Rapid pavement repairing mortar for winter construction, and preparation method and construction process thereof

Abstract

The invention belongs to the technical field of building materials, and particularly relates to quick pavement repairing mortar for winter construction as well as a preparation method and a construction process of the quick pavement repairing mortar. The quick pavement repairing mortar for winter construction, prepared by the invention, is prepared from the following raw materials in parts by weight: 45 to 55 parts of solid waste-based sulphoaluminate cement, 40 to 50 parts of gold tailing sand, 1 to 4 parts of carbide slag, 1 to 3 parts of ettringite seed crystal early strength agent, 0.4 to 1.5 parts of latex powder, 0.2 to 0.4 part of water reducing agent, 0.03 to 0.13 part of water-retaining agent, 0.02 to 0.15 part of defoaming agent and 0.05 to 0.3 part of polypropylene fiber, and the water-solid ratio of the quick pavement repairing mortar is 0.15 to 0.19. Wherein the ettringite seed crystal early strength agent comprises calcium hydroxide, aluminum sulfate octadecahydrate, Fe (OH) 3 and analytically pure phosphoric acid; the mass ratio of the calcium hydroxide to the aluminum sulfate octadecahydrate to the Fe (OH) 3 to the analytically pure phosphoric acid is 1: (1-1.8): (0.2-0.5): (0.16-0.28). According to the overall scheme, the high condensation speed at the low temperature is achieved, and the early strength development is rapid; and the long-term strength is continuously developed without reducing, so that the method has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a rapid road repair mortar for winter construction, its preparation method and construction process. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Thin-layer road repair mortar is typically applied in thicknesses of 3–10 mm. In low-temperature winter environments, conventional repair mortar is prone to freezing due to rapid heat dissipation. The expansion of water crystals leads to a decrease in strength and durability. In existing technologies, ordinary silicate cement or sulfoaluminate cement is commonly used as the cementing material, with the addition of early-strength agents such as sodium sulfate and lithium carbonate, as well as antifreeze agents such as chlorides and nitrites.

[0004] However, ordinary silicate cement has a slow hydration rate, making it difficult to meet the requirements of rapid setting and high early strength of repair mortar at low sub-zero temperatures; conventional sulfoaluminate cement is prone to strength reduction in the later stages, and the material cost is relatively high; in addition, the use of existing early strength agents such as sodium sulfate and lithium carbonate, and antifreeze agents such as chloride salts and nitrites often reduces the later strength and durability of repair mortar, and easily causes phenomena such as salt precipitation and efflorescence in repair mortar; furthermore, additional heat preservation and curing (such as covering with heat insulation blankets or electric blankets) are required after winter construction, which increases the difficulty and cost of construction.

[0005] Therefore, those skilled in the art urgently need to obtain a fast road repair mortar for winter construction to solve problems such as slow setting, low early strength, reduced strength in the later stage, and poor environmental performance in low temperature environments. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a rapid road repair mortar for winter construction, its preparation method, and construction process. The mortar prepared by this invention uses solid waste-based sulfoaluminate cement, gold tailings sand, and carbide slag as the main raw materials, adds a specially formulated ettringite seed crystal early strength agent, and is mixed with 40~60℃ warm water for construction. It has fast low-temperature setting, high early strength (4-hour compressive strength ≥9.9 MPa), and no reduction in later strength (28-day compressive strength ≥65.4 MPa), and does not require additional heat preservation and curing.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a rapid road repair mortar for winter construction, comprising, by weight, 45-55 parts of solid waste-based sulfoaluminate cement, 40-50 parts of gold tailings sand, 1-4 parts of carbide slag, 1-3 parts of ettringite seed crystal early strength agent, 0.4-1.5 parts of latex powder, 0.2-0.4 parts of water-reducing agent, 0.03-0.13 parts of water-retaining agent, 0.02-0.15 parts of defoamer, and 0.05-0.3 parts of polypropylene fiber, wherein the water-solid ratio of the rapid road repair mortar is 0.15-0.19; The calcite seed crystal early strength agent includes calcium hydroxide and aluminum sulfate octadecylhydrate (…). The mixture consists of calcium hydroxide, aluminum sulfate octadecyl hydrate, Fe(OH)3, and analytical grade phosphoric acid; the mass ratio of these components is 1:(1~1.8):(0.2~0.5):(0.10~0.28).

