A curing agent and use thereof

Abstract

The present application relates to a kind of solidifying agent and its application, belong to building material technical field.The solidifying agent is made of composite active admixture, biomass silicon aluminum admixture and alkaline aluminum activator, and is made into composite according to mass ratio 1:0.1~0.5:0.05~0.15;The application is as the solidifying agent of solidified soil.The solidifying agent is mainly composite active admixture, improves solidified soil strength, biomass silicon aluminum admixture is as fine particle filling, and also helps the strength of solidified soil to increase, alkaline aluminum activator adjusts solidified soil system alkalinity, and plays moderate alkali activation effect;The solidified soil using the solidifying agent shortens solidification time, and early strength is high;Controlled shrinkage effect is good, and there are few cracks, and safety is good.The solidifying agent makes full use of industrial solid waste, biomass solid waste and mine solid waste, and the three synergies, it is a new type of inorganic solid waste-based solidifying agent.

Description

Technical Field

[0001] This invention relates to a curing agent and its application, belonging to the field of building materials technology. Background Technology

[0002] Construction waste accounts for 30% to 40% of total urban waste, with more than half of it being excavated soil. Construction waste has become a major problem hindering urbanization. Fluidized solidified soil is a new type of construction material with certain strength, water stability, low permeability, and long-term stability. It is a system with great inclusiveness and redundancy. The biggest difference between fluidized solidified soil and conventional disposal technologies lies in its lower requirements for the properties of the excavated soil and its significantly improved workability. It has unique technical advantages for filling projects, especially for filling narrow spaces, and can utilize construction waste on-site on a large scale.

[0003] However, the application of fluidized solidified soil currently has two problems: First, the strength development of solidified soil is slow, especially in the early stages when it is safe to walk on, which takes a long time and affects the construction cycle, significantly increasing costs; Second, solidified soil basically does not contain aggregates and is mainly composed of soil and cementitious materials, with extremely high water content, resulting in large volume shrinkage, which in turn leads to many cracks and large settlement, causing certain safety hazards in the filling system. Summary of the Invention

[0004] To address the issues of high carbon emissions from traditional inorganic curing agents that are primarily cement-based, and the large volume shrinkage and long curing time of traditional cured soils, this invention aims to provide a curing agent and its application.

[0005] To achieve the objectives of this invention, the following technical solutions are provided.

[0006] A curing agent, wherein the curing agent is composed of a composite active admixture, a biomass silicon-aluminum admixture and an alkaline aluminum activator in a mass ratio of 1:0.1-0.5:0.05-0.15.

[0007] The composite active admixture is composed of mineral powder and tuff rock powder.

[0008] Preferably, the composite active admixture is composed of mineral powder and tuff powder in a mass ratio of 1:0.1 to 0.5; the mineral powder is S75 grade or higher.

[0009] The biomass silicon-aluminum admixture is composed of rice husk ash, wood powder and bamboo powder in a mass ratio of 1:0 to 0.2:0 to 0.2.

[0010] Preferably, the biomass silicon-aluminum admixture is rice husk ash.

[0011] The rice husk ash refers to the powder and ash collected after calcining rice husks. Specifically, the rice husk ash is the powder and ash collected after calcining rice husks at a temperature of 700°C or higher for 20 to 30 minutes.

[0012] The alkaline aluminum activator is composed of aluminate cement, sulfoaluminate cement, calcium hydroxide and modified bauxite minerals; preferably, the alkaline aluminum activator is composed of aluminate cement, sulfoaluminate cement, calcium hydroxide and modified bauxite minerals in a mass ratio of 1:1~2:0.05~0.2:0.02~0.05.

[0013] The modified bauxite mineral is a type of earthy mineral with alumina as the main component and containing impurities, which is prepared through modification. Specifically, the modified bauxite mineral is prepared by the following method:

[0014] It is prepared by sintering bauxite minerals at 1500℃~1800℃ in the presence of carbon and calcium oxide in a nitrogen or inert gas environment, followed by cooling. The total mass of bauxite minerals, carbon and calcium oxide is 100%, of which the mass fraction of bauxite minerals is 80%~95%, and the balance is carbon and calcium oxide, with a mass ratio of carbon to calcium oxide of 1:0.2~4.

