CN111499228B

CN111499228B - Cementing material for mortar and application thereof

Info

Publication number: CN111499228B
Application number: CN202010163268.2A
Authority: CN
Inventors: 温国平; 赵智利; 杨兑亨; 杨志江; 贺献年; 杨海; 申智磊; 杨永钢; 王军卫
Original assignee: Shexian County Qingzhang Cement Manufacturing Co ltd
Current assignee: Shexian County Qingzhang Cement Manufacturing Co ltd
Priority date: 2020-03-10
Filing date: 2020-03-10
Publication date: 2021-11-02
Anticipated expiration: 2040-03-10
Also published as: CN111499228A

Abstract

The invention provides a cementing material for mortar and application thereof, belonging to the field of solid waste resource utilization and building materials, and the preparation method of the cementing material for mortar comprises the following steps: carrying out doping pretreatment on steel slag particles, wherein the fineness of the particles is 0.35mm, and the screen residue is less than 3%; subjecting the pretreated steel slag particles to mechanical pulse to prepare steel slag powder, wherein the particle size distribution of the steel slag powder is as follows: 5-35% of less than or equal to 15 μm, 40-75% of less than or equal to 45 μm and 92-97% of less than or equal to 60 μm; and mixing and grinding the steel slag powder, the blast furnace slag micro powder and the gypsum to obtain the cementing material. The cementing material prepared by the invention has the advantages of fast early hydration reaction, high strength, low self-shrinkage rate, strong volume stability, and excellent anti-cracking performance and freeze-thaw resistance; the high-volume concrete pump has the advantages of high mixing amount, small slump, good pumping performance and purification capacity; the cement is used in mortar to replace Portland cement and has low cement consumption and low production cost.

Description

Cementing material for mortar and application thereof

Technical Field

The invention belongs to the field of solid waste resource utilization and building materials, and particularly relates to a cementing material for mortar and application thereof.

Background

The metallurgical solid waste is generated in the production process of the metallurgical industry. Solid wastes, i.e., metallurgical solid wastes, are mainly blast furnace slag, steel slag, non-ferrous slag (generated in non-ferrous metal smelting processes, such as copper slag, lead slag, zinc slag, nickel slag, etc.), red mud (generated in alumina refining process from bauxite), iron oxide slag (generated in steel rolling process), etc. generated in an iron-making furnace. Most steel tailings after the steel mill is fully iron-selected contain about 3% of residual metallic iron and contain higher divalent metal ions than cement clinker. In 2016, the discharge amount of steel slag in China is about 1 hundred million tons, the discharge amount of magnesium slag exceeds 600 million tons, the utilization rate is less than 30 percent, and the long-term large accumulation of the steel slag and the magnesium slag not only occupies a large amount of land resources, but also causes serious ecological damage and environmental pollution. Therefore, how to treat the industrial solid wastes and improve the comprehensive utilization rate of the industrial solid wastes, and then explore a new way for high-added-value recycling of the metallurgical solid wastes such as steel slag, magnesium slag and the like, and have important significance on the sustainable development of the metallurgy and steel industry in China.

Research shows that the ground steel slag powder, blast furnace slag powder, phosphorus slag powder, manganese slag and the like can be used as concrete admixture to prepare concrete meeting requirements. In addition, the steel slag, the blast furnace slag, the phosphorous slag and the manganese slag are also used for cement production and can prepare composite cement with special performance, and although the cement has the defect of early retardation compared with common portland cement, the later strength of the cement can reach the standard and has better performances of corrosion resistance, durability, heat resistance and the like.

The cement industry belongs to the high energy consumption and high pollution industry, and the cement not only consumes a large amount of non-renewable energy sources and resources such as coal, limestone, clay and the like, but also discharges a large amount of dust and SO in the production process₂And CO₂And the like, causing a large amount of resource consumption and serious environmental pollution. Therefore, the solid waste is used for replacing part of cement to prepare the cementing material, the cement yield is reduced, the resources are saved, the environmental quality is improved, and the method becomes an effective way for sustainable development of the cement industry.

