阅读说明：本技术 一种用于炉渣类基层材料的抗冻增强剂及其制备方法 (Anti-freezing reinforcing agent for slag base layer material and preparation method thereof ) 是由 周明凯 李庆宏 胡富平 陈潇 高鹏 郭华 李亮宾 段涛 于 2019-11-19 设计创作，主要内容包括：本发明提供了一种用于炉渣类基层材料的抗冻增强剂及其制备方法,所述抗冻增强剂由以下重量份的原料组成：孔隙充填与应力缓冲组分50-80份、骨架支撑组分5-10份、冰点降低组分5-10份、早强提升组分5-10份；其中,所述骨架支撑组分和所述冰点降低组分负载在所述孔隙充填与应力缓冲组分上。本发明提供的防冻增强剂可以填充在炉渣的孔隙内部,能有效降低了孔内水结冰形成的冻胀应力,并起到缓冲冻胀应力的作用,并在孔隙内部形成相互搭接的晶体骨架,约束孔隙内部水分的冻胀行为,降低了孔隙内水分的冰点,进而达到提高炉渣类半刚性基层材料的抗冻效果,减轻了冻融循环对基层材料的影响。(The invention provides a frost resistance reinforcing agent for a slag base layer material and a preparation method thereof, wherein the frost resistance reinforcing agent is prepared from the following raw materials in parts by weight: 50-80 parts of pore filling and stress buffering component, 5-10 parts of framework supporting component, 5-10 parts of freezing point reducing component and 5-10 parts of early strength improving component; wherein the framework support component and the freezing point depressing component are supported on the pore filling and stress buffering component. The antifreezing enhancer provided by the invention can be filled in the pores of the slag, can effectively reduce the frost heaving stress formed by freezing water in the pores, has the effect of buffering the frost heaving stress, forms mutually overlapped crystal frameworks in the pores, restrains the frost heaving behavior of water in the pores, and reduces the freezing point of the water in the pores, so that the antifreezing effect of the slag semi-rigid base material is improved, and the influence of freeze-thaw cycle on the base material is reduced.)

1. An anti-freezing reinforcing agent for slag base layer materials is characterized by comprising the following raw materials in parts by weight: 50-80 parts of pore filling and stress buffering component, 5-10 parts of framework supporting component, 5-10 parts of freezing point reducing component and 5-10 parts of early strength improving component;

wherein the framework support component and the freezing point depressing component are supported on the pore filling and stress buffering component.

2. The freeze resistance enhancer for slag based substrate materials of claim 1, wherein the pore filling and stress buffering component comprises one or more of polyacrylic resin, chitosan and super absorbent resin.

3. The antifreeze enhancer for slag-based base material according to claim 1, wherein said skeletal support component comprises a gypsum-based expansion factor and a silica-alumina base material, and the mass ratio of said gypsum-based expansion factor to said silica-alumina base material is (1-10): 99.

4. The freeze resistance enhancer for slag-based base materials according to claim 3, wherein the gypsum-based expansion factor comprises one or more of natural dihydrate gypsum, natural hemihydrate gypsum, natural anhydrite, phosphogypsum, desulfurized gypsum and fluorgypsum; the silicon-aluminum base material comprises one or more of fly ash, mineral powder, silica fume, phosphogypsum, rice hull ash and waste incineration fly ash.

5. The freeze resistance enhancer for slag-based substrate materials according to claim 1, wherein the freeze point depressing component comprises one or more of ethylene glycol, glycerin, calcium chloride, magnesium chloride, sodium nitrate, and sodium nitrite.

6. The freeze resistance enhancer for slag-based base material according to claim 1, wherein the early strength enhancing component comprises one or more of triethanolamine, calcium formate, urea, sodium sulfate, lithium carbonate, sodium nitrate, sodium nitrite, and calcium chloride.

7. A method for preparing the antifreeze enhancer for slag-based base materials, which is used for preparing the antifreeze enhancer for slag-based base materials according to any one of claims 1 to 6, comprising the steps of:

uniformly mixing the pore filling with a stress buffering component, a framework supporting component and an ice point depression component to form a base material A, adding a reaction medium into the base material A, continuously stirring to dissolve the base material A into the reaction medium to obtain a mixed solution, and then standing the mixed solution for 22-26 hours;

and heating the mixed solution until the reaction medium in the mixed solution volatilizes to form a base material B, then adding an early strength improving component into the base material B, and uniformly mixing to obtain the antifreeze reinforcing agent for the slag base material.