[0015] The preferred modified bauxite mineral is 300-600 mesh powder.

[0016] Sintering is preferably carried out in a nitrogen atmosphere for 2 hours.

[0017] Preferably, the specific surface area of ​​the composite active admixture is 350 m². 2 / kg~800m 2 / kg.

[0018] Preferably, the specific surface area of ​​the biomass silicon-aluminum admixture is 600 m². 2 / kg~2000m 2 / kg.

[0019] Preferably, the specific surface area of ​​the alkaline aluminum activator is 350 m². 2 / kg~600m 2 / kg.

[0020] The preferred modified bauxite mineral has a specific surface area of ​​250 m². 2 / kg~600m 2 / kg.

[0021] An application of the curing agent described in this invention, wherein the application is as a curing agent for solidified soil; the specific application method is as follows:

[0022] The uncured solidified soil can be obtained by mixing the curing agent, clay and water in a mass ratio of 1:5 to 15:3 to 8. The uncured solidified soil can then be poured into a mold.

[0023] When casting, if a high pouring height is required, layered casting can be used. That is, pour 1 to 2 meters of uncured soil to solidify and form the first layer, then pour the second layer on the first layer to solidify and form the second layer, and so on until the casting is completed.

[0024] A type of solidified soil, wherein the solidifying agent used in the solidified soil is the solidifying agent described in this invention; preferably, the solidified soil is composed of solidifying agent, clay and water in a mass ratio of 1:5 to 15:3 to 8, and after compounding and stirring, uncured solidified soil is obtained, which can be solidified soil after pouring and curing.

[0025] Beneficial effects

[0026] (1) This invention provides a curing agent. The main raw materials of the curing agent fully utilize one or more of the following: industrial solid waste tuff rock powder, biomass solid waste rice husk ash, wood powder and bamboo powder, as well as mining solid waste mineral powder. The three work synergistically to make it a new type of inorganic solid waste-based curing agent that is very compatible with the "dual carbon" policy. It is different from the traditional inorganic curing agents that use cement as the main raw material.

[0027] (2) The present invention provides a curing agent, which is composed of composite active admixture, biomass silicon-aluminum admixture and alkaline aluminum activator in a mass ratio of 1:0.1-0.5:0.05-0.15. The composite active admixture is the main component to improve the strength of the solidified soil. The biomass silicon-aluminum admixture serves as a fine particle filler and also helps to increase the strength of the solidified soil. The alkaline aluminum activator adjusts the alkalinity of the solidified soil system and exerts a moderate alkaline activation effect.

[0028] (3) This invention provides a curing agent, which serves as a curing agent for solidified soil. The main components of the curing agent, inorganic composite active admixture and alkaline aluminum activator, can undergo a rapid hydration and hardening reaction. The resulting cementitious material binds the soil particles together to form a whole, thus increasing strength. This can shorten the curing time, result in high early strength, and allow for faster construction. It enables people to walk on the soil within 6 to 12 hours, ensuring continuous backfilling work. This invention solves the problems of slow strength development of solidified soil in the prior art, especially the long waiting time for people to walk on the soil in the early stage, which affects the construction cycle and causes high costs.

[0029] The alkaline conditions provided by the calcium hydroxide and modified bauxite minerals in the alkaline aluminum activator react with water to generate a certain amount of gas, causing the mixture to slightly expand before final setting. At the same time, the rapid hydration and hardening reaction between the composite cementitious components and the alkaline aluminum activator locks in a certain amount of gas, thereby achieving a shrinkage control effect. This solves the technical problem in the existing technology where the solidified soil basically does not contain aggregate, mainly consists of soil and cementitious materials, has extremely high water content, and suffers from large volume shrinkage, which leads to many cracks and large settlement, resulting in certain safety hazards in the filling system.

[0030] Biomass silicon-aluminum admixture is used as filler, taking advantage of its high activity to undergo a hydration and hardening reaction with other raw materials.