Disclosure of Invention

The invention aims to provide a novel water-soluble polyurethane emulsion which has the advantages of quick early hydration reaction, high strength, low self-shrinkage rate, strong volume stability, excellent anti-cracking performance and excellent freeze-thaw resistance; the preparation method of the cementing material for the mortar has the advantages of high mixing amount, small slump, good pumping performance and purification capacity, and the prepared cementing material is used for replacing portland cement in the mortar so as to reduce the using amount of the cement and the production cost.

The technical scheme adopted by the invention for realizing the purpose is as follows:

a preparation method of a cementing material for mortar comprises the following steps:

carrying out doping pretreatment on steel slag particles, wherein the fineness of the particles is 0.35mm, and the screen residue is less than 3%;

subjecting the pretreated steel slag particles to mechanical pulse to prepare steel slag powder, wherein the particle size distribution of the steel slag powder is as follows: 5-35% of the content of less than or equal to 15 mu m, 40-75% of the content of less than or equal to 45 mu m and 92-97% of the content of less than or equal to 60 mu m; and the number of the first and second groups,

and (3) mixing and grinding the steel slag powder, the blast furnace slag micro powder and the gypsum to obtain the cementing material.

The steel slag and the blast furnace slag are used as raw materials, and are prepared into the cementing material by being supplemented with the industrial byproduct desulfurized gypsum, the cementing material can partially or completely replace portland cement, the cement usage amount is reduced, the production cost of the high-strength concrete is reduced, and the beneficial effects of energy conservation and emission reduction can be achieved. The steel slag powder provides different particle sizes, wherein the powder with smaller particle size has larger specific surface area, is beneficial to the rapid occurrence of hydration reaction, and can improve the early strength of mortar or concrete; in addition, the powder with different grain diameters can increase the using amount of the cementing material in the mortar, or can improve the strength of the mortar or concrete on the premise of the same using amount.

In some embodiments, the medium in the doping pretreatment step is ammonium acetate with a concentration of 2.5mol/L, and the doping agent is added in an amount of 3-8% of the steel slag particles. The steel slag is doped and pretreated firstly, so that the surface and the structure of the steel slag can be damaged in advance, the steel slag is loaded with the doping agent, the purifying capacity of the cementing material is endowed, and on the premise of not generating negative influence on the cementing performance, the cementing material or mortar or concrete using the cementing material has the capacity of degrading pollutants in water, so that the steel slag has higher application value.

In some embodiments, the dopant comprises ammonium tungstate, cerium oxide, sodium fluorozirconate, and sodium 3-nitrobenzenesulfonate in a weight ratio of 15-30:5-10:1-1.5: 1. The doping agent endows the gelled material with purification capacity, and additionally, the sodium fluorozirconate and the 3-sodium nitrobenzenesulfonate can accelerate the occurrence of a first hydration heat peak, accelerate the generation of ettringite, improve the early strength of mortar, and simultaneously generate an unexpected effect by cooperation among the doping agents; because the self-shrinkage rate is reduced, the hardened structure has strong volume stability, and can deal with and contain the damage of the micro structure of mortar or concrete under the freeze-thaw condition, after the concrete is subjected to freeze-thaw cycles for 300 times, the relative dynamic elastic modulus is kept above 85%, the mass loss rate is lower than 2.8%, and the concrete shows excellent freeze-thaw resistance.

In some embodiments, the specific operations of the doping pretreatment are: stirring the doping raw materials in a mode of alternately carrying out slow stirring and fast stirring, wherein the stirring time is 12-16 h; the slow stirring speed is 400-600r/min, and the time is 90-120 min; the rapid stirring rate is 800-.

In some embodiments, the pretreated steel slag particles are ground by a grinding device such that the particles are subjected to mechanical impulses to form powders of different particle size distributions.

In some preferred embodiments, the iron particles in the steel slag are removed in real time during the mechanical pulse process, so that the iron content in the steel slag powder is not more than 1 wt%. The real-time removal of iron particles can avoid the abrasion of the iron particles on equipment and can also reduce the grinding energy consumption.