8. The method for preparing an anti-freeze enhancer for slag-based base material according to claim 7, wherein the mass ratio of the reaction medium to the base material A is (0.5-2): 1.

9. The method of claim 8, wherein the reaction medium comprises one or more of tap water, purified water, and distilled water.

10. The method for preparing an anti-freeze enhancer for slag-based base material according to claim 7, wherein the heating temperature of the mixed solution is 60 ℃ to 120 ℃ during the heating treatment.

Technical Field

The invention relates to the technical field of concrete, in particular to an anti-freezing reinforcing agent for slag base layer materials and a preparation method thereof.

Background

The slag-type base material mainly refers to a semi-rigid base material taking slag as all or part of aggregate, and generally has the characteristics of high porosity, strong water absorption and the like. Since the volume of water is increased by about 9% after becoming ice and an expansion stress of about 2.5MPa is generated, if the water content in the slag pores is excessive, the concrete is damaged to various degrees if the generated expansion stress is greater than the strength internally formed when the concrete is initially set. Therefore, when the slag base material is used in northern cold regions, the problems of poor freezing resistance, severe freeze-thaw damage and the like often occur.

Because the freeze-thaw damage of concrete is mainly caused by the volume change of moisture contained in capillary pores in the cement slurry under the action of temperature, the antifreeze used in the concrete at present mainly comprises inorganic salts, water-soluble organic compounds and composite antifreeze, and the action principle of the antifreeze is based on the hydration process of cement and the regulation and control of products. In the slag base layer material, the freeze-thaw damage mainly lies in the volume expansion of water caused by the temperature reduction after the slag absorbs water; meanwhile, in slag-type base layer materials, the amount of cement and other gelled material slurry is small, and the aim of preventing freezing is difficult to achieve by regulating and controlling the hydration process and products of cement and other gelled materials. Therefore, the antifreeze agent conventionally used in concrete has no significant effect of improving the antifreeze performance of slag-based base layer materials.

Disclosure of Invention

The invention aims to solve the technical problems of poor freezing resistance, easy freeze-thaw damage and the like of slag base layer materials to a certain extent.

In order to solve the problems, the invention provides an anti-freezing reinforcing agent for slag base layer materials, which comprises the following raw materials in parts by weight: 50-80 parts of pore filling and stress buffering component, 5-10 parts of framework supporting component, 5-10 parts of freezing point reducing component and 5-10 parts of early strength improving component; wherein the framework support component and the freezing point depressing component are supported on the pore filling and stress buffering component.

Optionally, the pore filling and stress buffering component comprises one or more of polyacrylic resin, chitosan, and super absorbent resin.

Optionally, the skeleton supporting component comprises a gypsum expansion factor and a silica-alumina base material, and the mass ratio of the gypsum expansion factor to the silica-alumina base material is (1-10): 99.

Optionally, the gypsum-based expansion factor comprises one or more of natural dihydrate gypsum, natural hemihydrate gypsum, natural anhydrite, phosphogypsum, desulphogypsum and fluorgypsum; the silicon-aluminum base material comprises one or more of fly ash, mineral powder, silica fume, phosphogypsum, rice hull ash and waste incineration fly ash.

Optionally, the freezing point depressing component comprises one or more of ethylene glycol, glycerin, calcium chloride, magnesium chloride, sodium nitrate, and sodium nitrite.

Optionally, the early strength enhancing component comprises one or more of triethanolamine, calcium formate, urea, sodium sulfate, lithium carbonate, sodium nitrate, sodium nitrite, and calcium chloride.

The second purpose of the invention is to provide the preparation method of the anti-freezing enhancer for the slag base layer material, so as to solve the technical problems that the existing slag base layer material is poor in anti-freezing performance and easy to freeze-thaw damage and the like.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a method for preparing a freezing resistance enhancing agent for slag-based base material as described above, comprising the steps of:

uniformly mixing the pore filling with a stress buffering component, a framework supporting component and an ice point depression component to form a base material A, adding a reaction medium into the base material A, continuously stirring to dissolve the base material A into the reaction medium to obtain a mixed solution, and then standing the mixed solution for 22-26 hours;

and heating the mixed solution until the reaction medium in the mixed solution volatilizes to form a base material B, then adding an early strength improving component into the base material B, and uniformly mixing to obtain the antifreeze reinforcing agent for the slag base material.

