temperature high-performance raises again; In standing the freeze-thaw cycle destructive process, it is even more serious that the spalling of test specimen inside damages outside spalling damage, and be inner evenly destruction in the freeze-thaw cycle process.

Be added with the ultralow-temperature high-performance concrete of nitrocalcite for inside, along with the increase of flyash consumption in the gelling material, the concrete air content of ultralow-temperature high-performance obviously reduces; The flyash consumption is 20% when following in the gelling material, and the concrete early strength function of ultralow-temperature high-performance is more remarkable; Under the negative temperature conservation condition, flyash has disadvantageous effect to the concrete perviousness of ultralow-temperature high-performance, and influence degree increases along with the increase of flyash consumption.Compound antifreezer that the present invention adopts has not only been avoided the detrimental action of part inorganic salt to concrete frost resistance, and by adjusting its inner each amounts of components, also can increase to the concrete frost resistance of ultralow-temperature high-performance.

When reality was prepared the ultralow-temperature high-performance concrete, the cement that adopts was 42.5 grades low alkali ordinary Portland cements, alkali content 0.59%, and chloride ion content 0.003%, other technical indicator meets the regulation of [2009] No. 152 files of iron construction.The water demand ratio of the flyash that adopts is not more than 95%, alkali content 2.10%, and chloride ion content 0.003%, all the other technical indicators meet the regulation of [2009] No. 152 files of iron construction.The river sand that adopts is the river sand of 5 constant virtues La Linhe, fineness modulus 2.6～2.9, and silt content 1.0%～1.5%, chloride ion content 0.0001%, active without potential alkali reaction, all the other technical indicators meet [2009] No. 152 files specify of iron construction.The rubble that adopts is that limestone gravel is produced in Yuquan, parent rock ultimate compression strength is 96MPa, particle diameter is 5～31.5mm, pin, platy shaped particle content are 5%～7%, silt content is below 0.5%, chloride ion content 0.0001%, without potential alkali active reaction aggregate, all the other technical indicators all meet the specified requirement of [2009] No. 152 files of iron construction.The high efficiency water reducing agent that adopts is the standard type polycarboxylic acid series high efficiency water reducing agent, alkali content 2.64%, and sodium sulfate 1.5%, chloride ion content 0.12%, all the other technical indicators meet [2009] No. 152 files specify of iron construction.The water that adopts is mixing water, alkali content 0.04677%, sodium sulfate 1.5%, chloride ion content 0.00293%.In the actual fabrication process, also can adopt the cement of other label and river sand, the rubble in other place of production.

When reality designs described ultralow-temperature high-performance mix proportion, need improve a strength grade according to code requirement, for high performance concrete, as long as measures is guaranteed, do not need to improve the intensity intensity level, still can guarantee the sclerosis quality of high performance for concrete structure.After determining optimum mix proportion, effectively control concrete coagulating time, guarantee that concrete can reach more than 40% of design strength (critical strength before requirement is endured cold) in 48h, 56d mechanical performance of concrete and endurance quality reach design requirements.

Railway high performance concrete design concept is the high-durability energy, the realization of high-durability energy need to be mixed high efficiency water reducing agent and flyash, the major function of flyash in concrete is to improve the interface structure of cement slurry and aggregate, replace a certain amount of cement, make the speed that produces hydration heat delay, prolong concrete time of coagulation, participate in the pore of aquation fill concrete, improve impervious, reduce folk prescription concrete harmful substance contents, energy establishment alkali-aggregate reaction, but early age strength of concrete is on the low side to some extent.

Frost-resistant concrete is general only to need to consider that early strength reaches certain value and gets final product, but early strength concrete is larger on the later strength impact, normal concrete need to improve a strength grade and just can meet design requirement, the high-performance frost-resistant concrete not only requires early strength high, and the growth of later strength can not be subject to large impact, otherwise can't satisfy life requirement.Flyash plays retarding action to the concrete early hydration, this is contradiction to the demanding frost-resistant concrete of early strength, and flyash is one of high performance concrete quality principal security condition, increase requirement in order to satisfy antifreeze high performance concrete early strength, make it not be subject to low temperature freezing-disaster under certain condition, and the later strength growth is not subject to large impact, and indices must reach the high performance concrete specification of quality.