In some embodiments, the powder specific surface area of the blast furnace slag micro powder is 450-²In terms of/kg. Preferably, the blast furnace slag is water-quenched granulated blast furnace slag, water-quenched manganese slag or water-quenchedOne or more of nickel-iron slag and magnesium slag.

In some embodiments, the chemical composition of the gypsum is: CaO is more than or equal to 40%, SO₃15-25wt%, and the specific surface area is 350-400m²/kg。

In some embodiments, the contents of the steel slag powder, the blast furnace slag micropowder and the gypsum in the cementing material are respectively as follows by weight percent: 40-60%, 35-45% and 5-10%.

In some embodiments, the mixing and milling time of each raw material of the cement material is 30-60 min.

The invention also provides the application of the cementing material for the mortar prepared by the method in the mortar, wherein the substitution degree of the cementing material in the mortar for the Portland cement is 0.1-100%; preferably, the degree of substitution is 40-75%.

The invention also provides a method for preparing mortar by using the solid waste cementing material, which comprises the following steps:

-preparing a cementitious material for mortar according to the above method;

uniformly mixing the cementing material, the cement, the fly ash, the aggregate and the water reducing agent, adding water, and mixing to obtain the mortar. The obtained mortar has the advantages of fast early hydration, high strength, higher strength in the later period of condensation, lower shrinkage rate of the mortar, excellent anti-cracking performance and freeze-thaw resistance, and good water resistance, is used for mutual bonding between stones, between stones and ceramics, between ceramics and between ceramics, and can also be used for bonding stones or ceramics on the surface of a cement base.

In some embodiments, the mortar comprises the following raw materials in parts by weight: 0-10 parts of cement, 0-10 parts of cementing material, 0-8 parts of fly ash, 70-75 parts of aggregate and 1-5 parts of water reducing agent.

In some embodiments, the compressive strength of mortars 3d and 7d is increased by 15-30% and 10-25% respectively over mortars without cementitious material. The early strength is improved, so that the early hydration reaction is good, the damaged surface of the small-particle-size powder is easier to excite the reaction activity, and more Ca is provided²⁺And promote the formation of early hydration product ettringite.

In some embodiments, the mortar produces concrete having a strength of C80-C150.

The invention has the beneficial effects that:

the cementing material prepared by utilizing metallurgical solid wastes and industrial byproducts can greatly reduce the using amount of Portland cement, has high waste utilization rate, and has the advantages of cost saving, energy conservation and emission reduction; the cementing material has the advantages of rapid hydration reaction, rapid early strength improvement, low self-shrinkage rate, higher later strength, strong volume stability, small slump, good pumping performance and freeze-thaw resistance; the cementing material can provide high strength performance when being used in mortar, and the strength of the prepared concrete can reach C80-C150.

The invention adopts the technical scheme to provide the cementing material for the mortar and the application thereof, makes up the defects of the prior art, and has reasonable design and convenient operation.

Drawings

FIG. 1 is a schematic diagram of a temperature change curve of mortar in a hydration reaction time of 18 h;

FIG. 2 is a graph showing the change of the volume shrinkage rate of the mortar in 48 h.

Detailed Description

The technical solution of the present invention is further described in detail below with reference to the following detailed description and the accompanying drawings:

In some preferred embodiments, the iron particles in the steel slag are removed in real time during the mechanical pulse process, so that the iron content in the steel slag powder is not more than 1 wt%. The real-time removal of iron particles can avoid the abrasion of the iron particles on equipment and can also reduce the grinding energy consumption. Preferably, the steel slag powder contains C as main component₃S 10-45％，C₂S 10-40％，CaOH 1-5％，CaCO₃3-8％，CaO 1-3％，SiO₂ 0.5-5％，Al₂O₃ 0.1-3％，MgCO₃ 2-5％，MgO 2-5％，MnO 0.1-2％，FeO 0.5-3％。