[0008] Preferably, the road surface rapid repair mortar for winter construction comprises, by weight, the following raw materials: 50 parts solid waste-based sulfoaluminate cement, 45 parts gold tailings sand, 2.2 parts carbide slag, 2 parts ettringite seed crystal early strength agent, 0.7 parts latex powder, 0.3 parts water-reducing agent, 0.04 parts water-retaining agent, 0.03 parts defoamer, and 0.15 parts polypropylene fiber; the water-solid ratio of the road surface rapid repair mortar is 0.16. The ettringite seed crystal early strength agent comprises calcium hydroxide, aluminum sulfate octadecyl hydrate, Fe(OH)3, and analytical grade phosphoric acid; the mass ratio of calcium hydroxide, aluminum sulfate octadecyl hydrate, Fe(OH)3, and analytical grade phosphoric acid is 1:1.5:0.3:0.1875, and the purity of the analytical grade phosphoric acid is not less than 85%.

[0009] Preferably, the specific surface area of ​​the solid waste-based sulfoaluminate cement is not less than 350 m². 2 / kg; 1-day flexural and compressive strengths are not less than 6.0 MPa and 35.0 MPa respectively, and 28-day flexural and compressive strengths are not less than 7.5 MPa and 50 MPa respectively.

[0010] Preferably, the particle size of the gold tailings sand is in the range of 0.1~2 mm.

[0011] Preferably, the carbide slag is used after drying and pretreatment, and the calcium hydroxide content is not less than 75% by mass. It is used to adjust the pH value of the mortar and reduce the activation energy of the hydration reaction of solid waste-based sulfoaluminate cement.

[0012] Preferably, the water-reducing agent is a polycarboxylate high-efficiency water-reducing agent with a water reduction rate of not less than 25%. It is used to improve the fluidity of the repair mortar and facilitate construction.

[0013] Preferably, the water-retaining agent is selected from one or more of hydroxypropyl methylcellulose, methylcellulose, and ethylcellulose, and the viscosity of the water-retaining agent is 40,000~100,000 mPa·s. This is used to improve the water retention of mortar and prevent rapid evaporation of moisture due to excessively low relative humidity in winter.

[0014] Preferably, the defoamer is selected from polyether defoamers and silicone defoamers. It is used to remove air bubbles and improve the density and strength of the repair mortar.

[0015] Preferably, the polypropylene fiber has a fiber length of 8-12 mm. This is used to improve the crack resistance of the repair mortar.

[0016] A second aspect of the present invention provides a method for preparing the above-mentioned rapid road repair mortar for winter construction, comprising the following steps: S1. Add calcium hydroxide aqueous solution to a mixed aqueous solution of aluminum sulfate octadecylhydrate and Fe(OH)3, add analytical grade phosphoric acid to the resulting mixed suspension, carry out a water bath reaction, and after post-treatment, obtain ettringite seed crystal early strength agent. S2. Mixed solid waste-based sulfoaluminate cement, gold tailings sand, carbide slag, ettringite seed crystal early strength agent, latex powder, water-reducing agent, water-retaining agent, defoamer, and polypropylene fiber in an aqueous solution to prepare mortar.

[0017] Preferably, in step S1, the ratio of the mixed suspension to analytical grade phosphoric acid is 1 kg:(0.6~2.1) mL.

[0018] Preferably, in step S1, the post-processing includes filtration, drying and grinding, wherein the drying temperature is 40~50℃ and the time is 12~24 h.

[0019] Preferably, in step S2, the aqueous solution is warm water with a temperature controlled at 40~60℃, the stirring time is 2~5 min, and the stirring speed is 60~200 r / min.

[0020] A third aspect of the present invention provides a construction process for a rapid road repair mortar for winter construction, specifically: applying the rapid road repair mortar for winter construction described in the first aspect to the area of ​​the road to be repaired, and then covering and curing the repair material after it has solidified.

[0021] Preferably, the area of ​​the road surface to be repaired is wetted with cool water before applying the mortar, and then the repair mortar is applied within 25 to 35 minutes. The curing time of the film is not less than 2 days.

[0022] A fourth aspect of the present invention provides the application of the rapid road repair mortar described in the first aspect for winter construction in building materials.

[0023] The beneficial effects achieved by one or more technical solutions of the present invention are as follows: (1) The road surface rapid repair mortar prepared by the present invention for winter construction significantly reduces the activation energy of hydration reaction by adding ettringite seed early strength agent and stirring with 40~60℃ warm water, accelerating the transition from the induction period to the acceleration period, and can be demolded in 4 hours to meet the needs of rapid repair; at the same time, ettringite seed promotes the concentration of hydration heat release, and combined with the rapid hydration characteristics of solid waste-based sulfoaluminate cement, the early strength is rapidly improved.