Find that through test the consumption of compound antifreezer not only directly affects concrete time of coagulation, also concrete mechanical property and endurance quality is produced great effect.As can be seen from the test results, the consumption of compound antifreezer should be controlled at the weight percent of 3%～4%(and gelling material) be advisable, the impact of the main critical temperature of considering to endure cold, determining of critical strength is definite according to envrionment temperature, generally speaking, require critical strength to reach 40% of design strength in the time of-15 ℃ and just can satisfy the critical strength requirement of enduring cold, and-20 ℃ critical strength should be brought up to and is advisable more than 50%, can improve like this quality guarantee rate of concrete structure, reduce the risk of enduring cold.But early strength is too high, and is larger on post-strength of concrete impact, and on the impact of weather resistance also clearly, therefore, the compound antifreezer consumption should be controlled at one comparatively reasonably in the scope.

Mixing the flyash master is in order to reduce hydration heat, delay concrete time of coagulation, improve workability of concrete, reduce concrete shrinkage, to improve concrete anti-permeability performance etc.But it is very fast that the concrete of winter construction needs early strength to increase, and the presetting period must be done sth. in advance by a relatively large margin, and this need to mix compound antifreezer and realize, this contradicts with fly ash.If fly ash not, concrete can not satisfy high performance requirement, its major cause is: the one, and the folk prescription higher alkali content surpasses required standard, and the 2nd, to mix merely early-strength type antifreezing admixture late strength of concrete and had a strong impact on, endurance quality can not meet the demands.Therefore, in order to reach should early strength high, can not produce great effect to later strength again, but also must satisfy the intrinsic technical requirements of high performance concrete, must regulate the concrete property indices of ultralow-temperature high-performance with flyash.

When transporting after described ultralow-temperature high-performance concrete preparation is finished, the concrete delivery truck outside that transport point is used must be incubated with the lagging material parcel, and guarantee the coast is clear in transportation, dead time behind transportation and the arrival cast place should not surpass 60min, prevent that thermosteresis is excessive, when envrionment temperature was lower than-30 ℃, described ultralow-temperature high-performance is concrete to be gone out the tank temperature and should not be lower than 20 ℃.

Embodiment 2

In the present embodiment, the ultralow-temperature high-performance concrete of institute's mix is as different from Example 1: the concrete water-cement ratio of described ultralow-temperature high-performance is 0.3, the weight ratio of sand and gelling material is 1.4～1.5, sand coarse aggregate ratio is 32%, the weight ratio of cement and flyash is 88 ︰ 12 in the gelling material, the weight ratio of compound antifreezer and gelling material is 4 ︰ 100, and the weight ratio of high efficiency water reducing agent and gelling material is 0.8 ︰ 100; The compound antifreezer that adopts is as different from Example 1: the composition of described compound antifreezer is by weight: nitrate 35%, and organic compound 30%, calcium formiate 0.5%, surplus is water.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

Embodiment 3

In the present embodiment, the ultralow-temperature high-performance concrete of institute's mix is as different from Example 1: the concrete water-cement ratio of described ultralow-temperature high-performance is 0.4, the weight ratio of sand and gelling material is 1.7～1.8, sand coarse aggregate ratio is 38%, the weight ratio of cement and flyash is 78 ︰ 22 in the gelling material, the weight ratio of compound antifreezer and gelling material is 5 ︰ 100, and the weight ratio of high efficiency water reducing agent and gelling material is 1 ︰ 100; The compound antifreezer that adopts as different from Example 1: the composition of described compound antifreezer is by weight: nitrate 32%, organic compound 32%, calcium formiate 0.8%, surplus is water.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

Embodiment 4

In the present embodiment, the ultralow-temperature high-performance concrete of institute's mix is as different from Example 1: the concrete water-cement ratio of ultralow-temperature high-performance is 0.32, the weight ratio of sand and gelling material is 1.5～1.6, sand coarse aggregate ratio is 40%, the weight ratio of cement and flyash is 85 ︰ 15 in the gelling material, the weight ratio of compound antifreezer and gelling material is 3.5 ︰ 100, and the weight ratio of high efficiency water reducing agent and gelling material is 0.7 ︰ 100; The compound antifreezer that adopts is as different from Example 1: the composition of described compound antifreezer is by weight: nitrate 34%, and organic compound 32%, calcium formiate 1%, surplus is water.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