In some embodiments, the powder specific surface area of the blast furnace slag micro powder is 450-²In terms of/kg. Preferably, the blast furnace slag is one or a combination of water-quenched granulated blast furnace slag, water-quenched manganese slag, water-quenched nickel-iron slag and magnesium slag. Preferably, the main component and content of the blast furnace slag micro powder are CaO₃ 5-53％，SiO₂ 20-40％，Al₂O₃ 3-15％，MgO 2-15％，MnO 0.1-5％，FeO 0.1-2.5％，S 0.1-1％。

In other preferred embodiments, 0.1-1 wt% of a retarder is added to the cementitious material, wherein the retarder comprises sodium glycerophosphate and hexahydrophthalic anhydride in a weight ratio of 1-2: 1. The retarder can delay the process that the calcium ion concentration reaches supersaturation, prolong the hydration induction period, delay the occurrence time of a second hydration heat peak, improve the hydration rate of the cementing material, and enable the product ettringite and C-S-H gel to be interpenetrated to form a compact structure, wherein the retarder also exists, so that the hydration heat peak value can be reduced, the reduction of later-stage compactness and strength caused by pores left by rapid evaporation of water is avoided, and the effects of temperature control and crack prevention are achieved; the compactness of the mortar or concrete structure is improved, so that acidic gases such as carbon dioxide and the like are difficult to enter the concrete structure through the capillary holes, the carbonization depth is effectively reduced, and the carbonization resistance of the mortar or concrete is improved.

In other embodiments, the cementing material further comprises 0-10 wt% of an additive, wherein the additive is selected from one or a combination of more of fly ash, diatomite and red mud.

In other preferred embodiments, the cement further comprises 0-4 wt% of an activator, wherein the activator is selected from one or more of calcium oxide, calcium silicate and calcium aluminate.

-preparing a cementitious material for mortar according to the above method;

uniformly mixing the cementing material, the cement, the fly ash, the aggregate and the water reducing agent, adding water, and mixing for 3-20min to obtain the mortar. The obtained mortar has the advantages of fast early hydration, high strength, higher strength in the later period of condensation, lower shrinkage rate of the mortar, excellent anti-cracking performance and freeze-thaw resistance, and good water resistance, is used for mutual bonding between stones, between stones and ceramics, between ceramics and between ceramics, and can also be used for bonding stones or ceramics on the surface of a cement base.

It is to be understood that the foregoing description is to be considered illustrative or exemplary and not restrictive, and that changes and modifications may be made by those skilled in the art within the scope and spirit of the appended claims. In particular, the present invention covers other embodiments having any combination of features from the different embodiments described above and below, without the scope of the invention being limited to the specific examples below.

Example 1:

(1) adding 6 times of ammonium acetate with the weight and the concentration of 2.5mol/L into steel slag particles, sending the mixture into stirring equipment for stirring reaction for 4 hours, then adding a doping agent with the weight accounting for 3.5 percent of the steel slag particles, slowly stirring at the speed of 400r/min for 90 minutes and quickly stirring at the speed of 800r/min for 120 minutes alternately for 12 hours, and drying at 130 ℃ to obtain the treated steel slag particles, wherein the doping agent comprises ammonium tungstate, cerium oxide, sodium fluorozirconate and 3-nitrobenzenesulfonic acid sodium salt, the weight ratio of the ammonium tungstate to the cerium oxide to the sodium fluorozirconate to the sodium fluoronitrobenzene sulfonate is 30:9.5:1.5:1, the fineness of the particles is 0.35mm, the screen residue is less than 3 percent, and the main components and the content of the steel slag powder are C₃S 39.8％，C₂S 38.4％，CaOH 3.4％，CaCO₃ 3.8％，CaO 1.3％，SiO₂ 3.6％，Al₂O₃1.5％，MgCO₃ 3.3％，MgO 2.4％，MnO 1.2％，FeO 1.3％；

(2) Grinding the pretreated steel slag particles, and removing iron particles in the steel slag in real time during grinding to ensure that the iron content in the obtained steel slag powder is not more than 1 wt%, thereby preparing the steel slag powder, wherein the particle size distribution of the powder is as follows: the proportion of less than or equal to 15 mu m is 35 percent, the proportion of less than or equal to 45 mu m is 73 percent, and the proportion of less than or equal to 60 mu m is 96 percent;