[0024] (2) This invention uses solid waste-based sulfoaluminate cement as the main cementing material, which has a fast hydration rate and concentrated hydration heat release; the addition of carbide slag can further reduce the activation energy of the hydration reaction and stabilize the structure of the hydration products by adjusting the pH value; polypropylene fibers (8~12 mm in length) enhance crack resistance; defoamers (polyether / organosilicon) improve density and prevent salt precipitation and efflorescence; water-retaining agents (hydroxypropyl methylcellulose, etc.) prevent water evaporation in winter and ensure sufficient hydration. The entire technical solution achieves the effect of fast setting speed at low temperature, rapid early strength development, and continuous strength development without shrinkage in the later stage.

[0025] (2) This invention uses solid waste-based cementitious materials, gold tailings sand, carbide slag and other solid waste materials, which are green, low-carbon and low-cost, and provide a high-value utilization path for industrial solid waste. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0027] Figure 1 This is a schematic diagram illustrating the preparation process of the rapid road repair mortar for winter construction provided by the present invention. Detailed Implementation

[0028] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0030] Example 1: This example provides a rapid road repair mortar for winter construction. By weight, the raw material composition of the road surface rapid repair mortar for winter construction includes: 50 parts solid waste-based sulfoaluminate cement, 45 parts gold tailings sand, 2.2 parts carbide slag, 2 parts ettringite seed crystal early strength agent, 0.7 parts latex powder, 0.3 parts polycarboxylate high-efficiency water-reducing agent, 0.04 parts hydroxypropyl methylcellulose water-retaining agent, 0.03 parts polydimethylsiloxane defoamer, and 0.15 parts polypropylene fiber; The ettringite seed crystal early strength agent includes 40 parts calcium hydroxide, 60 parts aluminum sulfate octadecylhydrate, 12 parts Fe(OH)3, and 7.5 parts analytical grade phosphoric acid.

[0031] The specific preparation method of the rapid road repair mortar for winter construction includes the following steps: (1) Place 40 parts of Ca(OH)2 in 2950 parts of deionized water, mix 60 parts of aluminum sulfate octadecylhydrate and 12 parts of Fe(OH)3 in 3750 parts of deionized water, slowly add the Al2(SO4)3-Fe(OH)3 suspension dropwise into the Ca(OH)2 suspension, add 7.5 parts of analytical grade phosphoric acid to the mixed suspension, and then place the mixed solution in a water bath at 35°C and stir for 12 h. After reacting for 12 h, filter the reaction suspension, take the solid, dry and grind it at 40~50°C to obtain ettringite seed crystal early strength agent.

[0032] (2) Mix the components of the repair mortar according to the above-mentioned raw material composition in a mixer to obtain mortar powder. Then, put the mixed repair mortar powder into the mixer, add 16 parts of 50℃ warm water, and stir at a speed of 60~200 r / min for 2.5 min. Pour the obtained repair mortar into a 40×40×160 mm rectangular mold, and immediately place it in a negative temperature curing chamber at -5℃ for curing. After 4 h, demold to obtain the mortar.

[0033] Example 2: This example provides a rapid road repair mortar for winter construction. By weight, the raw material composition of the road surface rapid repair mortar for winter construction includes: 46 parts solid waste-based sulfoaluminate cement, 48 parts gold tailings sand, 3.4 parts carbide slag, 1.4 parts ettringite seed crystal early strength agent, 1.1 parts latex powder, 0.21 parts polycarboxylate high-efficiency water-reducing agent, 0.07 parts methylcellulose water-retaining agent, 0.05 parts polyethylene glycol defoamer, and 0.08 parts polypropylene fiber; The ettringite seed crystal early strength agent includes 29 parts calcium hydroxide, 62 parts aluminum sulfate octadecylhydrate, 10 parts Fe(OH)3, and 5.2 parts analytical grade phosphoric acid.

[0034] The specific preparation method of the rapid road repair mortar for winter construction includes the following steps: (1) Place 29 parts of Ca(OH)2 in 1000 parts of deionized water, mix 62 parts of aluminum sulfate octadecylhydrate and 10 parts of Fe(OH)3 in 4400 parts of deionized water, slowly add the Al2(SO4)3-Fe(OH)3 suspension to the Ca(OH)2 suspension, add 5.2 parts of analytical grade phosphoric acid to the mixed suspension, and then place the mixed solution in a water bath at 30℃ and stir for 12 h. After reacting for 12 h, filter the reaction suspension, take the solid, dry and grind it at 40~50℃ to obtain ettringite seed crystal early strength agent.