[0031] (4) The present invention provides a curing agent, wherein the alkaline aluminum activator is composed of aluminate cement, sulfoaluminate cement, calcium hydroxide and modified bauxite minerals in a mass ratio of 1:1~2:0.05~0.2:0.02~0.05; the early strength of the cured soil is improved by the rapid cementing effect of aluminate cement and sulfoaluminate cement, the alkalinity of the system is adjusted by calcium hydroxide, which is conducive to the activation of admixture activity, and the small amount of modified bauxite minerals allows the system to release appropriate fine bubbles in the early stage of hydration, which counteracts the shrinkage of the cured soil and improves the volume stability of the cured soil.

[0032] (5) The present invention provides a curing agent, wherein the specific surface area of ​​the composite active admixture in the curing agent is 350 m². 2 / kg~800m 2 / kg, the specific surface area of ​​the biomass silicon-aluminum admixture is 600m². 2 / kg~2000m 2 / kg, the specific surface area of ​​the alkaline aluminum activator is 350m². 2 / kg~600m 2 / kg, the specific surface area of ​​the modified bauxite mineral is 250m². 2 / kg~600m 2 / kg, through the combination of coarse and fine particles, a good filling effect and activity activation effect are achieved.

[0033] (6) The present invention provides a curing agent, which is used as a curing agent for solidified soil. The curing agent, clay and water are compounded in a mass ratio of 1:5 to 12:2 to 7, which can ensure the good construction performance of solidified soil and the stable strength of solidified soil.

[0034] (7) The present invention provides a solidified soil, which uses the solidifying agent described in the present invention and has the characteristics of early strength and good volume stability, and also takes into account the characteristics of green and low carbon. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; they are simply some embodiments of the invention.

[0036] Example 1

[0037] A curing agent, wherein the curing agent is composed of a composite active admixture, a biomass silicon-aluminum admixture and an alkaline aluminum activator in a mass ratio of 1:0.1:0.15.

[0038] The composite active admixture is composed of S75 grade mineral powder and tuff rock powder in a mass ratio of 1:0.5.

[0039] The biomass silicon-aluminum admixture is composed of rice husk ash, wood powder and bamboo powder in a mass ratio of 1:0.1:0.1. Among them, the rice husk ash is the powder and ash collected after rice husks are calcined at 750℃ for 20 minutes.

[0040] The alkaline aluminum activator is composed of aluminate cement, sulfoaluminate cement, calcium hydroxide, and modified bauxite minerals in a mass ratio of 1:1:0.05:0.02. The modified bauxite minerals are produced by sintering bauxite minerals as the main material at 1500°C for 2 hours in a nitrogen atmosphere in the presence of carbon and calcium oxide, followed by cooling and grinding into a 600-mesh powder. Based on the total mass of bauxite minerals, carbon, and calcium oxide as 100%, the mass fraction of bauxite minerals is 80%, the mass fraction of carbon is 10%, and the mass fraction of calcium oxide is 10%.

[0041] The specific surface area of ​​the biomass silicon-aluminum admixture is 1500 m². 2 / kg;

[0042] The specific surface area of ​​the composite active admixture is 400 m². 2 / kg;

[0043] The specific surface area of ​​the alkaline aluminum activator is 370 m². 2 / kg;

[0044] The modified bauxite mineral has a specific surface area of ​​260 m². 2 / kg.

[0045] An application of the curing agent described in this embodiment is as a curing agent for solidified soil; the specific application method is as follows:

[0046] The curing agent, clay, and water are mixed in a mass ratio of 1:5:3 to obtain uncured cured soil. The uncured cured soil is then poured in layers to form the first layer. The second layer is then poured on top of the first layer and cured, and so on, until five layers are completed. Each layer can be walked on after curing for 6 hours.

[0047] Example 2

[0048] A curing agent, wherein the curing agent is composed of a composite active admixture, a biomass silicon-aluminum admixture and an alkaline aluminum activator in a mass ratio of 1:0.5:0.05.

[0049] The composite active admixture is composed of S75 grade mineral powder and tuff powder in a mass ratio of 1:0.1.

[0050] The biomass silicon-aluminum admixture is composed of rice husk ash, wood powder and bamboo powder in a mass ratio of 1:0.2:0.2. Among them, the rice husk ash is the powder and ash collected after rice husks are calcined at 800℃ for 30 minutes.