(3) respectively taking 53 wt%, 40 wt% and 7 wt% of steel slag powder, water-quenched granulated blast furnace slag micro powder and gypsum, and carrying out mixed grinding for 45min to obtain the cementing material, wherein the powder specific surface area of the water-quenched granulated blast furnace slag micro powder is 560m²Per kg, its main component and content are CaO₃ 41.4％，SiO₂ 36.7％，Al₂O₃10.3%, MgO 7.4%, MnO 1.4%, FeO 2.3%, and S0.8%, wherein the chemical components of the gypsum are as follows: CaO is more than or equal to 40%, SO₃15 wt% and a specific surface area of 400m²/kg。

A method for preparing mortar by utilizing solid waste cementing materials comprises the following steps:

(1) preparing a cementing material for mortar according to the method;

(2) and 3.5 parts of cement, 6.5 parts of cementing material, 2.5 parts of fly ash, 70 parts of aggregate and 1.5 parts of water reducing agent are taken according to the proportion and mixed evenly, water is added and mixed for 20min, and the mortar is obtained.

Example 2:

the preparation method of the cementing material for the mortar is different from the preparation method of the cementing material in example 1 in that:

and (3) taking 48 wt% of steel slag powder, 32 wt% of water-quenched granulated blast furnace slag micro powder, 7.5 wt% of gypsum, 5.5 wt% of diatomite and 7 wt% of calcium oxide according to the proportion as the cementing material.

The difference between the method for preparing mortar by using solid waste cementing materials and the embodiment 1 is that:

in the step (2), the raw materials for the mortar comprise 0 part of cement, 10 parts of cementing material, 3.5 parts of fly ash, 70 parts of aggregate and 2 parts of water reducing agent.

Example 3:

the doping agent in the step (1) comprises ammonium tungstate, cerium oxide, sodium fluorozirconate and 3-nitrobenzenesulfonic acid sodium salt, and the weight ratio of the doping agent to the doping agent is 23.5:8.5:1: 1;

the particle size distribution of the steel slag powder in the step (2) is as follows: the proportion of less than or equal to 15 mu m is 33 percent, the proportion of less than or equal to 45 mu m is 68 percent, and the proportion of less than or equal to 60 mu m is 93 percent;

(3) respectively taking the steel slag powder, the water-quenched granulated blast furnace slag micro powder, the gypsum and the retarder according to the proportion of 53.7 wt%, 38.5 wt%, 7.5 wt% and 0.3 wt%, and carrying out mixed grinding for 30-60min to obtain the cementing material, wherein the retarder comprises sodium glycerophosphate and hexahydrophthalic anhydride according to the weight ratio of 1.5: 1.

A method for preparing mortar by using solid waste cementing materials, which is the same as the steps and parameters of the embodiment 1 to prepare the mortar.

Example 4:

a method for preparing mortar comprises the following steps: and (2) uniformly mixing 10 parts of cement, 0 part of the cementing material prepared in example 1, 2.5 parts of fly ash, 70 parts of aggregate and 1.5 parts of water reducing agent according to the proportion, adding water, and mixing for 20min to obtain the mortar.

Comparative example 1:

the grain size of the steel slag powder in the step (2) is controlled to be 75 mu m, and the screen residue is less than 3 percent.

Comparative example 2:

the grain diameter of the steel slag powder in the step (2) is controlled to be 30 mu m, and the screen residue is less than 3 percent.

Comparative example 3:

the doping agent in the step (1) comprises ammonium tungstate, cerium oxide and sodium fluorozirconate, and 3-nitrobenzene sodium sulfonate is not added.

Comparative example 4:

the doping agent in the step (1) comprises ammonium tungstate, cerium oxide and 3-nitrobenzenesulfonic acid sodium salt, and sodium fluozirconate is not added.