Embodiment 5

In the present embodiment, the ultralow-temperature high-performance concrete of institute's mix is as different from Example 1: the concrete water-cement ratio of described ultralow-temperature high-performance is 0.26, the weight ratio of sand and gelling material is 1.5～1.6, sand coarse aggregate ratio is 44%, the weight ratio of cement and flyash is 84 ︰ 16 in the gelling material, the weight ratio of compound antifreezer and gelling material is 6 ︰ 100, and the weight ratio of high efficiency water reducing agent and gelling material is 0.75 ︰ 100; The compound antifreezer that adopts is as different from Example 1: the composition of described compound antifreezer is by weight: nitrate 34%, and organic compound 32%, calcium formiate 0.65%, surplus is water.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

Embodiment 6

In the present embodiment, the ultralow-temperature high-performance concrete of institute's mix is as different from Example 1: the concrete water-cement ratio of ultralow-temperature high-performance is 0.394, the weight ratio of sand and gelling material is 1.75, sand coarse aggregate ratio is 40%, the weight ratio of cement and flyash is 331 ︰ 85 in the gelling material, the weight ratio of compound antifreezer and gelling material is 4 ︰ 100, the weight ratio of high efficiency water reducing agent and gelling material is 1 ︰ 100, it is C35 that mix forms the concrete strength grade of ultralow-temperature high-performance, and the slump is 160mm～180mm.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

Embodiment 7

In the present embodiment, the ultralow-temperature high-performance concrete of institute's mix is as different from Example 1: the concrete water-cement ratio of ultralow-temperature high-performance is 0.334, the weight ratio of sand and gelling material is 1.637, sand coarse aggregate ratio is 38.8%, the weight ratio of cement and flyash is 340 ︰ 90 in the gelling material, the weight ratio of compound antifreezer and gelling material is 4 ︰ 100, the weight ratio of high efficiency water reducing agent and gelling material is 1 ︰ 100, it is C40 that mix forms the concrete strength grade of ultralow-temperature high-performance, and the slump is 160mm～180mm.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

Embodiment 8

In the present embodiment, the ultralow-temperature high-performance concrete of institute's mix is as different from Example 1: the concrete water-cement ratio of ultralow-temperature high-performance is 0.324, the weight ratio of sand and gelling material is 1.546, sand coarse aggregate ratio is 37.9%, the weight ratio of cement and flyash is 346 ︰ 95 in the gelling material, the weight ratio of compound antifreezer and gelling material is 4 ︰ 100, the weight ratio of high efficiency water reducing agent and gelling material is 1 ︰ 100, it is C45 that mix forms the concrete strength grade of ultralow-temperature high-performance, and the slump is 160mm～180mm.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

Embodiment 9

In the present embodiment, the ultralow-temperature high-performance concrete of institute's mix as different from Example 1: the mineral admixture in the described gelling material is ground slag powder.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

Embodiment 10

In the present embodiment, in the step 1 the compound antifreezer that adopts as different from Example 1: the composition of described compound antifreezer is by weight: nitrate 30%, organic compound 33%, calcium formiate 0.85%, surplus is water.Described nitrate is calcium nitrite, and organic compound is methyl alcohol or ethanol.

In the present embodiment, concrete all the other component proportions of the ultralow-temperature high-performance that adopts, with and preparation technology's processing step all identical with embodiment 1 with processing parameter.

In the present embodiment, in testing laboratory, the concrete air content of acquisition ultralow-temperature high-performance, ultimate compression strength, perviousness, frost resistance etc. are tested.During actual the test, the mix low-temperature concrete is all identical with embodiment 1 with the method for making the low-temperature concrete test specimen in testing laboratory.

(1) ultralow-temperature high-performance concrete 's air-containing test:

In the present embodiment, the air content testing method that adopts is identical with embodiment 1, and mensuration draws, and the concrete air content of prepared ultralow-temperature high-performance is 3.8% in the present embodiment.