[0051] The alkaline aluminum activator is composed of aluminate cement, sulfoaluminate cement, calcium hydroxide, and modified bauxite minerals in a mass ratio of 1:2:0.05:0.05. The modified bauxite minerals are produced by sintering bauxite minerals as the main material at 1500°C for 2 hours in a nitrogen atmosphere in the presence of carbon and calcium oxide, followed by grinding into a 300-mesh powder. Based on the total mass of bauxite minerals, carbon, and calcium oxide as 100%, the mass fraction of bauxite minerals is 94%, the mass fraction of carbon is 5%, and the mass fraction of calcium oxide is 1%.

[0052] The specific surface area of ​​the biomass silicon-aluminum admixture is 1000 m². 2 / kg;

[0053] The specific surface area of ​​the composite active admixture is 420 m². 2 / kg;

[0054] The specific surface area of ​​the alkaline aluminum activator is 380 m². 2 / kg;

[0055] The specific surface area of ​​the modified bauxite mineral is 286 m². 2 / kg.

[0056] An application of the curing agent described in this embodiment is as a curing agent for solidified soil; the specific application method is as follows:

[0057] The curing agent, clay, and water are mixed in a mass ratio of 1:10:4 to obtain uncured cured soil. The uncured cured soil is then poured in layers to form the first layer. The second layer is then poured on top of the first layer and cured, and so on, until three layers are completed. Each layer can be walked on after curing for 12 hours.

[0058] Example 3

[0059] A curing agent, wherein the curing agent is composed of a composite active admixture, a biomass silicon-aluminum admixture and an alkaline aluminum activator in a mass ratio of 1:0.5:0.1.

[0060] The composite active admixture is composed of S95 grade mineral powder and tuff powder in a mass ratio of 1:0.4.

[0061] The biomass silicon-aluminum admixture is rice husk ash, which is the powder and ash collected after rice husks are calcined at 850℃ for 25 minutes.

[0062] The alkaline aluminum activator is composed of aluminate cement, sulfoaluminate cement, calcium hydroxide, and modified bauxite minerals in a mass ratio of 1:2:0.05:0.03. The modified bauxite minerals are the product of sintering bauxite minerals as the main material at 1700℃ in a nitrogen atmosphere in the presence of carbon and calcium oxide, and then grinding it into a 300-mesh powder. Based on the total mass of bauxite minerals, carbon, and calcium oxide as 100%, the mass fraction of bauxite minerals is 85%, the mass fraction of carbon is 3%, and the mass fraction of calcium oxide is 12%.

[0063] The specific surface area of ​​the biomass silicon-aluminum admixture is 1250 m². 2 / kg;

[0064] The specific surface area of ​​the composite active admixture is 420 m². 2 / kg;

[0065] The specific surface area of ​​the alkaline aluminum activator is 380 m². 2 / kg;

[0066] The specific surface area of ​​the modified bauxite mineral is 286 m². 2 / kg.

[0067] An application of the curing agent described in this embodiment is as a curing agent for solidified soil; the specific application method is as follows:

[0068] The curing agent, clay, and water are mixed in a mass ratio of 1:6:4.5 to obtain uncured cured soil. The uncured cured soil is then poured in layers to form the first layer. The second layer is then poured on top of the first layer and cured, and so on, until all three layers are completed. Each layer can be walked on after curing for 10 hours.

[0069] Comparative Example 1

[0070] The modified bauxite minerals in the alkaline aluminum activator were removed, and the remaining steps and conditions were the same as in Example 1.

[0071] An application of the curing agent described in this embodiment is as a curing agent for solidified soil; the specific application method is as follows:

[0072] The curing agent, clay, and water are mixed in a mass ratio of 1:5:3 to obtain uncured cured soil. This uncured cured soil is then poured in layers to form the first layer. A second layer is poured on top of the first layer and cured, and so on, until five layers are completed. Each layer cures for 8 hours before being walkable. However, the shrinkage is significantly increased compared to Example 1, and the number of cracks in the hardened cured soil is also increased.

