CN108675711A - Ready-mixed concrete construction method under high and cold alternate freezing and thawing environment - Google Patents
Ready-mixed concrete construction method under high and cold alternate freezing and thawing environment Download PDFInfo
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- CN108675711A CN108675711A CN201810449984.XA CN201810449984A CN108675711A CN 108675711 A CN108675711 A CN 108675711A CN 201810449984 A CN201810449984 A CN 201810449984A CN 108675711 A CN108675711 A CN 108675711A
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
- B28C5/003—Methods for mixing
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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- On-Site Construction Work That Accompanies The Preparation And Application Of Concrete (AREA)
Abstract
A kind of ready-mixed concrete construction method under high and cold alternate freezing and thawing environment, steps are as follows：（1）, feed intake according to following weight parts：Rubble 1015~1100, sand 730~770, cement 330~365, flyash 82~92, water-reducing agent 4.1~4.6 and water 123~152；（2）, material entered into mixing and blending machine, 1~2 minute is mixed under 600~900 revs/min of mixing speed to uniform；Flow then is poured according to the prior art, concrete slurry pump is delivered to and pours target, pour, vibrate, keep the temperature, form removal and covering.The present invention does not use antifreezing agent, reduces concrete reinforcement and generates corrosion；By reducing the ratio of mud, the water-cement ratio of concrete is controlled, mixing water amount is reduced, reduces inside concrete gap, reduces concrete moisture content, the method for improving early strength achievees the purpose that the anti-freeze-thaw damage of concrete.Engineering cost is saved, it is ensured that construction safety, project progress and quality.
Description
Technical field
The invention belongs to ready-mixed concrete technical field of construction, are specifically to provide under a kind of high and cold alternate freezing and thawing environment
Ready-mixed concrete construction method, be suitable for highland and severe cold and ready-mixed concrete under multigelation alternate environment round the clock constructed.
Background technology
Qinghai-xizang Plateau Region mean sea level 4000m, due to atmospheric transparency height, year solar irradiation value be up to 5850~
7950MJ/m2, dust storm is big, and air humidity is low, and ultraviolet light is strong, usually occurs the positive and negative alternating of diurnal temperature so as to cause this area
Deng extreme meteorology, to the construction project in this area, especially concrete construction brings prodigious difficulty.
The towns Yushu district, Qinghai Zhou Jiegu are located in East of Tibetan Plateau, are located at Tibetan Autonomous Prefecture of Yushu most east, domestic average sea
4493.4 meters are pulled out, landform is based on the plateau of mountainous region；Belong to typical highland and severe cold weather, annual point without the four seasons, year minimum gas
- 29.2 DEG C of temperature, 28 DEG C of the highest temperature, in terms of the meteorological data being collected into, the project location towns Yushu Jie Gu are in addition to annual 7,8
There are occasional exceptions within two months, will appear night icing phenomenon remaining month, and day and night temperature is usually between -5 DEG C~+5 DEG C, throughout the year
With the complexity such as heavy snow, early frost, arid, hail, atrocious weather, annual mean ground temperature is big.
Engineering construction at present is generally all during annual May~August, expenditure of construction long so as to cause the engineering construction period
It is high, form serious restrict to the large-scale construction in this area and development.Alternatively, time limit duration is required, it must
The construction project that must be constructed during April~September is generally prevented using antifreezing agent and air entraining agent are added in concrete
Concrete through freeze-thaw test.So, it due to the chemical action of antifreezing agent, is on the one hand affected with concrete durability, separately
On the one hand with the reinforcing bar of concrete combined effect by the chemical attack of antifreezing agent, corrosion is generated, concrete and engineering structure
Service life is had a greatly reduced quality, and economic loss is brought to countries and regions.
Invention content
The technical problem to be solved in the present invention is to provide a kind of raising concrete mix workability, homogenieity and work
Property, promote the ready-mixed concrete construction method under the high and cold alternate freezing and thawing environment of the quality of concrete product.This method is suitable
Close the construction of durability concrete under the positive and negative temperature alternate environment in highlands, it is ensured that construction quality.
