阅读说明：本技术 缓凝剂、碱激发矿渣-粉煤灰砂浆及其胶凝材料 (Retarder, alkali-activated slag-fly ash mortar and cementing material thereof ) 是由 张祖华 许闯 史才军 于 2020-03-04 设计创作，主要内容包括：本发明涉及建筑材料添加剂,公开了一种缓凝剂,以所述缓凝剂的总重量为基准,所述缓凝剂含有40-100重量％的碱金属盐和0-60重量％的碱土金属盐；其中,所述碱金属盐选自碳酸钠、磷酸钠和硼酸钠中的一种或多种；所述碱土金属盐选自氯化钡、硝酸钙和硼酸钡中的一种或多种。本发明还公开了一种用于制备碱激发矿渣-粉煤灰基胶凝材料的碱激发矿渣-粉煤灰砂浆以及由碱激发矿渣-粉煤灰砂浆得到的碱激发矿渣-粉煤灰基胶凝材料。所述缓凝剂能够减缓凝胶材料的凝结,同时能够保证凝胶材料的强度和耐久性,而且原材料价格便宜,可以现配现用,适合现场大量使用。(The invention relates to a building material additive, and discloses a retarder, which comprises 40-100 wt% of alkali metal salt and 0-60 wt% of alkaline earth metal salt based on the total weight of the retarder; wherein the alkali metal salt is selected from one or more of sodium carbonate, sodium phosphate and sodium borate; the alkaline earth metal salt is selected from one or more of barium chloride, calcium nitrate and barium borate. The invention also discloses alkali-activated slag-fly ash mortar for preparing the alkali-activated slag-fly ash-based cementing material and the alkali-activated slag-fly ash-based cementing material obtained from the alkali-activated slag-fly ash mortar. The retarder can slow down the coagulation of the gel material, can ensure the strength and durability of the gel material, has low price of raw materials, can be prepared at present, and is suitable for being used in large quantities on site.)

1. A retarder, characterized in that the retarder comprises 40-100 wt% of alkali metal salt and 0-60 wt% of alkaline earth metal salt, based on the total weight of the retarder;

wherein the alkali metal salt is selected from one or more of sodium carbonate, sodium phosphate and sodium borate; the alkaline earth metal salt is selected from one or more of barium chloride, calcium nitrate and barium borate.

2. The set retarder of claim 1, comprising 40 to 99 wt% of an alkali metal salt and 1 to 60 wt% of an alkaline earth metal salt, based on the total weight of the set retarder.

3. The retarder of claim 2, comprising 40-70 wt% of an alkali metal salt, 5-25 wt% of an alkaline earth metal salt, and 25-35 wt% of a polyol-based shrinkage reducing agent and/or polyether-based shrinkage reducing agent, based on the total weight of the retarder.

4. An alkali-activated slag-fly ash mortar for preparing an alkali-activated slag-fly ash-based cementitious material, characterized in that the slurry contains, in weight percent, 15-30% of slag and 70-85% of fly ash;

in addition, the gel material also contains 3 to 8 percent of alkaline activator, 4 to 8 percent of retarder and 26 to 50 percent of water based on the total weight of the slag and the fly ash;

wherein the retarder is the retarder of any one of claims 1-3.

5. The alkali-activated slag-fly ash mortar for producing an alkali-activated slag-fly ash-based cementitious material according to claim 4, wherein the slag has a particle size of 1 to 45 μm and the fly ash has a particle size of 1 to 100 μm.

6. The alkali-activated slag-fly ash mortar for producing an alkali-activated slag-fly ash-based cementitious material according to claim 4, wherein the alkali activator is a mixture of alkali and an alkali metal silicate;

the alkali is sodium hydroxide and/or potassium hydroxide, and the alkali metal silicate is sodium silicate and/or potassium silicate.

7. The alkali-activated slag-fly ash mortar for producing an alkali-activated slag-fly ash-based cementitious material according to claim 6, wherein the mass ratio of the alkali to the alkali metal silicate is 1: 0.5-3.

8. The alkali-activated slag-fly ash mortar for producing an alkali-activated slag-fly ash-based cementitious material according to claim 4, wherein the cementitious material further contains an aggregate in an amount of 160-200% by weight based on the total weight of the above-mentioned slag and fly ash.

9. An alkali-activated slag-fly ash-based cementitious material, characterized in that the cementitious material is obtained by curing and maintaining the alkali-activated slag-fly ash mortar according to any one of claims 4 to 8.