Optionally, the mass ratio of the reaction medium to the binder A is (0.5-2): 1.

Optionally, the reaction medium comprises one or more of tap water, purified water and distilled water.

Optionally, in the heating treatment of the mixed solution, the heating temperature is 60 ℃ to 120 ℃.

Compared with the prior art, the antifreeze reinforcing agent for the slag base layer material and the preparation method thereof provided by the invention have the following advantages:

(1) the antifreeze reinforcing agent provided by the invention is based on the material composition characteristics of a slag base layer and the freeze-thaw damage principle of the slag base layer, and takes a pore filling and stress buffering component, a skeleton supporting component, an ice point reducing component and an early strength improving component as main raw materials; when the anti-freezing reinforcing agent is used, the anti-freezing reinforcing agent can be filled in the pores of the furnace slag, can effectively reduce frost heaving stress formed by freezing water in the pores, has the effect of buffering the frost heaving stress, forms a mutually-lapped crystal framework in the pores, restrains frost heaving behaviors of water in the pores, reduces the freezing point of the water in the pores, further achieves the anti-freezing effect of improving the semi-rigid base material such as the furnace slag, reduces the influence of freeze-thaw cycle on the base material, and further enhances the anti-cracking performance of the base layer.

(2) According to the invention, the skeleton supporting material and the freezing point depression component are loaded on the pore filling and stress buffering component through the reaction medium, so that the pore filling, the stress buffering component, the skeleton supporting component and the freezing point depression component form an integral structure, the better cooperation effect of the pore filling, the stress buffering component, the skeleton supporting component and the freezing point depression component can be ensured during use, and the anti-freezing effect of the slag semi-rigid base layer material is further improved.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

In addition, the terms "comprising," "including," "containing," and "having" are intended to be non-limiting, i.e., that other steps and other ingredients can be added that do not affect the results. Materials, equipment and reagents are commercially available unless otherwise specified.

In northern China, a large amount of coal needs to be combusted during heating in winter, and the generated combustion waste slag occupies land and pollutes the environment, so that the reasonable treatment of the residual solid waste after the coal is combusted is very important. Nowadays, cement stabilized macadam basic unit has advantages such as intensity is high, plate body nature is good, often uses in urban road engineering, consequently uses the slag to replace partial rubble and sand, will greatly reduced engineering cost, solves environmental pollution problem simultaneously. However, because the slag has the characteristics of looseness, porosity and strong water absorption, when the slag is used in cold regions in northern China, the problems of poor freezing resistance, severe freeze-thaw damage and the like are easily caused; the aim of improving the frost resistance of the existing antifreeze used in concrete is achieved mainly by regulating the hydration process of cement and hydration products, and the freeze-thaw damage of slag-like base layer materials is mainly generated by the expansion of water volume after the slag absorbs water and the temperature is reduced. Due to the difference of action principles, the prior antifreeze agent has an unobvious effect of improving the antifreeze performance of slag-type base layer materials.

In order to solve the problems, the invention provides a component of an antifreezing reinforcer for slag semi-rigid base materials and a preparation method thereof. When the antifreezing enhancer is used for the slag semi-rigid base material, the antifreezing enhancer can be filled in the pores of the slag and form a crystal skeleton, so that the volume change of water in the pores is greatly reduced, the frost resistance of the slag semi-rigid base material is effectively improved, and the influence of freeze-thaw cycle on the base material is reduced.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, specific embodiments thereof are described in detail below.

An anti-freezing reinforcing agent for slag base layer materials is composed of the following raw materials in parts by weight: 50-80 parts of pore filling and stress buffering component, 5-10 parts of framework supporting component, 5-10 parts of freezing point reducing component and 5-10 parts of early strength improving component; wherein the skeleton supporting component and the freezing point depressing component are loaded on the pore filling and stress buffering component.

It can be understood that the antifreeze enhancer in the embodiment of the invention is designed and prepared based on the material composition characteristics of the slag-based substrate and the freeze-thaw damage principle thereof, and is mainly used for the slag-based substrate material. The slag-type base material is mainly a semi-rigid base material with slag as a whole or part of aggregate. Wherein the slag mainly comprises gasification slag, coal-to-liquid slag, Circulating Fluidized Bed (CFB) boiler slag or coal-fired boiler slag. The stability types mainly comprise cement stabilization type, cement fly ash stabilization type, lime fly ash stabilization type, cement lime fly ash stabilization type and the like. That is, the slag-based base material may be a lime-stabilized slag-based base layer, a lime fly ash-stabilized slag-based base layer, or the like, which is not specifically listed here, but other aggregates such as crushed stone, gravel, or the like may be added to the base material, and the present invention is not limited thereto.