The present invention solves above-mentioned technical problem and is adopted the technical scheme that：A kind of premixing under high and cold alternate freezing and thawing environment
Concrete construction method, steps are as follows：
（1）, feed intake according to following weight parts：Rubble 1015~1100, sand 730~770, cement 330~365, flyash 82~
92, water-reducing agent 4.1~4.6 and water 123~152；
（2）, by step（1）Material enters mixing and blending machine, and 1~2 minute is stirred under 600~900 revs/min of mixing speed extremely
Uniformly；Flow then is poured according to the prior art, concrete slurry pump is delivered to and pours target, pours, vibrates, keeping the temperature, tearing open
Mould and covering.
Before mixing, combining environmental temperature needs to take antifreeze method, specially：
（1）, for concrete mixer and engineering structure set up roof insulating, kept the temperature, ensure that temperature of shed is not less than 0.0
℃.When temperature is less than -15 DEG C in continuous three days, should stop constructing.
（2）, ice and snow must not be contained in rubble and sand, that is, coarse-fine aggregate, freeze block；It is many if there is that should be carried out to aggregate dicang
It was heated in 72 hours.
（3）, concrete raw material it must be heated before mixing and stirring, preferentially water is heated；When temperature is relatively low and adds
When hot water cannot be satisfied temperature requirement, Heat preservation should be carried out to aggregate bin.
When construction, it is ensured that, should be by such as if being less than 13 DEG C if the out-of-machine temperature of concrete is not less than 13~15 DEG C
Lower measure is kept the temperature and is preheated to raw material：
（1）Cement, flyash and powdered additive should not directly heat, but take effective Insulation, ensure in positive warm condition
Lower use；
（2）Mixing water should be heated using boiler, and heating temperature is preferably controlled at 30~70 DEG C；
（3）Sand, stone material should be preheated using dicang, and heating temperature is preferably controlled at 5~20 DEG C；
Concrete out-of-machine temperature is not lower than 13~15 DEG C；The out-of-machine temperature T of concretecIt can be pressed with the temperature relation of raw material
Formula is calculated：
Tc= ΣTiWc/ΣWc
In formula：TcThe out-of-machine temperature of concrete mix（℃）；TiThe respective temperature of concrete raw material（℃）；
WiThe folk prescription dosage of concrete raw material（kg）；WcThe heat equivalent of concrete raw material（kJ/℃）, concrete when calculating
The specific heat c of raw material（KJ/kgK), cement, sand, stone, admixture take 0.84, and water and liquid water-reducing agent take 4.2.
It is caused by three main causes that concrete, which generates freeze-thaw damage,：(1) there is many holes in concrete；
(2) under certain circumstances, these holes are filled with water；(3) under cold conditions, the constantly freeze thawing of the water in hole variation pair
Hole wall generates continually changing interior pressure, just will produce freeze-thaw damage (water knot when interior pressure is more than the tensile strength of concrete
Its volume expansion about 9% or so after ice), above three conditions lack one, and freeze-thaw damage will not all occur for concrete.
The present invention is directed to the reality that existing concrete freezing proof technique influences concrete durability, by reducing coagulation
Native internal voids, reduce concrete moisture content, and the method for improving early strength achievees the purpose that the anti-freeze-thaw damage of concrete.This
Engineering cost has been saved in invention, it is ensured that construction safety, project progress and quality.
The design principle of mixture ratio for durable concrete is intensity required by meeting engineering design and construction and easily
Property, under the conditions of crack resistance, frost resistance, impermeability and unit weight etc., it is ensured that concrete has enough freeze proof critical strong in a short time
Degree, ensures the durability of concrete.The reason of present invention mainly generates freeze-thaw damage from concrete is started with, and reasonable design goes out mixed
The solidifying various composition material dosages of soil, prevent concrete through freeze-thaw test.First, using concrete high efficiency water reducing agent, concrete is reduced
Water consumption；Second, the water-cement ratio of control concrete, is further reduced mixing water amount；Third, filling coagulation using flyash
Some perforations in soil, while utilizing the SiO being rich in flyash2Secondary response formed in netted cement fill concrete
Some perforations, also improve concrete intensity, frost resistance and durability.
