A grout and a method of making the same

Abstract

This invention relates to a grouting material and its preparation method, belonging to the field of building materials technology. The grouting material is a composite mixture of phosphorus-magnesium based cementitious materials, aggregates, steel fibers, functional additives, and water in a mass ratio of 1:0.5–1.5:0.06–0.16:0.03–0.1:0.05–0.15. The grouting material achieves ultra-low water demand, ultra-early strength, ultra-high strength, and good system stability. It exhibits higher compressive strength and deformation resistance than traditional steel fiber grouting materials, and shows no necking under bending or tensile deformation. The grouting material has good elongation, reaching 2%–10%, achieving a compressive strength of over 100 MPa within one day, and a volume shrinkage rate of less than 0.02% after 28 days, making it suitable for rapid emergency repairs in engineering projects.

Description

Technical Field

[0001] This invention relates to a grouting material and its preparation method, belonging to the field of building materials technology. Background Technology

[0002] Traditional grouting materials have slow early strength development, with an initial setting time of 2 to 6 hours and a final setting time of more than 10 hours, which makes it difficult to meet the needs of rapid or quick repair projects.

[0003] Grouting products based on sulfoaluminate series fast-hardening systems have good early mechanical properties, but their reinforcement protection is poor, resulting in low overall mechanical properties. It is difficult to obtain ultra-high strength grouting materials with compressive strength of over 100MPa, and therefore they cannot be used in reinforced concrete projects.

[0004] In the existing technology, silicate-based grouting products have slow early strength development. It often takes 7 to 20 days to reach a compressive strength of 100 MPa. Moreover, silicate-based grouting products have large volume shrinkage, which can only be improved by adding expansion agents. Sometimes, it may even have the negative effect of compressive strength reduction. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, the present invention aims to provide a grouting material and its preparation method, which can effectively solve the problem of slow early strength development of traditional grouting materials, while having better reinforcement protection and mechanical properties.

[0006] To achieve the objectives of this invention, the following technical solutions are provided.

[0007] A grouting material, wherein the grouting material is composed of phosphorus magnesium-based cementitious material, aggregate, steel fiber, functional additives and water in a mass ratio of 1:0.5~1.5:0.06~0.16:0.03~0.1:0.05~0.15 and mixed together.

[0008] The magnesium-phosphorus cementitious material is composed of dead-burned magnesium oxide, ammonium dihydrogen phosphate, borax, fly ash microspheres, and glass powder, wherein the glass powder has a particle size of micro-nano scale; preferably, the magnesium-phosphorus cementitious material is composed of dead-burned magnesium oxide, ammonium dihydrogen phosphate, borax, fly ash microspheres, and glass powder in a mass ratio of 1:0.2-0.4:0.05-0.15:0.05-0.2:0.05-0.2.

[0009] The steel fiber is composed of stainless steel fiber and negative Poisson's ratio fiber; preferably, the steel fiber is composed of stainless steel fiber and negative Poisson's ratio fiber in a mass ratio of 1:1 to 10.

[0010] The negative Poisson's ratio fiber is obtained by shaving and drawing negative Poisson's ratio steel.

[0011] Preferably, the negative Poisson's ratio fiber has a monofilament length of 3mm to 20mm and a diameter of 100μm to 1000μm.

[0012] The functional additive includes a phosphoric acid solution, and may also include one or more of an antifoaming agent and an air-entraining agent; preferably, the functional additive is a phosphoric acid solution with a mass fraction of 10% to 20%.

[0013] The aggregate is an aggregate applicable to grouting materials in the prior art, and the aggregate is required to have a saturated surface dry water absorption rate of less than or equal to 1.5%, a crushing value of less than or equal to 8%, and a fineness modulus of 2.1 to 3.0.

[0014] Preferably, the aggregate contains tailings sand, and the mass fraction of tailings sand is 10% to 20% based on 100% of the total mass of the aggregate; preferably, the particle size of the tailings sand is 0.5 mm to 1 mm, and the density is 3.0 kg / m³. 3 ~3.5kg / m 3 .