Specifically, the pore filling and stress buffering component comprises one or more of polyacrylic resin, chitosan and super absorbent resin. The organic super absorbent resin is used as a pore filling and stress buffering material, and when the organic super absorbent resin is used for a slag-type base material, the pore filling and stress buffering material is firstly absorbed by pores of slag, so that the effect of filling the pores of the slag is achieved; meanwhile, the characteristic of high flexibility of the water-absorbent resin is utilized, and the function of buffering frost heaving stress can be achieved during water freezing and thawing. In the embodiment of the invention, the doping amount of the pore filling and stress buffering components accounts for 50-80 wt% of the total components of the anti-freezing reinforcing agent.

The framework support component comprises gypsum expansion factors and a silica-alumina base material. The gypsum expansion factor contains dithio trioxide (SO)₃)，SO₃The calcium sulfate reacts with tricalcium aluminate (C3A) in the cement to generate hydrated calcium sulfoaluminate with low solubility, so that the concentration of C3A in a liquid phase can be reduced, the rapid setting effect is prevented, and the setting process of the cement is delayed; it can be seen that the gypsum expansion factor not only can effectively adjust the cement setting time, but also can improve the early strength to a certain extent. By utilizing the technical principle that a sulfur-series expanding agent and a silicon-aluminum material generate needle-rod-shaped ettringite crystals in an alkaline environment, the needle-rod-shaped ettringite crystals (namely hydrated calcium aluminate C-A-H of a cement hydration product is combined with sulfate ions to generate hydrated calcium sulfoaluminate crystals) are generated in the hydration environment of the framework supporting material meeting water and inorganic binders, so that mutually-overlapped crystal frameworks are formed inside slag pores, and the frost heaving behavior of water inside the pores is effectively restrained. In the embodiment of the invention, the mixing amount of the framework supporting component accounts for 5-10 wt% of the total components of the antifreeze reinforcing agent.

Wherein the gypsum expansion factor comprises one or more of natural dihydrate gypsum, natural hemihydrate gypsum, natural anhydrite, phosphogypsum, desulfurized gypsum and fluorgypsum; the silicon-aluminum base material comprises one or more of fly ash, mineral powder, silica fume, phosphogypsum, rice hull ash and waste incineration fly ash. The gypsum expansion factor and the silicon-aluminum base material are loaded on the pore filling and stress buffering material, the proportion of the gypsum expansion factor and the silicon-aluminum base material can be determined according to actual requirements, and in the embodiment of the invention, the mass ratio of the gypsum expansion factor to the silicon-aluminum base material is (1:99) to (10: 99).

The freezing point depressing component comprises one or more of ethylene glycol, glycerin, calcium chloride, magnesium chloride, sodium nitrate and sodium nitrite. The freezing point depression component is loaded on the pore filling and stress buffering material, and the freezing point depression performance of the freezing point depression component can be utilized to pertinently depress the freezing point of water in the pores of the slag, thereby effectively improving the freezing resistance performance of the slag. In the embodiment of the invention, the dosage of the antifreeze enhancer accounts for 5 to 10 weight percent of the total components of the antifreeze enhancer.

The early strength improving component comprises one or more of triethanolamine, calcium formate, urea, sodium sulfate, lithium carbonate, sodium nitrate, sodium nitrite and calcium chloride, and the mixing amount of the early strength improving component accounts for 5-10 wt% of the total components of the antifreeze reinforcing agent. The early strength improving component can accelerate the hydration of cement, so that the concrete is quickly condensed in a low-temperature environment, and the influence of water freezing on the hydration of the cement is reduced; the strength performance of the inorganic binder slurry is improved, so that the expansion pressure generated by frost heaving of water in the slag is effectively resisted, and the frost resistance of the inorganic binder slurry is improved in an auxiliary manner.