Simultaneously, in testing laboratory, also need the calcium formiate consumption in the used compound antifreezer of preparation ultralow-temperature high-performance concrete is adjusted at 0～1.0wt%, and adopt direct-reading type mixing wastewater with air gas content that the concrete air content of prepared ultralow-temperature high-performance under the different calcium formiate consumptions is tested, test draws: when admixture calcium formiate not, the concrete air content of prepared ultralow-temperature high-performance only has 2.6%, also be lower than the air content 3% of normal concrete mixture, but along with the continuous increase of calcium formiate consumption in the compound antifreezer, the concrete air content of prepared ultralow-temperature high-performance obviously raises.And when the calcium formiate consumption is 0.25wt% in the compound antifreezer, the concrete air content of prepared ultralow-temperature high-performance increases to 3.3%, be higher than normal concrete air content 3%, and the concrete air content of prepared ultralow-temperature high-performance continues along with the increase of calcium formiate consumption in the compound antifreezer to raise, until when the calcium formiate consumption was 0.75wt% in the compound antifreezer, the concrete air content of prepared ultralow-temperature high-performance was 3.6%.

Simultaneously, also need flyash consumption (being the per-cent that flyash weight accounts for the gelling material gross weight) in the used gelling material of preparation ultralow-temperature high-performance concrete is adjusted, and adopt direct-reading type mixing wastewater with air gas content to test, test draws, increase with flyash consumption in the used gelling material, the concrete air content of prepared ultralow-temperature high-performance constantly reduces, this explanation, and flyash has adsorption than intensity to the bubble in the prepared ultralow-temperature high-performance concrete.

Thereby in the actual fabrication process, can prepare the concrete air content requirement of ultralow-temperature high-performance according to need, and in conjunction with calcium formiate consumption in the above-mentioned compound antifreezer affect result and the flyash of prepared ultralow-temperature high-performance concrete (inside contains calcium nitrite) air content is had adsorption than intensity to the bubble in the ultralow-temperature high-performance concrete, calcium formiate consumption in the described compound antifreezer is adjusted accordingly in 0.5%～1.0% scope; Simultaneously, flyash consumption in the described gelling material is adjusted, specifically the weight ratio with cement and flyash in the described gelling material adjusts accordingly in 88～78 ︰, 12～22 scopes.

(2) ultralow-temperature high-performance concrete tensile strength test:

In the present embodiment, the tensile strength testing method that adopts is identical with embodiment 1, the ultimate compression strength of prepared ultralow-temperature high-performance concrete sample was 48MPa when test drew " behind the negative temperature conservation 7d more positive temperature maintenance 28d ", and it is 97% that mark is supported compressive strength rate, and the benchmark compressive strength rate is 100%; The ultimate compression strength of prepared ultralow-temperature high-performance concrete sample is 50MPa when " behind the negative temperature conservation 7d more positive temperature maintenance 56d ", and it is 100% that mark is supported compressive strength rate, and the benchmark compressive strength rate surpasses 102%.