10. The alkali-activated slag-fly ash-based cementitious material of claim 9, wherein the method of preparing the alkali-activated slag-fly ash mortar comprises:

(1) respectively providing an alkaline excitant aqueous solution and a retarder aqueous solution;

dissolving an alkaline activator in water, sealing and standing for 12-48h to obtain an alkaline activator aqueous solution;

dissolving a retarder in water to obtain a retarder water solution;

(2) and (2) uniformly mixing the alkaline excitant aqueous solution, the retarder aqueous solution, the slag, the fly ash and the selectively added aggregate in the step (1) to obtain the alkaline excitant slag-fly ash mortar.

Technical Field

The invention relates to a building material additive, in particular to a retarder, alkali-activated slag-fly ash mortar and a cementing material thereof.

Background

Cement plays a very important role in global infrastructure as a common building material. The production of cement consumes a large amount of natural resources (such as limestone, clay and the like) and energy, and discharges a large amount of greenhouse gases, which increases the greenhouse effect of the earth and influences the living environment of the earth. Currently, various countries in the world are constantly striving to find ways to improve cement production to reduce energy consumption and greenhouse gas emissions. However, it has been found that this effect is not significant, since the energy saving techniques of cement production have almost come to the end of theory (extreme). Finding a sustainable alternative to cement for cementitious materials is currently considered the most effective technical approach to solve the above problems.

The alkali-activated cementing material has the following characteristics: on one hand, the solid waste discharged by other industries can be effectively utilized, and on the other hand, the defects of the Portland cement in certain properties (such as high temperature resistance and sulfate corrosion resistance) can be made up so as to meet the requirements of certain engineering fields. The alkali-activated cementing material is expected to become a substitute material for cement in various engineering fields by virtue of the advantages of low carbon emission, reasonable utilization of industrial solid wastes, equivalent or even better performance and the like, and is a focus of extensive researchers at present. However, the development of alkali-activated cements also faces some technical difficulties: the alkali-activated reaction of the slag has the characteristic of rapid setting, the initial setting time of the slag is generally 10-30min, the initial setting time of the cementing material which does not meet the conventional requirement of the cement industry is more than or equal to 45min, and the large-scale engineering application of the slag is hindered.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a retarder, alkali-activated slag-fly ash mortar and alkali-activated slag-fly ash-based cementing material, wherein the retarder can slow down the coagulation of a gel material, can ensure the strength and durability of the gel material, has low price of raw materials, can be prepared and used at present, and is suitable for large-scale field use.

In order to achieve the above object, the present invention provides in a first aspect a retarder comprising 40 to 100% by weight of an alkali metal salt and 0 to 60% by weight of an alkaline earth metal salt, based on the total weight of the retarder;

wherein the alkali metal salt is selected from one or more of sodium carbonate, sodium phosphate and sodium borate; the alkaline earth metal salt is selected from one or more of barium chloride, calcium nitrate and barium borate.

Preferably, the retarder contains 40-99 wt% of an alkali metal salt and 1-60 wt% of an alkaline earth metal salt, based on the total weight of the retarder.

Preferably, the retarder contains 40-70 wt% of alkali metal salt, 5-25 wt% of alkaline earth metal salt and 25-35 wt% of polyalcohol type shrinkage reducing agent and/or polyether type shrinkage reducing agent based on the total weight of the retarder.

In a second aspect, the present invention provides an alkali-activated slag-fly ash mortar for preparing an alkali-activated slag-fly ash-based cementitious material, the cementitious material containing, in weight percent, 15% to 30% of slag and 70% to 85% of fly ash;

in addition, the gel material also contains 3 to 8 percent of alkaline activator, 4 to 8 percent of retarder and 26 to 50 percent of water based on the total weight of the slag and the fly ash;

wherein the retarder is the retarder of the invention.

Preferably, the particle size of the slag is 1-45 μm, and the particle size of the fly ash is 1-100 μm.

Preferably, the alkali-activator is a mixture of an alkali and an alkali metal silicate;

the alkali is sodium hydroxide and/or potassium hydroxide, and the alkali metal silicate is sodium silicate and/or potassium silicate.

Further preferably, the mass ratio of the alkali to the alkali silicate is 1: 0.5-3.

Further preferably, the gel material further contains aggregate 160-200% of the total weight of the above slag and fly ash.

In a third aspect, the invention provides an alkali-activated slag-fly ash-based cementing material, which is obtained by curing and maintaining the alkali-activated slag-fly ash mortar.