[0015] A method for preparing the grouting material according to the present invention, the method comprising the following steps:

[0016] Phosphorus-magnesium based cementitious material, aggregate, functional additives and water are mixed and stirred thoroughly. Then steel fibers are added and stirred thoroughly to prepare a mixture, which is the grouting material of the present invention in a fluid state. The mixture is applied according to the requirements of the grouting material and cured to obtain the solid grouting material of the present invention.

[0017] Beneficial effects

[0018] (1) This invention provides a grouting material, which is composed of phosphorus magnesium-based cementitious material, aggregate, steel fiber, functional additives and water in a mass ratio of 1:0.5~1.5:0.06~0.16:0.03~0.1:0.05~0.15. Based on the above technology, the grouting material achieves ultra-low water demand, ultra-early strength and ultra-high strength, and also has good system stability. It has higher compressive strength and deformation resistance than traditional steel fiber grouting material, and there is no necking phenomenon under bending or tensile deformation. The grouting material has good elongation, which can reach 2%~10%. It can achieve a compressive strength of more than 100MPa in 1 day and a volume shrinkage rate of less than 0.02% in 28 days. It is suitable for rapid emergency repair construction in engineering.

[0019] (2) This invention provides a grouting material, wherein the grouting material uses a magnesium-phosphorus cementitious material composed of dead-burned magnesium oxide, ammonium dihydrogen phosphate, borax, fly ash microspheres, and glass powder; preferably, the magnesium-phosphorus cementitious material is composed of dead-burned magnesium oxide, ammonium dihydrogen phosphate, borax, fly ash microspheres, and glass powder in a mass ratio of 1:0.2-0.4:0.05-0.15:0.05-0.2:0.05-0.2; wherein, the mass ratio of dead-burned magnesium oxide and ammonium dihydrogen phosphate is 1:0.2-0.4, which is conducive to the full formation of struvite, a hydration product. Since this reaction is a chemical reaction, the addition of water... The system reacts quickly to allow sufficient time for construction. By limiting the amount of borax used, the hydration and hardening time can be adjusted to 10-30 minutes. Fly ash microspheres, microscopically resembling glass spheres, are also micron-sized particles with excellent water-reducing properties. When incorporated into the system, they fill the pores of the hardened phosphorus-magnesium-based cementitious material and reduce the water demand, thus improving the system's strength. The glass powder, a micro-nano powder, works in conjunction with the fly ash microspheres to fill the pores of the hardened phosphorus-magnesium-based cementitious material.

[0020] (3) This invention provides a grouting material, wherein the steel fibers used in the grouting material are composites of stainless steel fibers and negative Poisson's ratio fibers; preferably, the steel fibers are composites of stainless steel fibers and negative Poisson's ratio fibers in a mass ratio of 1:1 to 10. Negative Poisson's ratio fibers are fibers made from a new type of steel that have a negative Poisson's ratio effect (significantly reduced Poisson's ratio), no yield plateau, and a strain value greater than 20%. They also have the characteristics of being non-magnetic, high-strength, high-toughness, and highly uniform elongation, and can adapt to large deformations, with a deformation value of 25% to 37%.

[0021] Preferably, the negative Poisson's ratio fiber has a monofilament length of 3mm to 20mm and a diameter of 100μm to 1000μm, which is conducive to the full mixing of the negative Poisson's ratio fiber and the steel fiber, and at the same time can better disperse in the grout slurry.

[0022] (4) The present invention provides a grouting material in which the phosphorus-magnesium-based cementitious material is used in combination with the steel fiber. On the one hand, it can achieve a good anchoring effect between the phosphorus-magnesium-based cementitious material and the steel fiber, and on the other hand, it can also achieve a coating protection effect on the steel fiber system itself, avoiding the steel fiber from rusting and corrosion. The two work together to achieve high early strength and high toughness while having good durability. The grouting material of the present invention has higher compressive strength and deformation resistance than traditional steel fiber grouting materials. At the same time, there is no necking phenomenon under bending or tensile deformation. The elongation of the grouting material can reach 2% to 10%, and the compressive strength after 1 day of construction can reach more than 100 MPa.