And, also need the calcium formiate consumption in the used compound antifreezer of preparation ultralow-temperature high-performance concrete sample is adjusted at 0～1.0wt%, and employing YES-2000 type digital display hydraulic pressure trier, to made ultralow-temperature high-performance concrete sample at " negative temperature conservation 7d ", " behind the negative temperature conservation 7d more positive temperature maintenance 28d " tests with the ultimate compression strength in the different length of times such as " behind the negative temperature conservation 7d more positive temperature maintenance 56d ", draw after tested: the ultimate compression strength of made ultralow-temperature high-performance concrete sample when " behind the negative temperature conservation 7d more positive temperature maintenance 28d " slightly increases with the increase of calcium formiate consumption in the used compound antifreezer; And from this in length of time section mark support compressive strength rate and benchmark ultimate compression strength recently, gain in strength in this length of time is very fast, mark is supported compressive strength rate and has all been surpassed 85%, and when particularly the calcium formiate consumption was 1wt% in the compound antifreezer, the foster compressive strength rate of its mark and benchmark compressive strength rate were all above 100%.The ultimate compression strength of made ultralow-temperature high-performance concrete sample when " behind the negative temperature conservation 7d more positive temperature maintenance 56d ", not the ultralow-temperature high-performance concrete of admixture calcium formiate, the ultralow-temperature high-performance concrete crushing strength of all the other each calcium formiate consumptions is all about 50MPa in compound antifreezer; And support under the condition at mark, only having calcium formiate consumption in the compound antifreezer is that the ultralow-temperature high-performance concrete crushing strength of 1wt% has surpassed normal concrete.Thereby as a whole,, constantly reduce with calcium formiate consumption in the compound antifreezer before this length of time at " behind the negative temperature conservation 7d more positive temperature maintenance 28d ", the rate of growth of prepared ultralow-temperature high-performance concrete crushing strength is slower; And behind negative temperature conservation 7d positive temperature maintenance 28d to 56d time again, constantly reduce with calcium formiate consumption in the compound antifreezer, the rate of growth of prepared ultralow-temperature high-performance concrete crushing strength is faster.This explanation: calcium formiate can improve the inner concrete early strength development of ultralow-temperature high-performance that is added with nitrous acid, and this raising is accelerated along with the increase of calcium formiate consumption in the compound antifreezer.Relatively comprehensive, when the calcium formiate consumption was 1wt% in the compound antifreezer, the concrete mechanical property of prepared ultralow-temperature high-performance was ideal; When the calcium formiate consumption was 0.25wt% in the compound antifreezer, the concrete mechanical property of prepared ultralow-temperature high-performance was taken second place; When not mixing calcium formiate in the compound antifreezer, the concrete mechanical property of prepared ultralow-temperature high-performance is the poorest.

Simultaneously, also need flyash consumption (being the per-cent that flyash weight accounts for the gelling material gross weight) in the used gelling material of preparation ultralow-temperature high-performance concrete is adjusted, and employing YES-2000 type digital display hydraulic pressure trier, and according to GB/T 50081-2002 " standard for test methods of mechanical properties of ordinary concrete " the concrete tensile strength of made ultralow-temperature high-performance is tested, test draws: when the flyash consumption was 15% in the used gelling material, the concrete ultimate compression strength of prepared ultralow-temperature high-performance was the highest.

Thereby, in the actual fabrication process, can prepare the concrete tensile strength requirement of ultralow-temperature high-performance according to need, and in conjunction with flyash consumption in calcium formiate consumption in the above-mentioned compound antifreezer and the used gelling material on the impact of prepared ultralow-temperature high-performance concrete (inside contains calcium nitrite) tensile strength, calcium formiate consumption in the described compound antifreezer is adjusted accordingly in 0.5%～1.0% scope, and the weight ratio of cement and flyash in the described gelling material is adjusted accordingly in 88～78 ︰, 12～22 scopes.

In addition, by above-mentioned tension test result as can be known, the inside of adopting in the present embodiment is added with that the inner ultralow-temperature high-performance concrete that is added with nitrocalcite has early potent fruit among the ultralow-temperature high-performance concrete of calcium nitrite and the embodiment 1, but the inner concrete early strength function of ultralow-temperature high-performance that is added with calcium nitrite is more remarkable.

(3) ultralow-temperature high-performance concrete permeability test:

In the present embodiment, the permeability test method that adopts is identical with embodiment 1.Draw according to test result, compare with the inner ultralow-temperature high-performance concrete that adds nitrocalcite among the embodiment 1, the ultralow-temperature high-performance concrete that inside adds calcium nitrite generally increases.

In the present embodiment, the concrete displacement flux value of described ultralow-temperature high-performance was 1680C when test drew " behind the negative temperature conservation 7d more positive temperature maintenance 28d ", and the concrete displacement flux value of described ultralow-temperature high-performance is 1230C when " behind the negative temperature conservation 7d more positive temperature maintenance 56d ".

Above-mentioned testing permeability result is arranged as can be known, although it is better than the concrete morning potent usefulness of ultralow-temperature high-performance that inside among the embodiment 1 adds nitrocalcite that inside adds the ultralow-temperature high-performance concrete of calcium nitrite, but calcium nitrite to the alligatoring effect of negative temperature concrete pore structure also clearly, can play certain improvement effect with the adding of calcium formiate, but concrete perviousness is still undesirable after its sclerosis.