The size of water-cement ratio is to influence the principal element of concrete density, to ensure the early strength of concrete and durable
Property, it is necessary to strictly control the ratio of mud.Unit consumption of water is to influence concrete antifreezing performance, control concrete batching system mobility
Principal element.By using high efficiency water reducing agent, meet the requirement of the mobility of concrete batching system, reduce water consumption, it is ensured that is mixed
Coagulate the anti-freezing property of soil.
Active fly ash is added in raw material of the present invention, main active is silica, passes through its secondary counter
The porosity that concrete should be reduced, to improve the compactness of concrete；Concrete is reduced by the way that high efficiency water reducing agent is added
Water consumption improves concrete durability method；The early strength for improving concrete, solves concrete under positive and negative alternation condition
Freeze-thaw damage extends the service life of engineering structure.Their mechanism of action is：
Cement in concrete produces the Ca of a large amount of water-soluble weakness in hydration process（OH）2It is mixed in coagulation
In soil, they are in net distribution, form hole and infiltration lane, this be concrete frost resistance, intensity, impervious, durability and its
The main reason for his performance is restricted.
Flyash is volcano ash effect and particles filled effect to the Influencing Mechanism of concrete：On the one hand, in flyash
Amorphous Si O2The Ca generated with hydrated cementitious（OH）2Chemical combination makes Behavior of Hardened Cement Paste component C-S-H hyrates acutely increase.Meanwhile
Because of SiO2Particle absorbs hydrolysis product of cement Ca quickly（OH）2And secondary response occurs therewith, make the Ca around cement granules2+From
Sub- saturated concentration state changes, and continuation aquation is exposed in the fresh surface of cement granules again, accelerates hydrated cementitious
Process forms a large amount of fine and close C-S-H hyrate reticular structures, they are loaded with the cavity in concrete, improve coagulation
Native intensity；On the other hand, since fly ash grain is superfine, a large amount of fly ash grain and its hydrated product play filling effect, change
The microstructure of Behavior of Hardened Cement Paste has been apt to it, so as to improve the frost resistance and durability of concrete.
In normal concrete, since mixing water amount is more much bigger than the water needed for hydrated cementitious, under normal circumstances, water
Water consumption needed for muddy water is about 20% of cement weight or so, and mixing water amount when constructing is 50% or so, even more
It is more.Extra water forms various a large amount of apertures in concrete and Behavior of Hardened Cement Paste and the interface zone to gather materials after the concrete has set
Gap, and micro-pipe and fine fisssure caused by mixture bleeding and concrete dehydration shrinkage, these defects are to lead to agent on crack resistance of concrete
Jelly property, the basic reason of intensity, impervious, durability and other poor performances.The present invention reduces and eliminates as far as possible these defects,
Improve the structure of concrete, basic measure is to add high efficiency water reducing agent, reduces the water-cement ratio of concrete.
The size of sand coarse aggregate ratio, can also reduce the mobility of mix, and seriously affect the cohesiveness of concrete batching system, water conservation
Property and pumpability.Therefore Rational Sand Rate, i.e. optical sand percentage are taken by experiment.
Specific implementation mode
Following three embodiments are case history, and project name is Yushu museum engineering, the total floor space of engineering
1.6 ten thousand m2, building overall length 180m, wide 60m, construction area 11500.3m2.
During construction Yushu museum, since project is located in High aititude extremely frigid zones, natural conditions are disliked
Bad, temperature is low, and day and night temperature is big, throughout the year with the complicated climatic condition such as heavy snow, early frost, arid, hail, dead season concrete construction
Amount is big, and it is bent to bring great challenge, especially engineering moulding to the durability of concrete component construction and concrete itself
Face structure more increases difficulty, easy tos produce freeze-thaw damage because its concrete structure is thin.The technical issues of for occurring, we
The tackling key problem of plateau high altitude localities concrete construction key is carried out, it is proposed that without antifreezing agent coagulation under positive negative temperature alternate environment
Native construction method, solves the long-standing problem key technology difficulty of highlands concrete construction, and satisfactory completes Qinghai jade
Set the landmark building of this Qinghai-Tibet Platean of autonomous prefecture's this large public building with national characters of museum.
