Foam stabilizing and carbonation resisting enhancer for full-solid waste foam concrete, and preparation method and application thereof

Abstract

This invention discloses a foam stabilizer and anti-carbonation reinforcing agent for all-solid-waste foamed concrete, its preparation method, and its application. The invention uses ettringite, polycarboxylate superplasticizer, thickener, and water as raw materials. First, nano-ettringite is obtained through wet milling, and then mixed uniformly with the thickener to obtain the foam stabilizer and anti-carbonation reinforcing agent for all-solid-waste foamed concrete. When the foam stabilizer and anti-carbonation reinforcing agent prepared by this invention is added at a dosage of 2.8-8.8%, the foam bleeding rate after 1 hour is ≤10%, the 7-day strength of all-solid-waste foamed concrete is increased by more than 30%, the 28-day strength is increased by more than 20%, and the 28-day anti-carbonation ability is increased by more than 20%.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a foam stabilizer and anti-carbonation reinforcing agent for all-solid-waste foamed concrete, its preparation method, and its application. Background Technology

[0002] With the acceleration of my country's modernization, energy conservation in buildings and the greening of building materials are inevitable trends. Foamed concrete, as a porous cement-based material, is characterized by energy saving, lightweight, and fire resistance, making it a representative of green building materials. However, current foamed concrete production consumes large amounts of cement, resulting in high carbon emissions and low levels of greenness. Furthermore, the poor stability of the slurry during foamed concrete preparation severely impairs its performance. Therefore, using industrial solid waste to partially or completely replace cement in foamed concrete to produce all-solid-waste foamed concrete is of great significance for improving the greenness of foamed concrete.

[0003] Furthermore, the stability of the foam is crucial to the performance of foamed concrete. The vast majority of the porosity in foamed concrete is introduced by the added foam, and precast foam plays a decisive role in improving the porosity of foamed concrete. Generally speaking, the higher the stability and the more uniform the size distribution of the added foam, the better the performance of the foamed concrete. Moreover, foamed concrete has high porosity, with a greater number of interconnected pores compared to ordinary concrete, leading to more severe carbonation and significantly impacting its performance. Therefore, preparing highly stable foam and improving the carbonation resistance of foamed concrete are essential for enhancing its performance. Summary of the Invention

[0004] In view of this, the present invention aims to provide a method for preparing a foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete, so as to solve the problem of poor performance of foamed concrete caused by foam instability during the preparation of existing foamed concrete.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] A method for preparing a foam stabilizer and carbonation-resistant reinforcing agent for all-solid-waste foamed concrete includes the following steps:

[0007] 1) Mix C3A and CaSO4·2H2O in a molar ratio of 1:3 until homogeneous, add a certain amount of deionized water, stir until homogeneous, and react for 5-7 days under nitrogen protection and room temperature to obtain ettringite.

[0008] 2) Add the ettringite, deionized water, and polycarboxylate superplasticizer to a wet mill at a mass ratio of 1:(1.3-1.6):(0.01-0.04), grind at 350-400 rpm under nitrogen protection for 90-120 min, filter the ground material to obtain nano-ettringite slurry;

[0009] 3) Add a thickener to the nano-calcite slurry at a mass ratio of (2-8):(0.4-0.8) and stir until uniform to obtain a foam stabilizer and carbonation inhibitor for all-solid waste foamed concrete.

[0010] Optionally, the grinding media in step 2) is a zirconia grinding media, and the gradation of the zirconia grinding media is 2.4mm:1.4mm:0.8mm = 1:1:2.

[0011] Optionally, the total mass of the grinding media in step 2) is 5-7 times the mass of the ettringite.

[0012] Optionally, the polycarboxylate superplasticizer described in step 2) has a solid content of 39-41% and a water reduction rate of 30-32%.

[0013] Optionally, the median particle size of the nano-calcite in the nano-calcite slurry described in step 2) is 100-250 nm.

[0014] Optionally, the thickener in step 3) is a mixture of styrene and sodium α-alkenyl sulfonate, and the mass ratio of styrene to sodium α-alkenyl sulfonate is (1-4):6.

[0015] The second objective of this invention is to provide a foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete, which is prepared by the above-described method.

[0016] The third objective of this invention is to provide an application of a foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete in all-solid waste foamed concrete. In this application, the cementitious material of the all-solid waste foamed concrete is a ternary cementitious material system composed of slag-phosphogypsum-steel slag, and the dosage of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete is 2.8-8.8% of the mass of the water used to prepare the foam for the all-solid waste foamed concrete.