Simultaneously, also need flyash consumption (being the per-cent that flyash weight accounts for the gelling material gross weight) in the used gelling material of preparation ultralow-temperature high-performance concrete is adjusted, and adopt NEL-PEU type concrete charge pass determinator that the tensile strength of made ultralow-temperature high-performance concrete sample is tested, test draws: with the increase of flyash consumption in the used gelling material, the perviousness of prepared ultralow-temperature high-performance concrete when " behind the negative temperature conservation 7d more positive temperature maintenance 28d " all increases gradually.Viewpoint according to Berry Malhotra, can reduce bonding between aggregate and the grout at the aquation initial stage as the flyash of gelling material, the moisture film of fly ash grain surface adsorption will make the zone of transition more porous that becomes, therefore under the negative temperature conservation condition, flyash in the used gelling material has negative effect to concrete perviousness, and this effect is serious all the more along with the increase of flyash consumption.Therefore, for the higher negative temperature concrete structure of life requirement, mixing of flyash should be prudent, mixes less or fly ash not, to guarantee the life-span of engineering as far as possible.In addition, owing to adopt the inner concrete perviousness of ultralow-temperature high-performance that adds calcium nitrite in the present embodiment, the concrete perviousness of ultralow-temperature high-performance that adds nitrocalcite than inside among the embodiment 1 is much bigger, thereby the inner ultralow-temperature high-performance concrete that adds calcium nitrite is subjected to the impact of flyash side effect also even more serious.

Thereby, in the actual fabrication process, can prepare the concrete perviousness requirement of ultralow-temperature high-performance according to need, and in conjunction with flyash consumption in calcium formiate consumption in the above-mentioned compound antifreezer and the used gelling material on the infiltrative impact of prepared ultralow-temperature high-performance concrete (inside contains calcium nitrite), calcium formiate consumption in the described compound antifreezer is adjusted accordingly in 0.5%～1.0% scope, and the weight ratio of cement and flyash in the described gelling material is adjusted accordingly in 88～78 ︰, 12～22 scopes.

(4) ultralow-temperature high-performance concrete antifreezing property testing:

In the present embodiment, the frost resistance testing method that adopts is identical with embodiment 1, draws after tested: behind 225 freeze-thaw cycle, the mass loss rate of ultralow-temperature high-performance concrete sample is 2.5%, and relative dynamic elastic modulus drops to 40%; And test specimen can stand 175 times～200 times freeze-thaw cycle destruction.

And, also need the calcium formiate consumption in the used compound antifreezer of preparation ultralow-temperature high-performance concrete sample is adjusted at 0～1.0wt%, and adopt above-mentioned antifreezing test method that the frost resistance of prepared ultralow-temperature high-performance concrete sample is tested, test result is as follows: compare with the inner ultralow-temperature high-performance concrete that is added with nitrocalcite among the embodiment 1, the ultralow-temperature high-performance concrete that the inside of adopting in the present embodiment is added with calcium nitrite is done the time spent standing freeze-thaw cycle, not only freezing tolerance is poor, and inner collapse mode also is not quite similar, especially drop to below 80% at the concrete dynamic modulus of elasticity, when standing freeze-thaw damage again, its relative dynamic elastic modulus acutely descends, and internal structure is burst apart.During the admixture calcium formiate, inside is not added with the concrete frost resistance extreme difference of ultralow-temperature high-performance of calcium nitrite, and its relative dynamic elastic modulus just drops to 56% behind 75 freeze-thaw cycle, and mass loss reaches 2.8%.After mixing calcium formiate, the concrete frost resistance of ultralow-temperature high-performance that inside is added with calcium nitrite increases, the amount of peeling off on surface obviously reduces, and the calcium formiate consumption is when being 0.75wt%, it is best that inside is added with the ultralow-temperature high-performance concrete antifreezing performance of calcium nitrite, and the freeze-thaw cycle that can stand 175 times～200 times destroys.