Following embodiments by frigid plateau region pump C30, C35 and C40 concrete, fully meet concrete structure
The strength grade of design requirement, meets the required concrete batching system workability of construction, and the durability for meeting concrete is (freeze proof
Grade, seepage-resistant grade etc.).Under the premise of meeting every technical performance, make each composition material economical rationality, with ensure that cajaput
Quality and the duration for shaking post-disaster reconstruction project, by the height favorable comment in Qinghai Province, cajaput state government and user, the project obtains at present
Obtain the prize of Qinghai Province's architectural engineering " rivers source " cup.
Embodiment 1, C40 concrete；It feeds intake according to following weight parts：10170 kilograms of rubble, 7690 kilograms of sand, cement
1450 kilograms of 3640 kilograms, 910 kilograms of flyash, 46 kilograms of water-reducing agent and water；The above-mentioned material of step is entered into mixing and blending machine,
1 minute is stirred under 900 revs/min of mixing speed to uniform；Flow then is poured according to the prior art, concrete slurry is pumped
It is delivered to and pours target, pour, vibrate, keeping the temperature, form removal and covering.
One, raw material technology require be respectively：
1, under the conditions of the multigelation of cement severe cold area open work concrete, cold district is in fluctuation in stage range
Interior concrete should preferentially select portland cement, ordinary cement to ensure that concrete has sufficient early strength.According to
Supply condition and other factors, the PO.42.5 cement of cement selection Qilian mountains Cement Co., Ltd production, by GB175 detections
Cement physical properties are shown in Table 1.
2, flyash flyash is dispatched from the factory using Lanzhou Xi Gu steam power plants, and specification type is II grade of F classes.Fineness 19%, needs water
Ratio 99% is measured, main chemical compositions are shown in Table 2.
3, thick, fine aggregate aggregate plays skeleton function in concrete, and thick, fine aggregate is that concrete is main composition material,
Stone heap in concrete is polymerized to close framework, and fine aggregate and cement are mixed into mortar, fill the gap of framework.Sand it is thick
The quality of thin degree and grain composition, has a significant impact to the technical performance of concrete.When the dosage of sand it is identical if it is excessively thick, if
The concrete cohesiveness mixed out is poor, easy tos produce isolation, excreting water phenomenon；If meticulous, its total surface area is larger, needs
The cement mortar for being enclosed in sand surface is more, so the sand used in the concrete of mixing both should not be excessively thick or should not be meticulous.
Prepare sand or medium coarse sand in the appropriate to the occasion preferential selection of pump concrete.
The clay content (i.e. grain size is less than the dust of 0.080mm, the total content of mud and clay) of sand, there is concrete quality
The spare of very big influence, these superfine particles forms wrapping layer in aggregate surface, interferes the bonding of aggregate and cement；Or with loose
Particle occur, substantially increase surface area, thus increase water requirement；Especially clay particle, volume is unstable, dry
When shrink, expanded when moist, have prodigious destruction to concrete.In short, clay content is excessive, concrete easy tos produce plasticity
Desciccation crack reduces concrete temperature, increases laitance amount, reduces the wearability of concrete.For there is freeze proof other particular/special requirements
Sand for Concrete, clay content should not exceed 3.0%.
Clod content refers to that grain size is more than 1.25mm in sand, handles the content that 0.630mm particles are become less than after pinching, right
Concrete quality has the mud of larger impact and the total content of clay, to there is the concrete of freeze proof, impervious or other particular/special requirements,
The clay content of rubble or cobble used should not exceed 1.0%.
When being substantially the mountain flour of non-stick soil property such as clay content, clay content also must not exceed 3.0%.
Slightly, fine aggregate is by the production and supply of cajaput sandstone factory of the second engineering company of group of China Railway 21 Bureau.Test result
For：As fine aggregate sand be II classes in sand, fineness modulus 2.8, clay content 2.7%, bulk density 1544, apparent density 2691,
Porosity 42.6%；
As the rubble of coarse aggregate, 9.5~31.5mm of grade, clay content 0.2%, bulk density 1544, apparent density 2677, hole
Gap rate 42.4%.