Comparative example 5:

the doping agent in the step (1) comprises ammonium tungstate and cerium oxide, and sodium fluozirconate and 3-nitrobenzene sodium sulfonate are not added.

Comparative example 6:

the retarder in the step (3) is sodium glycerophosphate, and no hexahydrophthalic anhydride is added.

Comparative example 7:

in the step (3), the retarder is hexahydrophthalic anhydride and sodium glycerophosphate is not added.

Test example 1:

compressive strength and slump test of mortar

The test method comprises the following steps: the slurries prepared in examples 1 to 4 and comparative examples 1 to 7 were each charged into a 40mm by 160mm mold and subjected to vibration molding. And (3) curing the test piece for 1d at the temperature of 30 ℃ and the humidity of more than or equal to 90%, and demolding. And then maintaining at 30 ℃ and humidity of more than or equal to 90% until the cement mortar is aged for 3d, 7d and 28d, testing the compressive strength according to GB/T17671-1999 cement mortar compressive strength test method (ISO method), and measuring the slump by using a slump cone method. The results are shown in table 1 below.

TABLE 1 compression Strength and slump test results of mortar

As can be seen from the above table, the differences in compressive strength and slump between examples 1, 2 and 4 are not obvious, which indicates that the cementing material of the invention can partially or completely replace cement, does not negatively affect the performance of mortar or concrete, can reduce the consumption of cement, and can reduce the production cost in actual production.

Example 1 compared to comparative examples 1 and 2, comparative example 1 had the greatest slump and, although having good pumping performance, had the worst early strength indicating poor early hydration; comparative example 3 has the highest early strength and the best hydration reaction, but has the lowest slump, which is not beneficial to pumping and mixing; the slump and the early strength of the concrete are between those of the concrete in the embodiment 1, and the concrete has higher early strength and good pumping performance, and has more advantages and application prospects in actual production.

The slump difference between the example 1 and the comparative examples 3-5 is not obvious, but the compressive strength difference is obvious, the 28d strength of the comparative examples is poorer than that of the example 1, the early strength of the comparative examples 4 and 5 is the worst, the comparative example 3 is slightly increased, but the increase degree is lower than that of the example 1, and the comprehensive results show that the sodium fluorozirconate and the sodium 3-nitrobenzenesulfonate added into the doping agent in the example 1 can synergistically exert beneficial effects, can accelerate the early hydration reaction process, promote the generation of early hydration product ettringite, and improve the early strength of mortar or concrete.

The early strength and slump difference of the examples 1 and 3 and the comparative examples 6 and 7 are not obvious, but the 28d strength of the example 3 is obviously improved compared with the 28d strength of the example 1, and the 28d strength of the comparative examples 6 and 7 is not much different from the 28d strength of the example 1 and is slightly reduced, so that the addition of the retarder sodium glycerophosphate and hexahydrophthalic anhydride in the example 3 can synergistically prolong the hydration induction period, so that the hydration rate of the cementing material is improved, and the structural compactness and the later strength of mortar or concrete are improved.

Test example 2:

hydration test of mortar

The test method comprises the following steps: the same amount of the mortar obtained in examples 1, 3 and 4 and comparative example 5 was taken, the two ends of the thermocouple temperature measuring wire were twisted together and inserted into the center of the mortar, and then placed in an incubator, the joints were inserted into an automatic temperature recorder, and the data was read after 18 hours, with the results shown in fig. 1.

FIG. 1 is a schematic diagram of a temperature change curve of the mortar in a hydration reaction time of 18 h. As can be seen from the figure, the mortars of examples 1, 3 and 4 showed the first exothermic peak within 40-65min, the peak temperatures were 43 ℃ and 45 ℃ respectively, and 44 ℃, and the mortar of comparative example 5 showed the first exothermic peak within 60-75min, the peak temperatures were 43 ℃ respectively.