[0017] Preparation mechanism of the present invention:

[0018] This invention uses ettringite, polycarboxylate superplasticizer, thickener, and water as raw materials. First, nano-ettringite is obtained through wet milling, then mixed uniformly with the thickener to obtain a foam stabilizer and anti-carbonation reinforcing agent for all-solid-waste foamed concrete. The wet-milled nano-ettringite increases the flow resistance of the foam liquid film, thus limiting the discharge of the film liquid. Secondly, it absorbs a large amount of free energy from the liquid film, reducing bubble contraction force. Furthermore, it improves the liquid film strength, inhibiting film rupture and gas diffusion. These factors work together to stabilize the foam. In addition, ettringite, as one of the main hydration products of all-solid-waste foamed concrete (a ternary cementitious material system composed of slag-phosphogypsum-steel slag), becomes a nucleation point due to the nucleation induction effect, promoting the formation of hydration products, improving the density of the foam concrete pore walls, increasing the number of closed pores, and significantly improving the foam concrete's anti-carbonation ability.

[0019] Compared with existing technologies, the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete described in this invention has the following advantages:

[0020] 1. This invention utilizes the principle of stabilizing foam with nanoparticles to produce highly stable foam. Simultaneously, it promotes the formation of ettringite through the nucleation-induced effect of nano-ettringite, resulting in a denser pore structure and improved carbonation resistance. The foam stabilizer and carbonation-resistant enhancer for all-solid-waste foamed concrete prepared by this invention, when added to the foam at a dosage of 2.8-8.8%, exhibits a foam bleeding rate of ≤10% after 1 hour, increases the 7-day strength of foamed concrete by over 30%, increases the 28-day strength by over 20%, and improves the 28-day carbonation resistance by over 20%. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions and effects of the present invention, several embodiments will be provided below. Obviously, the following description is only an embodiment and does not limit the scope of protection of the present invention.

[0022] Example 1

[0023] A method for preparing a foam stabilizer and carbonation-resistant reinforcing agent for all-solid-waste foamed concrete includes the following steps:

[0024] 1) Mix C3A and CaSO4·2H2O at a molar ratio of 1:3 until homogeneous, add a certain amount of deionized water, stir until homogeneous, and react for 5-7 days under nitrogen protection and at room temperature to obtain ettringite. The C3A used is prepared by calcination of analytical grade Ca(OH)2 and Al(OH)3 produced by Sinopharm Group Co., Ltd.; the CaSO4·2H2O used is a commercially available analytical grade product.

[0025] 2) Add the ettringite from step 1) to a wet mill along with deionized water and polycarboxylate superplasticizer at a mass ratio of 1:1.3:0.01. Then, add zirconia grinding media with a mass ratio of 5 times that of ettringite and a gradation of 2.4mm:1.4mm:0.8mm = 1:1:2. Grind at 350 rpm for 90 min under nitrogen protection. Filter the grinding media to obtain a nano-ettringite slurry with a median particle size of 250 nm. The solid content of the polycarboxylate superplasticizer is 39%, and the water reduction rate is 30%.

[0026] 3) Add thickener to the nano-calcite slurry in step 2) at a mass ratio of 2:0.4 and stir until uniform to obtain a foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete. The thickener is a mixture of hyaluronic acid resin and sodium α-alkenyl sulfonate, and the mass ratio of hyaluronic acid resin to sodium α-alkenyl sulfonate is 4:6.

[0027] Example 2

[0028] The difference between this embodiment and embodiment 1 is that in step 3) of this embodiment, the mass ratio of nano-calcite slurry to thickener is 3:0.5, and the mass ratio of warm wheel adhesive to sodium α-olefin sulfonate is 2:6.

[0029] Example 3

[0030] The difference between this embodiment and Embodiment 1 is that the preparation method of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete in this embodiment includes the following steps:

[0031] 1) Mix C3A and CaSO4·2H2O at a molar ratio of 1:3 until homogeneous, add a certain amount of deionized water, stir until homogeneous, and react for 5-7 days under nitrogen protection and at room temperature to obtain ettringite. The C3A used is prepared by calcination of analytical grade Ca(OH)2 and Al(OH)3 produced by Sinopharm Group Co., Ltd.; the CaSO4·2H2O used is a commercially available analytical grade product.