[0035] (2) Mix the components of the repair mortar according to the above-mentioned raw material composition in a mixer to obtain mortar powder. Then, put the mixed repair mortar powder into the mixer, add 18.5 parts of 60℃ warm water, and stir at a speed of 60~200 r / min for 2.5 min. Pour the obtained repair mortar into a 40×40×160 mm rectangular mold, and immediately place it in a negative temperature curing chamber at -5℃ for curing. After 4 h, demold to obtain the mortar.

[0036] Example 3: This example provides a rapid road repair mortar for winter construction. By weight, the raw material composition of the road surface rapid repair mortar for winter construction includes: 53 parts solid waste-based sulfoaluminate cement, 42 parts gold tailings sand, 1.5 parts carbide slag, 2.1 parts ettringite seed crystal early strength agent, 1.4 parts latex powder, 0.34 parts polycarboxylate high-efficiency water-reducing agent, 0.11 parts ethyl cellulose water-retaining agent, 0.12 parts polydimethylsiloxane defoamer, and 0.22 parts polypropylene fiber; The ettringite seed crystal early strength agent includes 33 parts calcium hydroxide, 50 parts aluminum sulfate octadecylhydrate, 7 parts Fe(OH)3, and 9.2 parts analytical grade phosphoric acid.

[0037] The specific preparation method of the rapid road repair mortar for winter construction includes the following steps: (1) Place 33 parts of Ca(OH)2 in 2500 parts of deionized water, mix 50 parts of aluminum sulfate octadecylhydrate and 7 parts of Fe(OH)3 in 2900 parts of deionized water, slowly add the Al2(SO4)3-Fe(OH)3 suspension dropwise into the Ca(OH)2 suspension, add 9.2 parts of analytical grade phosphoric acid to the mixed suspension, and then place the mixed solution in a water bath at 40℃ and stir for 12 h. After reacting for 12 h, filter the reaction suspension, take the solid, dry and grind it at 40~50℃ to obtain ettringite seed crystal early strength agent.

[0038] (2) Mix the components of the repair mortar according to the above-mentioned raw material composition in a mixer to obtain mortar powder. Then, put the mixed repair mortar powder into the mixer, add 15.6 parts of 55℃ warm water, and stir at a speed of 60~200 r / min for 2.5 min. Pour the obtained repair mortar into a 40×40×160 mm rectangular mold, and immediately place it in a negative temperature curing chamber at -10℃ for curing. After 4 h, demold to obtain the mortar.

[0039] Comparative Example 1: The components are different from those in Example 1, except that Fe(OH)3 is replaced with Ca(OH)2. The other components, conditions, and preparation methods are completely consistent with those in Example 1.

[0040] Comparative Example 2: Unlike Example 1, no carbide slag was added. The other components, conditions, and preparation methods were completely consistent with Example 1.

[0041] Test Example 1: This test example is a performance test of the rapid road repair mortar prepared for winter construction according to the examples and comparative examples. Specific performance test data are shown in Table 1: Table 1

[0042] As can be seen from the results in Table 1, the performance of the rapid road repair mortars obtained in Examples 1-3 for winter construction is better than that of Comparative Examples 1-2, with Example 1 being the best. Comparative Example 1 failed to demold after 4 hours, making it impossible to test its compressive and flexural strength, indicating that Fe(OH)3 is indispensable in the ettringite seed crystals. Comparative Example 2 did not add carbide slag, and its compressive and flexural strength was lower than that of the mortars prepared in the examples. This shows that without carbide slag, the mortar will set slowly at low temperatures, have insufficient early strength, and decrease in later strength stability, while also increasing the difficulty and cost of construction, and failing to meet the needs of rapid repair in winter.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rapid road repair mortar for winter construction, characterized in that, By weight, its raw material composition includes: 45-55 parts solid waste-based sulfoaluminate cement, 40-50 parts gold tailings sand, 1-4 parts calcium carbide slag, 1-3 parts ettringite seed crystal early strength agent, 0.4-1.5 parts latex powder, 0.2-0.4 parts water-reducing agent, 0.03-0.13 parts water-retaining agent, 0.02-0.15 parts defoamer, and 0.05-0.3 parts polypropylene fiber. The water-solid ratio of the rapid road repair mortar is 0.15-0.