According to the antifreeze reinforcing agent for the slag semi-rigid base material provided by the embodiment of the invention, the framework supporting material and the freezing point depression component are loaded on the pore filling and stress buffering component, so that on one hand, the pore filling and stress buffering component is filled in the slag pores, the water storage space of the pores is reduced, and further, the frost heaving stress formed by water freezing in the pores is effectively reduced; on the other hand, the flexibility of the pore filling and stress buffering component is utilized, so that the effect of buffering frost heaving stress can be achieved during freeze-thaw cycling, and freeze-thaw damage is reduced; in addition, the framework supporting material and the freezing point reducing component enter the inner part of the slag pore along with the pore filling and stress buffering component, so that a mutually overlapped crystal framework can be formed in the pore to restrain the frost heaving behavior of water in the pore and reduce the freezing point of the water in the pore; under the combined action of the early strength agent, the antifreezing effect of the slag semi-rigid base material is further improved, so that the cracking resistance of the base is enhanced.

The invention also provides a preparation method of the antifreeze reinforcing agent for the slag-based base material, which is used for preparing the antifreeze reinforcing agent for the slag-based base material and comprises the following steps:

uniformly mixing the pore filling with the stress buffer component, the framework support component and the freezing point depression component to form a base material A, adding a reaction medium into the base material A, continuously stirring to dissolve the base material A into the reaction medium to obtain a mixed solution, and then standing the mixed solution for 22-26 hours;

and heating the mixed solution, volatilizing a reaction medium in the mixed solution to form a base material B, then adding an early strength improving component into the base material B, and uniformly mixing to obtain the antifreeze reinforcing agent for the slag base material.

Specifically, a reaction medium is added into the base material A, so that the base material A is fully dissolved, the pore filling and stress buffering material in the base material A absorbs water to expand into hydrogel, meanwhile, the framework supporting component and the freezing point depression component enter the pore filling and stress buffering material, after standing for a period of time, the temperature is raised to remove the reaction medium, the framework supporting component and the freezing point depression component can be fully loaded on the pore filling and stress buffering component, the pore filling, the stress buffering component, the framework supporting component and the freezing point depression component form an integral structure, better matching effect of the three components in use is guaranteed, and the anti-freezing effect is further improved.

It is understood that the reaction medium includes one or more of tap water, purified water and distilled water. The proportion of the reaction medium to the base material A can be determined according to actual requirements and the components of the base material A, and in the embodiment of the invention, the mass ratio of the reaction medium to the base material A is (0.5-2): 1.

In addition, in order to ensure that the reaction medium can be completely volatilized, the heating temperature is 60-120 ℃, and the heating time is 360-600 min.

Table 1 shows the freeze-thaw resistance of the same cement stabilized slag pavement material with and without the addition of the above-prepared freeze resistance enhancer.

TABLE 1 influence of the anti-freeze reinforcer on the strength and anti-freeze property of the slag pavement base course

Mix type	Unfrozen strength (MPa)	Freezing and thawing Strength (MPa)	BDR(％)
				Without adding reinforced antifreezing agent	3.8	3.0	78.9
Enhanced anti-freezing agent	4.6	4.4	95.7

Wherein: BDR is the ratio of the compressive strength after freeze-thaw cycles to the compressive strength without freeze-thaw cycles, and the larger the value is, the better the anti-freezing performance is.

With reference to table 1, a frost resistance enhancer is added to a cement stabilized slag pavement material, the compressive strength of a test piece with and without the addition of the frost resistance enhancer before freezing and thawing and the compressive strength of the test piece without the addition of the frost resistance enhancer after freezing and thawing are measured according to the test specification of the freeze-thaw test of T0858-2009 (JTJ E51-2009 inorganic binder stabilized material test specification) and the frost resistance coefficient BDR is calculated, wherein the test shows that: after the enhanced antifreeze agent is added, the compressive strength of the test piece is improved by 21 percent, and the antifreeze coefficient is improved from 78.9 percent to 95.7 percent.

The preparation method of the antifreeze reinforcing agent for slag-based base material is further illustrated below with reference to specific examples. It should be understood that the examples below of the present invention, wherein the pore-filling and stress-buffering component is a super absorbent resin, the framework-supporting component is natural dihydrate gypsum and fly ash, the freezing point-lowering component is ethylene glycol, the early strength-enhancing component is triethanolamine, and the reaction medium is purified water, are provided for illustration purposes only and are not intended to limit the scope of the present invention. The following examples are examples of experimental procedures not specified under specific conditions, generally according to the conditions recommended by the manufacturer. Unless otherwise indicated, percentages and parts are by weight.