Preferably, the method for preparing the alkali-activated slag-fly ash mortar comprises:

(1) respectively providing an alkaline excitant aqueous solution and a retarder aqueous solution;

dissolving an alkaline activator in water, sealing and standing for 12-48h to obtain an alkaline activator aqueous solution;

dissolving a retarder in water to obtain a retarder water solution;

(2) and (2) uniformly mixing the alkaline excitant aqueous solution, the retarder aqueous solution, the slag, the fly ash and the selectively added aggregate in the step (1) to obtain the alkaline excitant slag-fly ash mortar.

Through the technical scheme, the invention has the beneficial effects that:

1. the retarder provided by the invention can effectively prolong the gelation time of the alkali-activated slag-fly ash cementing material, the gelation time of the alkali-activated slag-fly ash cementing material can be adjusted within 1-12h by changing the addition amount, and the strength and hardness of the alkali-activated slag-fly ash cementing material can be ensured and even enhanced.

2. The retarder provided by the invention can delay the condensation of the alkali-activated slag-fly ash cementing material, simultaneously reduce the shrinkage of the alkali-activated slag-fly ash cementing material, prevent the surface from cracking due to large shrinkage, and is not beneficial to the practical application of the alkali-activated slag-fly ash cementing material.

3. The retarder provided by the invention can not obviously reduce the fluidity of the freshly mixed mortar, and even can improve the fluidity of the freshly mixed mortar, and the fluidity of the freshly mixed mortar meets the requirement, so that the retarder is beneficial to normal construction.

4. The retarder provided by the invention can be prepared and used at the moment, is simple to operate, has cheap raw materials, and is suitable for large-scale field use.

5. The alkali-activated slag-fly ash-based cementing material provided by the invention utilizes slag and fly ash industrial solid wastes as test raw materials, thereby not only solving the problem of land resource waste and pollution caused by long-term accumulation of slag (partial areas), fly ash and other industrial solid wastes, but also reducing the consumption of portland cement, reducing the energy consumption and environmental problems caused by cement production, and meeting the requirements of energy conservation, emission reduction and green low-carbon sustainable development.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In a first aspect, the present invention provides a retarder comprising 40 to 100 wt% of an alkali metal salt and 0 to 60 wt% of an alkaline earth metal salt, based on the total weight of the retarder; preferably, the retarder contains 40-99 wt% of an alkali metal salt and 1-60 wt% of an alkaline earth metal salt, based on the total weight of the retarder;

wherein the alkali metal salt is selected from one or more of sodium carbonate, sodium phosphate and sodium borate; the alkaline earth metal salt is selected from one or more of barium chloride, calcium nitrate and barium borate.

Specifically, when a plurality of alkali metal salts and one or more alkaline earth metal salts are selected, the plurality of alkali metal salts or the plurality of alkaline earth metal salts may be mixed in any mass ratio, which is not limited herein. The mixing ratio employed in the specific embodiment of the present invention is 1: 1.

Furthermore, in order to improve the retardation effect, the strength and the hardness of the retarder, the retarder contains 40-99 wt% of alkali metal salt and 1-60 wt% of alkaline earth metal salt based on the total weight of the retarder.

Further, in order to further prevent the alkali-activated slag-fly ash gelled material from shrinking during the setting process to cause surface cracking, which affects the practical application of the alkali-activated slag-fly ash based gelled material, the retarder contains 40-70 wt% of an alkali metal salt, 5-25 wt% of an alkaline earth metal salt, and 25-35 wt% of a polyalcohol type shrinkage reducing agent and a-or polyether type shrinkage reducing agent, based on the total weight of the retarder. The types of said polyol type shrinkage reducing agents and said polyether type shrinkage reducing agents are well known to those skilled in the art, and are either commercially available or prepared according to methods well known in the art. When the polyol type reducing agent and the polyether type reducing agent are added simultaneously, or when a plurality of polyol type reducing agents or polyether type reducing agents are added simultaneously, the polyol type reducing agent and/or the polyether type reducing agent to be added in a mixed manner may be mixed at an arbitrary mass ratio, and is not limited herein.

In a second aspect, the invention provides an alkali-activated slag-fly ash mortar for preparing an alkali-activated slag-fly ash-based cementitious material, the cementitious material containing, in weight percent, 15% to 30% slag and 70% to 85% fly ash;

in addition, the gel material also contains 3 to 8 percent of alkaline activator, 4 to 8 percent of retarder and 26 to 50 percent of water based on the total weight of the slag and the fly ash;

wherein the retarder is the retarder of the invention.