Simultaneously, also need flyash consumption (being the per-cent that flyash weight accounts for the gelling material gross weight) in the used gelling material of preparation ultralow-temperature high-performance concrete is adjusted, and tackle mutually the concrete frost resistance of prepared ultralow-temperature high-performance and test, test draws: with the increase of flyash consumption in the gelling material, the concrete frost resistance of prepared ultralow-temperature high-performance obviously reduces.Wherein, the flyash consumption is 10% in the gelling material, and it is best that inside is added with the concrete frost resistance of ultralow-temperature high-performance of calcium nitrite.But, to compare with the inner ultralow-temperature high-performance concrete that is added with nitrocalcite among the embodiment 1, it is relatively poor to adopt inside to be added with the concrete frost resistance of ultralow-temperature high-performance of calcium nitrite in the present embodiment.When the flyash consumption was 10% in the gelling material, the freezing-thawing cycles that can stand also only had 200 times～225 times, and its mass loss is little; In addition, when the flyash consumption was 20%～25%, its frost resistance changed little, and its freeze-thaw cycle destroys number of times between 100～125 times, and mass loss is maximum.

Thereby, in the actual fabrication process, can prepare the concrete frost resistance requirement of ultralow-temperature high-performance according to need, and in conjunction with flyash consumption in calcium formiate consumption in the above-mentioned compound antifreezer and the used gelling material on the impact of prepared ultralow-temperature high-performance concrete (inside contains calcium nitrite) frost resistance, calcium formiate consumption in the described compound antifreezer is adjusted accordingly in 0.5%～1.0% scope, and the weight ratio of cement and flyash in the described gelling material is adjusted accordingly in 88～78 ︰, 12～22 scopes.

In sum, be added with the ultralow-temperature high-performance concrete of calcium nitrite for inside, the concrete air content of ultralow-temperature high-performance increases with the increase of calcium formiate consumption, and when the calcium formiate consumption was 0.75wt%, air content reached maximum; Before this length of time, the calcium formiate consumption is less at " behind the negative temperature conservation 7d more positive temperature maintenance 28d ", and the concrete ultimate compression strength rate of growth of ultralow-temperature high-performance is slower, and behind the negative temperature conservation 7d again during the positive temperature maintenance 28d to 56d, then just opposite; And the adding of calcium formiate has improved the development of early age strength of concrete, and this raising is accelerated along with the increase of its volume; With the increase of calcium formiate consumption, raise again after the concrete perviousness of ultralow-temperature high-performance reduces first, and it is relatively better to adopt inside to be added with the concrete perviousness of ultralow-temperature high-performance of nitrocalcite among the embodiment 1; In standing the freeze-thaw cycle destructive process, it is even more serious that inner spalling damages outside spalling damage.

Be added with the ultralow-temperature high-performance concrete of calcium nitrite for inside, increase along with flyash consumption in the gelling material, the concrete air content of ultralow-temperature high-performance obviously reduces, and adopts the reduction amplitude of the inner ultralow-temperature high-performance concrete 's air-containing that is added with calcium nitrite relatively large in the present embodiment; The flyash consumption is 20% when following in the gelling material, and the concrete early strength function of ultralow-temperature high-performance is more remarkable; Under the negative temperature conservation condition, flyash has disadvantageous effect to the concrete perviousness of ultralow-temperature high-performance, and influence degree increases along with the increase of flyash consumption.Compound antifreezer of the present invention has not only been avoided the detrimental action of part inorganic salt to concrete frost resistance, and by adjusting its inner each amounts of components, also can increase to the concrete frost resistance of ultralow-temperature high-performance.

The above; it only is preferred embodiment of the present invention; be not that the present invention is imposed any restrictions, every any simple modification, change and equivalent structure of above embodiment being done according to the technology of the present invention essence changes, and all still belongs in the protection domain of technical solution of the present invention.

Claims (10)

1. severe cold area construction of railways ultralow-temperature high-performance concrete, it is characterized in that: carry out even mix by gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water and form, the concrete unit weight of this ultralow-temperature high-performance is 2350kg/m ³～2450kg/m ³, and the concrete maximum water-cement ratio of described ultralow-temperature high-performance and sand coarse aggregate ratio, design with the mix proportion method of design all according to the design paper requirement that needs the construction concrete structure, and according to construction of railways; It is the high performance concrete of constructing under 0 ℃～-40 ℃ conditions that described ultralow-temperature high-performance concrete refers to be applicable to envrionment temperature;