4, water-reducing agent reduces the water content in concrete as possible under the premise of the abundant aquation of cement in ensureing concrete,
Under normal circumstances, the water requirement of the abundant aquation of cement is about the 20% of cement weight, in order to reduce liquid phase extra in concrete,
It avoids, by freeze-thaw damage, needing to participate in cement water reducing agent.According to experiment, the high efficiency water reducing agent that project is selected is that Shanxi Huang is risen
The HT-HPC poly carboxylic acid series water reducers of Chemical Co., Ltd.'s production.
5, mixing water：Mixing water uses life well water.
Two, construction method field management
The raw material that reply is selected before construction are tested, and comply with standard and process require that rear can be used.
Before construction, copes with thick, fine aggregate moisture content and test, and on the basis of theoretical match ratio, to mixing and stirring use
Water is reduced.Analysis must be collected to the weather meteorological data of project location, imminent temperature change is wanted
There are counter-measure and prediction scheme.
When temperature is less than -10 DEG C, warming heating measures are taken coarse-fine aggregate dicang, are stirred for the concrete of construction
Machine and engineering structure set up roof insulating, are kept the temperature, and ensure that temperature of shed is not less than 0.0 DEG C.When continuous three days of temperature less than-
At 15 DEG C, it should stop constructing.
Pay attention to that ice and snow must not be contained in aggregate when construction, freeze block；If there is that should be carried out to aggregate dicang no less than 72 hours
Heating.
The raw material of concrete must heat it before mixing and stirring, and preferentially be heated to water.When temperature is relatively low and heating water
When cannot be satisfied temperature requirement, Heat preservation should be carried out to aggregate bin.
When construction, if the out-of-machine temperature of concrete is less than 13~15 DEG C DEG C, raw material should be carried out by following measure
Heat preservation and preheating：
1, cement, flyash and powdered additive should not directly heat, but take effective Insulation, ensure under the conditions of positive temperature
It uses；
2, mixing water should be heated using boiler, and heating temperature is preferably controlled at 30~70 DEG C；
3, sand, stone material should be preheated using dicang, and heating temperature is preferably controlled at 5~20 DEG C；
4, the out-of-machine temperature T of concretecIt can be calculated as the following formula with the temperature relation of raw material：
Tc= ΣTiWc/ΣWc
In formula：TcThe out-of-machine temperature of concrete mix（℃）；TiThe respective temperature of concrete raw material（℃）；
WiThe folk prescription dosage of concrete raw material（kg）；WcThe heat equivalent of concrete raw material（kJ/℃）, concrete when calculating
The specific heat c of raw material（KJ/kgK), cement, sand, stone, admixture take 0.84, and water and liquid water-reducing agent take 4.2.
In order to ensure that out-of-machine temperature, the slump and the pumpability of concrete, concrete answer concentrated compactness.Concrete is mixing and stirring
Before, raw material should be preheated, with hot water injection's blender, the mixing time should properly increase 15~30s, control coagulation
Native out-of-machine temperature makes it be not lower than 13~15 DEG C.The agitator tank of the haulage vehicle of concrete is kept the temperature, blender and transport
Vehicle is clean with hot water injection after completing whole tasks.
Before pouring, it should ensure that the molding temperature of the concrete of winter construction is not less than 10 ± 2 DEG C.In extremely frigid zones, in order to
Ensure that the tensile strength and compactness of concrete, concreting generally use secondary vibration technique, meanwhile, to use secondary smear
The contraction fissure of concrete surface is reduced in face.
When extremely frigid zones are constructed, to prevent the forfeiture quickly of concrete internal temperature, exposed surface from should cover guarantor in time
Warm layer.When constructing under the conditions of positive temperature, moisture-keeping maintaining should be carried out to the concrete poured, prevent concrete dehydration from cracking.Meanwhile
Should take measures freeze injury caused by preventing precipitate cooling.
To ensure the construction quality of construction period concrete and rationally accelerating construction progress, it is necessary to pre- in concreting
Same condition test specimen and standard specimen are stayed, to understand concrete strength growth pattern, the foundation as maintenance and form removal.
Behind concreting receipts face, plastic foil and insulating layer should be used to cover immediately, and set up roof insulating.When temperature of shed is low
When 0 DEG C, heating measures are taken.