Preferably, the slag has a particle size of 1-45 μm and the fly ash has a particle size of 1-100 μm to ensure more uniform mixing of the components. More preferably, the slag has a particle size of 15 to 35 μm, and the fly ash has a particle size of 30 to 45 μm.

Specifically, the alkali activator is preferably a mixture of alkali and alkali metal silicate; the base may be an inorganic base conventionally used in the art, such as sodium hydroxide and/or potassium hydroxide, and the alkali metal silicate is preferably sodium silicate and/or potassium silicate. Although the ratio of alkali to alkali metal silicate can be selected within a wide range, it is preferred that the ratio of the alkali to the alkali metal silicate is 1:0.5 to 3 by mass in order to achieve the object of the present invention better. The sodium or potassium silicate had an original modulus of 3.3.

Specifically, the gel material also contains aggregate which accounts for 160-200% of the total weight of the slag and the fly ash. The aggregate may be an aggregate conventionally used in the art, for example, the aggregate includes stones, such as crushed stones, pebbles, and crushed pebbles, and sands, such as river sands, mountain sands, and sea sands. According to an embodiment of the present invention, the aggregate is preferably selected from one or more of river sand, mountain sand, and sea sand.

In a third aspect, the invention also provides an alkali-activated slag-fly ash-based cementing material, which is obtained by curing and maintaining the alkali-activated slag-fly ash mortar.

Specifically, the alkali-activated slag-fly ash mortar is injected into a mold, and is solidified, demoulded and maintained to obtain the alkali-activated slag-fly ash-based cementing material. The solidification, demolding and maintenance are carried out by adopting a conventional technical means, namely, the alkali-activated slag-fly ash mortar is injected into a mold, and demolding is carried out after the alkali-activated slag-fly ash mortar is solidified. The curing conditions comprise that the curing temperature is generally 18-25 ℃, and the curing time is generally 18-36 h; the curing time is generally 25-30 days, in the embodiment of the invention 28 days, and the curing temperature is normal temperature, for example 18-22 ℃.

Preferably, the method for preparing the alkali-activated slag-fly ash mortar comprises:

(1) respectively providing an alkaline excitant aqueous solution and a retarder aqueous solution;

dissolving an alkaline activator in water, sealing and standing for 12-48h to obtain an alkaline activator aqueous solution;

dissolving a retarder in water to obtain a retarder water solution;

(2) and (2) uniformly mixing the alkaline excitant aqueous solution, the retarder aqueous solution, the slag, the fly ash and the selectively added aggregate in the step (1) to obtain the alkaline excitant slag-fly ash mortar.

Specifically, in the step (1), the concentration of the aqueous solution of the alkali-activating agent is not particularly limited, and the amount of water is generally used so as to ensure that the concentration thereof is 20 to 50% by mass. The concentration of the retarder water solution is not particularly limited, and the mass percentage concentration of the retarder water solution is 20-40% guaranteed by the using amount of common water.

In the step (2), the mixing manner of the alkaline activator aqueous solution and the retarder aqueous solution with the slag, the fly ash and the selectively added aggregate is not particularly limited, and the mixing sequence has no particular influence on the performance of the obtained material. Preferably, in order to mix more uniformly, the slag and the fly ash may be mixed uniformly, then the aggregate is selectively added and stirred uniformly to obtain a mixed solid, and then the alkaline activator aqueous solution and the retarder aqueous solution are mixed uniformly with the mixed solid. The mixing mode can adopt mechanical mixing or manual mixing, preferably adopts mechanical mixing, can make the mixed solid obtained after the mixing more even and can reduce the human cost.

According to the preparation method of the alkali-activated slag-fly ash mortar, the dosage of each substance is only required to ensure that the alkali-activated slag-fly ash mortar for preparing the alkali-activated slag-fly ash-based cementing material can be obtained.

The present invention will be described in detail below by way of examples. In the following examples, fluidity was measured by the Cement mortar fluidity test method (GB/T2419-2005); the compressive strength is tested according to the cement mortar strength test method (GB/T17671-1999); the setting time is tested according to the building mortar basic performance test method standard (JGJ/T70-2009); shrinkage was measured according to Cement mortar Dry shrinkage test method (JC/T603-2004). Potassium silicate, sodium silicate, NaOH, KOH, sodium borate, barium chloride, sodium phosphate, barium borate, sodium carbonate and calcium nitrate are all analytical pure medicines purchased from the national medicine group; polyol shrinkage reducing agents were purchased from german minnow; polyether shrinkage reducing agents are purchased from Subot; the slag and fly ash were purchased from a concrete supplier in the local area of salt city, Jiangsu, China.