19. The ettringite seed crystal early strength agent comprises calcium hydroxide, aluminum sulfate octadecyl hydrate, Fe(OH)3, and analytical grade phosphoric acid; the mass ratio of calcium hydroxide, aluminum sulfate octadecyl hydrate, Fe(OH)3, and analytical grade phosphoric acid is 1:(1~1.8):(0.2~0.5):(0.16~0.28).

2. The rapid road repair mortar for winter construction as described in claim 1, characterized in that, The road surface rapid repair mortar used for winter construction comprises, by weight, the following raw materials: 50 parts solid waste-based sulfoaluminate cement, 45 parts gold tailings sand, 2.2 parts calcium carbide slag, 2 parts ettringite seed crystal early strength agent, 0.7 parts latex powder, 0.3 parts water-reducing agent, 0.04 parts water-retaining agent, 0.03 parts defoamer, and 0.15 parts polypropylene fiber. The water-solid ratio of the road surface rapid repair mortar is 0.

16. The ettringite seed crystal early strength agent comprises calcium hydroxide, aluminum sulfate octadecyl hydrate, Fe(OH)3, and analytical grade phosphoric acid; the mass ratio of calcium hydroxide, aluminum sulfate octadecyl hydrate, Fe(OH)3, and analytical grade phosphoric acid is 1:1.5:0.3:0.1875, and the purity of the analytical grade phosphoric acid is not less than 85%.

3. The rapid road repair mortar for winter construction as described in claim 1 or 2, characterized in that, The specific surface area of ​​the solid waste-based sulfoaluminate cement is not less than 350 m². 2 / kg; 1-day flexural and compressive strengths are not less than 6.0 MPa and 35.0 MPa respectively, and 28-day flexural and compressive strengths are not less than 7.5 MPa and 50 MPa respectively; Preferably, the particle size of the gold tailings sand is in the range of 0.1~2 mm; Preferably, the carbide slag is used after drying and pretreatment, and the mass content of calcium hydroxide therein is not less than 75%.

4. The rapid road repair mortar for winter construction as described in claim 1 or 2, characterized in that, The water-reducing agent is a polycarboxylate high-efficiency water-reducing agent with a water reduction rate of not less than 25%. Preferably, the water-retaining agent is selected from one or more of hydroxypropyl methylcellulose, methylcellulose, and ethylcellulose, and the viscosity of the water-retaining agent is 40,000 to 100,000 mPa·s; Preferably, the defoamer is selected from polyether defoamers and silicone defoamers; Preferably, the polypropylene fiber has a fiber length of 8-12 mm.

5. A method for preparing a rapid road repair mortar for winter construction as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Add calcium hydroxide aqueous solution to a mixed aqueous solution of aluminum sulfate octadecylhydrate and Fe(OH)3, add analytical grade phosphoric acid to the resulting mixed suspension, carry out a water bath reaction, and after post-treatment, obtain ettringite seed crystal early strength agent. S2. Mixed solid waste-based sulfoaluminate cement, gold tailings sand, carbide slag, ettringite seed crystal early strength agent, latex powder, water-reducing agent, water-retaining agent, defoamer, and polypropylene fiber in an aqueous solution to prepare mortar.

6. The preparation method according to claim 5, characterized in that, In step S1, the ratio of the mixed suspension to analytical grade phosphoric acid is 1 kg:(0.6~2.1) mL; Preferably, the post-processing includes filtration, drying and grinding, wherein the drying temperature is 40~50℃ and the time is 12~24h.

7. The preparation method according to claim 5, characterized in that, In step S2, the aqueous solution is warm water, with the temperature controlled at 40~60℃, and the stirring time is 2~5 min, with a rotation speed of 60~200 r / min.

8. A construction process for a rapid road repair mortar used in winter construction, characterized in that, Specifically, the method involves applying the rapid road repair mortar for winter construction as described in any one of claims 1 to 4 to the area of ​​the road to be repaired, and then covering and curing the area after the repair material has solidified.

9. The construction process as described in claim 9, characterized in that, The road surface area to be repaired is wetted with cool water before applying mortar, and then the repair mortar is applied within 25 to 35 minutes. The curing time for the film covering is no less than 2 days.

10. The application of the rapid road repair mortar for winter construction as described in any one of claims 1 to 4 in building materials.

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