According to the compression strength of same condition concrete sample, determine the striking time of concrete by related standard, template and
Insulating layer reaches the dismountable striking time in requirement rear in concrete preferably to carry out in environment temperature higher daytime.It is mixed after form removal
Solidifying soil must be covered with slow burning straw curtain in time, and keep fire-retardant grass dry, make its Slow cooling.Forbid water seasoning, after form removal
The box out of column angle should be protected immediately, especially balcony fence, at corner, the positions such as stair step.
Embodiment 2, C35 concrete；It feeds intake according to following weight parts：10930 kilograms of rubble, 7500 kilograms of sand, cement
1230 kilograms of 3440 kilograms, 860 kilograms of flyash, 43 kilograms of water-reducing agent and water；The above-mentioned material of step is entered into mixing and blending machine,
2 minutes are stirred under 600 revs/min of mixing speed to uniform；Flow then is poured according to the prior art, concrete slurry is defeated
It send to pouring target, pour, vibrate, keep the temperature, form removal and covering.The technology of raw material requires and construction method field management, together
Embodiment 1.
Embodiment 3, C30 concrete；It feeds intake according to following weight parts：10960 kilograms of rubble, 7430 kilograms of sand, cement
1520 kilograms of 3280 kilograms, 820 kilograms of flyash, 41 kilograms of water-reducing agent and water；The above-mentioned material of step is entered into mixing and blending machine,
1.5 minutes are stirred under 600 revs/min of mixing speed to uniform；Flow then is poured according to the prior art, by concrete slurry
It is delivered to and pours target, pour, vibrate, keeping the temperature, form removal and covering.The technology of raw material requires and construction method field management,
With embodiment 1.
The engineering construction match ratio table 3 of above-described embodiment C30, C35 and C40 concrete.
When C30 concrete constructions, sand is measured, the moisture content of rubble is respectively 1.8%, 0.0%；
When C35 concrete constructions, sand is measured, the moisture content of rubble is respectively 4.0%, 1.0%；
When C40 concrete constructions, sand is measured, the moisture content of rubble is respectively 2.5%, 0.0%.
Above-described embodiment C30, C35 and C40 concrete works have carried out following content in Yushu museum building-site
Experiment and verification：
One, concrete mixing performance
The unit weight of C30, C35 and C40 concrete mix of this experiment is respectively 2405,2400 and 2390Kgm-3；Gassiness
Amount is 2.8%；C30, C35 and C40 concrete mix slump are respectively 170,170 and 170 mm, and divergence is respectively
600,650 and 660 mm, slump consistancy test is according to GB/T 50080-2006《Standard for test methods of properties of ordinary concrete mixture mark
It is accurate》It carries out, is respectively 170,170 and 160 mm after the mixing 2h measured, without apparent slump-loss in 2 hours.
Two, mechanical performance of concrete is tested
This test method is according to GB/T 50081-2002《Standard for test methods of mechanical properties of ordinary concrete》It carries out.
The peripheral test result of C30, C35 and C40 concrete is as follows：Compressive strength test sample dimensions 150 × 150 ×
150 mm, test result are shown in Table 4.
Three, concrete durability
Test method is according to GB/T50082-2009《Normal concrete chronicity and durability test method standard》It carries out.
C30, C35 and C40 concrete frost resistance：100 Frozen-thawed cycleds, this batch of coagulation are carried out after 28 days in standard curing
For soil through 100 freezing and thawing tests, the loss of strength rate of inspected C30, C35 and C40 concrete is 3.4,3.1 and 2.9%,
Elasticity modulus loss is 0%, and appearance is unchanged, is shown excellent by inspection concrete antifreezing performance.
Anti-carbonation properties：C30, C35 and C40 concrete sample carry out carbonization test after 28 ages, will after being carbonized 28 days
Test specimen breaks type, sprays phenolphthalein alcoholic solution in the fresh face of broken type, breaks type face without apparent carbonization, only surface layer has bleaches on a small quantity.
Anti-permeability performance：C30, C35 and C40 carry out impermeability test after supporting 28 days, test since hydraulic pressure is 0.1MPa, pressurization
To the maximum pressurization value 4.0Mpa of Anti-leakage instrument, situation is permeated in observation test specimen end face without appearance.