Examples 1 and 4 and comparative example 5 showed a second exothermic peak at 330-; the beneficial effects of the sodium fluorozirconate and the 3-nitrobenzenesulfonic acid sodium salt added into the dopant in the embodiment 1 can be synergistically exerted, the early hydration reaction process can be accelerated, and the generation of early hydration product ettringite is promoted; in the embodiment 3, the addition of the retarder sodium glycerophosphate and the hexahydrophthalic anhydride can synergistically prolong the hydration induction period and delay the occurrence time of the second hydration heat peak, so that the hydration rate of the cementing material is improved, the hydration heat peak value can be reduced, the reduction of later-stage compactness and strength caused by pores left by rapid evaporation of water is avoided, and the effects of temperature control and crack prevention are achieved.

Test example 3:

shrinkage test of mortar

The test method comprises the following steps: the slurries prepared in examples 1 and 4 and comparative examples 3, 4 and 5 were put into 40mm × 40mm × 160mm molds, respectively, and were subjected to vibration molding. And (3) curing the test piece for 1d at the temperature of 30 ℃ and the humidity of more than or equal to 90%, and demolding. And then curing the concrete at the temperature of 30 ℃ and the humidity of more than or equal to 90%, and performing shrinkage test on the concrete according to a non-contact method in a concrete shrinkage test method in the test method standard for the long-term performance and the durability of common concrete (standard No. GB/T50082-2009), wherein the test result is shown in figure 2.

FIG. 2 is a graph showing the change of the volume shrinkage rate of the mortar in 48 h. As can be seen from the figure, the shrinkage rate of the test block is increased along with the increase of the curing age, but the increase range is gradually reduced, and the test block is slightly expanded, and the shrinkage rate is gradually increased to a more stable stage from 6 hours later to 36 hours later. The shrinkage change amplitude of the embodiment 1 is the smallest, the trend changes of the embodiment 4 and the comparative example 3 are relatively close, and the fluctuation trend of the comparative examples 4 and 5 is the largest; the sodium fluorozirconate and the 3-nitrobenzenesulfonic acid sodium salt added into the doping agent in the embodiment 1 can exert the beneficial effects synergistically, reduce the shrinkage rate of mortar or concrete, prevent cracks caused by self-shrinkage and enhance the volume stability of the hardened structure.

Test example 4:

freeze-thaw resistance test of mortar

The test method comprises the following steps: the slurries prepared in examples 1 and 4 and comparative examples 3, 4 and 5 were put into 40mm × 40mm × 160mm molds, respectively, and were subjected to vibration molding. And (3) curing the test piece for 1d at the temperature of 30 ℃ and the humidity of more than or equal to 90%, and demolding. And then, maintaining the concrete at the temperature of 30 ℃ and the humidity of more than or equal to 90 percent until the concrete reaches the age of 28d, and carrying out experimental study according to a rapid freezing and thawing method in the test method standard for the long-term performance and the durability of common concrete (standard number GB/T50082-2009) for 300 times of rapid freezing and thawing cycles, wherein the results are shown in the following table 2.

TABLE 2 Freeze thaw resistance test results for mortar

Standard requirements

Example 1

Example 4

Comparative example 3

Comparative example 4

Comparative example 5

Modulus of relative kinetic elasticity

≥60％

88.3％

86.5％

79.5％

85.3％

78.1％

Mass loss rate

≤5％

2.6％

3.3％

4.2％

3.6％

4.1％

As can be seen from the above table, the results all meet the standard requirements, but the result of example 1 is optimal, the difference between comparative examples 3 and 5 is not obvious, and comparative example 4 is improved to some extent, but the amplitude is not large; the sodium fluorozirconate and the sodium 3-nitrobenzenesulfonate added into the doping agent in the embodiment 1 can exert the beneficial effects synergistically, and can enhance the freeze-thaw resistance of mortar or concrete, so that the mortar or concrete can show excellent durability.

Test example 5:

mortar anti-carbonation test

The test method comprises the following steps: the slurries prepared in examples 1, 3 and 4 and comparative examples 6 and 7 were put into 40mm × 40mm × 160mm molds, respectively, and were subjected to vibration molding. And (3) curing the test piece for 1d at the temperature of 30 ℃ and the humidity of more than or equal to 90%, and demolding. And then, maintaining the test piece to 28d age at the temperature of 30 ℃ and the humidity of more than or equal to 90 percent, and testing the carbonization depth of the test piece at 28 age. The results are shown in table 3 below.