[0032] 2) Add the ettringite from step 1) to a wet mill along with deionized water and polycarboxylate superplasticizer at a mass ratio of 1:1.6:0.02. Then, add zirconia grinding media with a mass ratio of 7 times that of ettringite and a gradation of 2.4mm:1.4mm:0.8mm = 1:1:2. Grind at 365 rpm for 100 min under nitrogen protection. Filter the grinding media to obtain a nano-ettringite slurry with a median particle size of 165 nm. The solid content of the polycarboxylate superplasticizer is 40%, and the water reduction rate is 31%.

[0033] 3) Add thickener to the nano-calcite slurry in step 2) at a mass ratio of 4:0.4 and stir until uniform to obtain a foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete. The thickener is a mixture of hygroscopic rubber and sodium α-alkenyl sulfonate, and the mass ratio of hygroscopic rubber to sodium α-alkenyl sulfonate is 1:6.

[0034] Example 4

[0035] The difference between this embodiment and embodiment 3 is that in step 3) of this embodiment, the mass ratio of nano-calcite slurry to thickener is 5:0.6, and the mass ratio of warm wheel adhesive to sodium α-olefin sulfonate is 3:6.

[0036] Example 5

[0037] The difference between this embodiment and Embodiment 1 is that the preparation method of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete in this embodiment includes the following steps:

[0038] 1) Mix C3A and CaSO4·2H2O at a molar ratio of 1:3 until homogeneous, add a certain amount of deionized water, stir until homogeneous, and react for 5-7 days under nitrogen protection and at room temperature to obtain ettringite. The C3A used is prepared by calcination of analytical grade Ca(OH)2 and Al(OH)3 produced by Sinopharm Group Co., Ltd.; the CaSO4·2H2O used is a commercially available analytical grade product.

[0039] 2) Add the ettringite from step 1) to a wet mill along with deionized water and polycarboxylate superplasticizer at a mass ratio of 1:1.4:0.02. Then, add zirconia grinding media with a mass ratio of 5 times that of ettringite and a gradation of 2.4mm:1.4mm:0.8mm = 1:1:2. Grind at 385 rpm for 110 min under nitrogen protection. Filter the grinding media to obtain a nano-ettringite slurry with a median particle size of 220 nm. The solid content of the polycarboxylate superplasticizer is 40%, and the water reduction rate is 31%.

[0040] 3) Add thickener to the nano-calcite slurry in step 2) at a mass ratio of 6:0.4 and stir until uniform to obtain a foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete. The thickener is a mixture of styrene rubber and sodium α-alkenyl sulfonate, and the mass ratio of styrene rubber to sodium α-alkenyl sulfonate is 2:6.

[0041] Example 6

[0042] The difference between this embodiment and embodiment 5 is that in step 3) of this embodiment, the mass ratio of nano-calcite slurry to thickener is 7:0.7, and the mass ratio of warm wheel adhesive to sodium α-olefin sulfonate is 3:6.

[0043] Example 7

[0044] The difference between this embodiment and Embodiment 1 is that the preparation method of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete in this embodiment includes the following steps:

[0045] 1) Mix C3A and CaSO4·2H2O at a molar ratio of 1:3 until homogeneous, add a certain amount of deionized water, stir until homogeneous, and react for 5-7 days under nitrogen protection and at room temperature to obtain ettringite. The C3A used is prepared by calcination of analytical grade Ca(OH)2 and Al(OH)3 produced by Sinopharm Group Co., Ltd.; the CaSO4·2H2O used is a commercially available analytical grade product.

[0046] 2) Add the ettringite from step 1) to a wet mill along with deionized water and polycarboxylate superplasticizer at a mass ratio of 1:1.6:0.04. Then, add zirconia grinding media with a mass ratio of 6 times that of ettringite and a gradation of 2.4mm:1.4mm:0.8mm = 1:1:2. Grind at 400 rpm for 120 min under nitrogen protection. Filter the grinding media to obtain nano-ettringite slurry with a median particle size of 100 nm. The solid content of the polycarboxylate superplasticizer is 41%, and the water reduction rate is 32%.

[0047] 3) Add thickener to the nano-calcite slurry in step 2) at a mass ratio of 8:0.5 and stir until uniform to obtain a foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete. The thickener is a mixture of hygroscopic rubber and sodium α-alkenyl sulfonate, and the mass ratio of hygroscopic rubber to sodium α-alkenyl sulfonate is 1:6.

[0048] Example 8

[0049] The difference between this embodiment and embodiment 7 is that in step 3) of this embodiment, the mass ratio of nano-calcite slurry to thickener is 4:0.8, and the mass ratio of warm wheel adhesive to sodium α-olefin sulfonate is 2:6.