Described gelling material is that the ratio of 15～20 ︰ 85～80 evenly mixes by cement and mineral admixture according to weight ratio;

The water-reducing rate of described high efficiency water reducing agent is not less than 25%, and the weight ratio of described high efficiency water reducing agent and described gelling material is 0.5 ︰, 100～1 ︰ 100;

The weight ratio of described compound antifreezer and described gelling material is 3 ︰, 100～6 ︰ 100; The composition of described compound antifreezer is by weight: nitrate 30%～35%, and organic compound 30%～33%, calcium formiate 0.5%～1%, surplus is water; Described nitrate is nitrocalcite or calcium nitrite, and described organic compound is methyl alcohol or ethanol.

2. according to severe cold area construction of railways ultralow-temperature high-performance concrete claimed in claim 1, it is characterized in that: the concrete minimum gel material content of described ultralow-temperature high-performance and maximum unit water consumption, design with the mix proportion method of design all according to the design paper requirement that needs the construction concrete structure, and according to construction of railways.

3. according to claim 1 or 2 described severe cold area construction of railways ultralow-temperature high-performance concrete, it is characterized in that: the concrete maximum water-cement ratio of described ultralow-temperature high-performance be 0.4 and its sand coarse aggregate ratio be 32%～44%.

4. according to severe cold area construction of railways ultralow-temperature high-performance concrete claimed in claim 2, it is characterized in that: the concrete minimum gel material content of described ultralow-temperature high-performance is 360kg/m ³, the maximum unit water consumption is 165kg/m ³

5. according to severe cold area construction of railways ultralow-temperature high-performance concrete claimed in claim 3, it is characterized in that: the concrete water-cement ratio of described ultralow-temperature high-performance is 0.26～0.4; In the described ultralow-temperature high-performance concrete, the weight ratio of sand and gelling material is 1.40～1.80.

6. one kind prepares the as claimed in claim 1 concrete technique of ultralow-temperature high-performance, it is characterized in that this technique may further comprise the steps:

Step 1, compound antifreezer preparation, its preparation process is as follows:

Step 101, nitrate and calcium formiate preheating: with described nitrate and calcium formiate, be heated to respectively 40 ℃～70 ℃;

Step 102, evenly be mixed: with described nitrate and the calcium formiate after the preheating in water and the step 101, after mixing according to the design proportioning, make described compound antifreezer;

Step 2, even mix: after gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water carried out even mix according to the design proportioning, acquisition unit weight was 2350kg/m ³～2450kg/m ³The ultralow-temperature high-performance concrete.

7. according to technique claimed in claim 6, it is characterized in that: when in the step 102 the described nitrate after the preheating in water and the step 101 and calcium formiate being mixed, adopt the circulation compound reactor to mix; Described circulation compound reactor comprises normal-pressure reaction kettle and the liquid circulation line that is installed on the described normal-pressure reaction kettle, on the described liquid circulation line recycle pump is housed, and described circulation compound reactor mixes evenly in the mode that described recycle pump pumps into circulating liquid in the described normal-pressure reaction kettle.

8. according to claim 6 or 7 described techniques, it is characterized in that: in the step 2 gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water are carried out adopting first heating installation that the water of the described ultralow-temperature high-performance the reinforcement of concrete of mix is heated to 50 ℃～70 ℃ before the even mix; Afterwards, again with sand, rubble, water, mineral admixture, cement and concrete admixture, enter even mix in the whipping device according to the design proportioning by first extremely rear respectively input, just obtain the described ultralow-temperature high-performance concrete that mix forms;

Wherein said concrete admixture comprises high efficiency water reducing agent and compound antifreezer.

9. according to technique claimed in claim 8, it is characterized in that: when in the step 2 gelling material, sand, rubble, high efficiency water reducing agent, compound antifreezer and water being carried out even mix, the rotating speed of described whipping device is 23.5r/min ± 3r/min, and duration of mixing is no less than 120s.

10. according to technique claimed in claim 8, it is characterized in that: when in the step 2 sand, rubble, water, mineral admixture, cement and concrete admixture being thrown in, the temperature of described sand, rubble, mineral admixture and cement all is not less than 0 ℃, and described high efficiency water reducing agent and compound antifreezer in the described concrete admixture are liquid state.

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