Claims (3)
1. the ready-mixed concrete construction method under a kind of high and cold alternate freezing and thawing environment, it is characterised in that steps are as follows：
（1）, feed intake according to following weight parts：Rubble 1015~1100, sand 730~770, cement 330~365, flyash 82~
92, water-reducing agent 4.1~4.6 and water 123~152；
（2）, by step（1）Material enters mixing and blending machine, and 1~2 point is mixed under 600~900 revs/min of mixing speed
Clock is to uniform；Flow then is poured according to the prior art, concrete slurry pump is delivered to and pours target, pours, vibrates, protecting
Temperature, form removal and covering.
2. the ready-mixed concrete construction method under a kind of high and cold alternate freezing and thawing environment as described in claim 1, it is characterised in that
Before mixing, combining environmental temperature needs to take antifreeze method, specially：
（1）, concrete mixer for construction and engineering structure set up roof insulating, kept the temperature, ensure that temperature of shed is not low
In 0.0 DEG C；
When temperature is less than -15 DEG C in continuous three days, should stop constructing；
（2）, ice and snow must not be contained in rubble and sand, that is, coarse-fine aggregate, freeze block；If there is no less than 72 should be carried out to aggregate dicang
Hour heating；
（3）, concrete raw material it must be heated before mixing and stirring, preferentially water is heated；When temperature is relatively low and heating water
When cannot be satisfied temperature requirement, Heat preservation should be carried out to aggregate bin.
3. the ready-mixed concrete construction method under a kind of high and cold alternate freezing and thawing environment as claimed in claim 2, it is characterised in that：
When construction, it is ensured that, should be by following measure to former material if be less than if the out-of-machine temperature of concrete is not less than 13~15 DEG C
Material is kept the temperature and is preheated：
（1）Cement, flyash and powdered additive should not directly heat, but take effective Insulation, ensure in positive warm condition
Lower use；
（2）Mixing water should be heated using boiler, and heating temperature is preferably controlled at 30~70 DEG C；
（3）Sand, stone material should be preheated using dicang, and heating temperature is preferably controlled at 5~20 DEG C；
The out-of-machine temperature T of concretecIt can be calculated as the following formula with the temperature relation of raw material：
Tc= ΣTiWc/ΣWc
In formula：TcThe out-of-machine temperature of concrete mix（℃）；TiThe respective temperature of concrete raw material（℃）；
WiThe folk prescription dosage of concrete raw material（kg）；WcThe heat equivalent of concrete raw material（kJ/℃）, concrete when calculating
The specific heat c of raw material（KJ/kgK), cement, sand, stone, admixture take 0.84, and water and liquid water-reducing agent take 4.2.
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| CN112028561A (en) * | 2020-07-21 | 2020-12-04 | 甘肃省地震局（中国地震局兰州地震研究所） | Preparation method and surface spraying process of C40 inorganic coating anti-freeze concrete |
| CN112916807A (en) * | 2021-01-21 | 2021-06-08 | 重庆大学 | Preparation method of freezing mold core |
| CN113501688A (en) * | 2021-05-17 | 2021-10-15 | 中铁二十一局集团第二工程有限公司 | Antifreezing ready-mixed concrete without adding concrete antifreezing agent and processing method thereof |
| CN113529781A (en) * | 2021-08-12 | 2021-10-22 | 中国电建集团昆明勘测设计研究院有限公司 | Method for preventing large-volume concrete of fan foundation from cracking under low-temperature condition by multiple measures |
| CN114031353A (en) * | 2021-12-27 | 2022-02-11 | 中国核工业二四建设有限公司 | Neutron radiation prevention boron carbide concrete and preparation method thereof |
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| CN113529781A (en) * | 2021-08-12 | 2021-10-22 | 中国电建集团昆明勘测设计研究院有限公司 | Method for preventing large-volume concrete of fan foundation from cracking under low-temperature condition by multiple measures |
| CN114031353A (en) * | 2021-12-27 | 2022-02-11 | 中国核工业二四建设有限公司 | Neutron radiation prevention boron carbide concrete and preparation method thereof |
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