[0050] The foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete of Examples 1-8 of this invention is used in the preparation of all-solid waste foamed concrete, specifically including the following steps:

[0051] 1) Weigh out the foam stabilizer and anti-carbonation reinforcing agent, animal protein foaming agent and water of the solid waste foam concrete of Examples 1-8 of the present invention according to the proportion of each raw material in Table 1 to obtain a foaming agent solution;

[0052] 2) The foaming agent solution was stirred at high speed to obtain pre-made foam. The test results of the 1-hour water bleeding rate of the obtained pre-made foam are shown in Table 1.

[0053] 3) By weight, 148 parts of phosphogypsum, 385 parts of slag, 59 parts of steel slag, 207.2 parts of water, and 1.8 parts of water-reducing agent are mixed evenly to prepare a solid waste foam concrete paste (a ternary cementitious material system composed of slag-phosphogypsum-steel slag).

[0054] 4) Based on 800 kg / m 3 To achieve the target density, the precast foam from step 2) was added to the all-solid-waste foamed concrete slurry from step 3), molded, demolded, and cured to obtain all-solid-waste foamed concrete. The all-solid-waste foamed concrete was demolded after curing for 24 hours and then cured under standard conditions (20±1℃, RH≥90%). The compressive strength was then determined according to standard JG / T 266–2011 "Foamed Concrete"; the carbonation performance was determined according to standard GB / T 11969-2020 "Test Methods for Autoclaved Aerated Concrete". The test results are shown in Table 2.

[0055] As shown in Table 2, which evaluates the performance of foam and provides data on the compressive strength and carbonation depth of all-solid-waste foamed concrete, when the dosage of foam stabilizer and anti-carbonation reinforcing agent is 2.8-8.8%, the foam bleeding rate after 1 hour is ≤10%. Compared with Example 1 and Comparative Example 1, the compressive strength of foamed concrete after 7 days is increased by 30%, the compressive strength after 28 days is increased by 20%, and the carbonation coefficient is increased by 20%. This indicates that the foam stabilizer and anti-carbonation reinforcing agent for all-solid-waste foamed concrete of this invention not only contributes to the strength development of all-solid-waste foamed concrete, but also improves its anti-carbonation ability.

[0056] Table 1. Foaming agent solution ratio and performance evaluation of pre-made foam

[0057]

[0058] Table 2 Compressive strength and carbonation depth of all-solid-waste foamed concrete

[0059]

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete, characterized in that, Includes the following steps: 1) Mix C3A and CaSO4·2H2O in a molar ratio of 1:3 until homogeneous, add a certain amount of deionized water, stir until homogeneous, and react for 5-7 days under nitrogen protection and room temperature to obtain ettringite. 2) Add the ettringite, deionized water, and polycarboxylate superplasticizer to a wet mill at a mass ratio of 1:(1.3-1.6):(0.01-0.04), grind at 350-400 rpm under nitrogen protection for 90-120 min, filter the ground material to obtain nano-ettringite slurry; 3) Add thickener to the nano-calcium alum slurry at a mass ratio of (2-8):(0.4-0.8) and stir until uniform to obtain a foam stabilizer and carbonation inhibitor for all-solid waste foamed concrete.

2. The preparation method of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete according to claim 1, characterized in that, The total mass of the grinding media in step 2) is 5-7 times the mass of the ettringite.

3. The preparation method of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete according to claim 1, characterized in that, The polycarboxylate superplasticizer mentioned in step 2) has a solid content of 39-41% and a water reduction rate of 30-32%.

4. The preparation method of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete according to claim 1, characterized in that, The median particle size of the nano-calcite in the nano-calcite slurry described in step 2) is 100-250 nm.

5. The preparation method of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete according to claim 1, characterized in that, The thickener mentioned in step 3) is a mixture of styrene and sodium α-alkenyl sulfonate, and the mass ratio of styrene to sodium α-alkenyl sulfonate is (1-4):

6.

6. A foam stabilizer and carbonation-resistant reinforcing agent for all-solid-waste foamed concrete, characterized in that, It is prepared by the method for preparing the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete according to any one of claims 1 to 5.

7. The application of the foam stabilizer and anti-carbonation reinforcing agent for all-solid waste foamed concrete as described in claim 6 in all-solid waste foamed concrete, characterized in that, The cementing material of the all-solid waste foamed concrete is a ternary cementing material system composed of slag-phosphogypsum-steel slag, and the dosage of the foam stabilizer and anti-carbonation reinforcing agent for the all-solid waste foamed concrete is 2.8-8.8% of the mass of the water used to prepare the foam for the all-solid waste foamed concrete.

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