[0073] Comparative Example 2

[0074] Ordinary 42.5 silicate cement (PO 42.5), clay, and water are mixed in a mass ratio of 1:10:5 to obtain uncured solidified soil. The uncured solidified soil is then poured in layers to form the first layer. The second layer is then poured on top of the first layer and cured, and so on, until three layers are completed. Each layer can be walked on after curing for 48 hours.

[0075] Comparative Example 3

[0076] Based on Example 3, the alkaline aluminum activator was removed; the remaining steps and conditions were the same as in Example 3.

[0077] Performance testing experiment

[0078] The performance of the solidified soils prepared in Examples 1-3 and Comparative Examples 1-3 was tested as follows:

[0079] The compressive strength test was conducted according to the standard GB / T 17671-2021 Cement Mortar Strength Test Method (ISO Method), and the test results are shown in Table 1 below.

[0080] Table 1 Test Results

[0081]

[0082]

Claims

1. A curing agent, characterized in that: The curing agent is composed of composite active admixture, biomass silicon-aluminum admixture and alkaline aluminum activator in a mass ratio of 1:0.1~0.5:0.05~0.15; The composite active admixture is composed of mineral powder and tuff powder; The biomass silica-alumina admixture is composed of rice husk ash, wood powder and bamboo powder in a mass ratio of 1:0~0.2:0~0.2; the rice husk ash is the powder and ash collected after calcining rice husks; The alkaline aluminum activator is composed of aluminate cement, sulfoaluminate cement, calcium hydroxide, and modified bauxite minerals. Modified bauxite minerals are a type of earthy mineral with alumina as the main component and containing impurities, which is prepared through modification. The composite active admixture is composed of mineral powder and tuff powder in a mass ratio of 1:0.1~0.5, and the mineral powder is grade S75 or higher. The alkaline aluminum activator is composed of aluminate cement, sulfoaluminate cement, calcium hydroxide, and modified bauxite minerals in a mass ratio of 1:1~2:0.05~0.2:0.02~0.

05. The modified bauxite minerals are prepared by the following method: It is prepared by sintering bauxite minerals as the main material in a nitrogen or inert gas environment in the presence of carbon and calcium oxide at 1500°C to 1800°C and then cooling. The total mass of bauxite minerals, carbon and calcium oxide is 100%, the mass fraction of bauxite minerals is 80% to 95%, and the balance is carbon and calcium oxide. The mass ratio between carbon and calcium oxide is 1:0.2 to 4.

2. The curing agent according to claim 1, characterized in that: The modified bauxite mineral is a 300-600 mesh powder; sintering is carried out in a nitrogen atmosphere for 2 hours.

3. The curing agent according to claim 1, characterized in that: The biomass silicon-aluminum admixture is rice husk ash; rice husk ash is the powder and ash collected after rice husks have been calcined at 700℃ for 20 to 30 minutes.

4. The curing agent according to claim 1, characterized in that: The specific surface area of ​​the composite active admixture is 350 m². 2 / kg~800m 2 / kg; The specific surface area of ​​the biomass silicon-aluminum blend is 600 m². 2 / kg ~2000m 2 / kg; The specific surface area of ​​the alkaline aluminum activator is 350 m². 2 / kg~600m 2 / kg; The specific surface area of ​​the modified bauxite mineral is 250 m². 2 / kg~600m 2 / kg.

5. The application of a curing agent as described in any one of claims 1 to 4, characterized in that: As a solidifying agent for soil.

6. The application of the curing agent according to claim 5, characterized in that: The curing agent, clay, and water are mixed in a mass ratio of 1:5~15:3~8 to obtain uncured cured soil, which is then poured into a mold.

7. The application of the curing agent according to claim 6, characterized in that: When casting, a layered casting method is adopted, that is, the uncured solidified soil is poured into a layer of 1 to 2 meters to solidify and form the first layer, and then the second layer is poured on the first layer to solidify and form the second layer, and so on until the casting is completed.

8. A type of solidified soil, characterized in that: The curing agent used in the solidified soil is any one of the curing agents described in 1 to 4.

9. A solidified soil according to claim 8, characterized in that: The solidified soil is composed of a curing agent, clay, and water in a mass ratio of 1:5~15:3~8. After mixing, uncured solidified soil is obtained, and after pouring and curing, solidified soil is obtained.

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