TABLE 3 anti-carbonation test results for the mortar

	Test results	Grade
			Example 1	10.3	T-III
Example 3	6.7	T-Ⅳ
			Example 4	9.3	T-Ⅳ
Comparative example 6	8.9	T-Ⅳ
			Comparative example 7	10.6	T-Ⅳ

As can be seen from the above table, the carbonization depth of the concrete in example 3 is the lowest, and the difference between the concrete in example 1 and the concrete in comparative example 6 is not obvious, which shows that the addition of the retarder sodium glycerophosphate and hexahydrophthalic anhydride in example 3 can synergistically reduce the carbonization depth, improve the carbonization resistance of mortar or concrete, and enable the mortar or concrete to show excellent durability.

Conventional techniques in the above embodiments are known to those skilled in the art, and therefore, will not be described in detail herein.

The above embodiments are merely illustrative, and not restrictive, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention, and the protection scope of the present invention should be defined by the claims.

Claims

1. A preparation method of a cementing material for mortar comprises the following steps:

subjecting the pretreated steel slag particles to mechanical pulse to prepare steel slag powder, wherein the particle size distribution of the powder is as follows: 5-35% of the content of less than or equal to 15 mu m, 40-75% of the content of less than or equal to 45 mu m and 92-97% of the content of less than or equal to 60 mu m; and the number of the first and second groups,

mixing and grinding the steel slag powder, the blast furnace slag micro powder and the gypsum to obtain a cementing material;

the medium used in the doping pretreatment step is ammonium acetate with the concentration of 2.5mol/L, and the additive amount of the doping agent is 3-8% of the steel slag particles; the doping agent comprises ammonium tungstate, cerium oxide, sodium fluorozirconate and 3-nitrobenzenesulfonic acid sodium salt, and the weight ratio of the ammonium tungstate to the cerium oxide to the sodium fluorozirconate to the 3-nitrobenzenesulfonic acid sodium salt is 15-30:5-10:1-1.5: 1.

2. The preparation method of the cementing material for mortar according to claim 1, which is characterized in that: the specific operation of the doping pretreatment is as follows: stirring the doping raw materials in a mode of alternately carrying out slow stirring and fast stirring, wherein the stirring time is 12-16 h; the slow stirring speed is 400-600r/min, and the time is 90-120 min; the rapid stirring speed is 800-1000r/min, and the time is 90-120 min.

3. The preparation method of the cementing material for mortar according to claim 1, which is characterized in that: the powder specific surface area of the blast furnace slag micro powder is 450-600m²/kg。

4. The preparation method of the cementing material for mortar according to claim 1, which is characterized in that: the chemical components of the gypsum are as follows: CaO is more than or equal to 40%, SO₃15-25wt%, and the specific surface area is 350-400m²/kg。

5. Use of a cementitious material for mortars, obtained by the method according to any one of claims 1 to 4, in mortars, the cementitious material having a degree of substitution of Portland cement in the mortars comprised between 0.1 and 100%.

6. A method for preparing mortar by utilizing solid waste cementing materials comprises the following steps:

-preparing a cementitious material for mortars according to the process of any one of claims 1 to 4;

uniformly mixing the cementing material, the cement, the fly ash, the aggregate and the water reducing agent, adding water, and mixing to obtain the mortar.

7. The method for preparing mortar by using the solid waste cementing material according to claim 6, which is characterized in that: the mortar comprises the following raw materials in parts by weight: 0-10 parts of cement, 0-10 parts of cementing material, 0-8 parts of fly ash, 70-75 parts of aggregate and 1-5 parts of water reducing agent, wherein the cement and the cementing material are not 0 at the same time.

8. The method for preparing mortar by using the solid waste cementing material according to claim 6, which is characterized in that: the compressive strength of the mortar 3d and 7d is respectively improved by 15-30% and 10-25% compared with the mortar without the cementing material.