[0023] (5) The present invention provides a grouting material, wherein the aggregate in the grouting material is an aggregate applicable to grouting materials in the prior art, and the aggregate is required to have a saturated surface dry water absorption rate of less than or equal to 1.5%, a crushing value of less than or equal to 8%, and a fineness modulus of 2.1 to 3.0. The aggregate has a low water absorption rate and has good hardness and a reasonable fineness range, which is conducive to the strength of the grouting material.

[0024] Preferably, the aggregate contains tailings sand, and the mass fraction of tailings sand is 10% to 20% based on 100% of the total mass of the aggregate; preferably, the particle size of the tailings sand is 0.5 mm to 1 mm, and the density is 3.0 kg / m³. 3 ~3.5kg / m 3 As a fine aggregate, it optimizes the continuous gradation of the entire aggregate, and its spherical particles can achieve a good ball-bearing effect in the grouting material system.

[0025] (6) The present invention provides a grouting material, wherein the functional additive in the grouting material includes a phosphoric acid solution, and may also include one or more of an antifoaming agent and an air-entraining agent; preferably, the functional additive is a phosphoric acid solution with a mass fraction of 10% to 20%; the phosphoric acid solution, as the main component in the functional additive, can achieve an antifreeze effect, so that the grouting material can be used at room temperature or at low temperatures as low as -25°C;

[0026] Preferably, the phosphoric acid solution contains 10% to 20% phosphoric acid by mass; when used in conjunction with the magnesium phosphate-based cementitious material, it can maintain the fluidity of the grout during preparation and use, while also having a good antifreeze effect.

[0027] (7) The present invention provides a method for preparing grouting material. The grouting material described in the present invention can be prepared by the method. The method is simple and easy to implement and can realize large-scale industrial production. Detailed Implementation

[0028] The present invention will be described in detail below with reference to specific embodiments, but this is not intended to limit the scope of the present invention.

[0029] Example 1

[0030] A grouting material, wherein the grouting material is composed of phosphorus magnesium-based cementitious material, aggregate, steel fiber, functional additives and water in a mass ratio of 1:0.5:0.16:0.1:0.05 and mixed together.

[0031] The magnesium-phosphorus cementitious material is composed of calcined magnesium oxide, ammonium dihydrogen phosphate, borax, fly ash microspheres and glass powder in a mass ratio of 1:0.2:0.05:0.05:0.2; the glass powder has a fineness of 2000 mesh.

[0032] The aggregate is composed of tailings sand, rounded sand and sea sand in a mass ratio of 1:2:4;

[0033] The tailings sand has a particle size of 0.5mm to 1mm and a density of 3.0kg / m³. 3 ;

[0034] The saturated surface-dry water absorption rate of the aggregate is 1.2%, the crushing value is 5%, and the fineness modulus is 2.1.

[0035] The steel fiber is composed of stainless steel fiber and negative Poisson's ratio fiber in a mass ratio of 1:1; the stainless steel fiber has a length of 20mm and a diameter of 200μm, and the negative Poisson's ratio fiber is made of negative Poisson's ratio steel through drawing and short cutting, with a single filament length of 3mm and a diameter of 100μm.

[0036] The functional additive is a 20% phosphoric acid solution.

[0037] A method for preparing the grouting material described in this embodiment, comprising the following steps:

[0038] Phosphorus-magnesium based cementitious materials, aggregates, functional additives and water are mixed and stirred thoroughly. Then steel fibers are added and stirred thoroughly to prepare a mixture, which is a grout in a fluid state. The mixture is then applied and cured as required to obtain a solid grout.

[0039] In this embodiment, the water temperature was 0℃ and the experimental environment was -25℃.

[0040] Example 2

[0041] A grouting material, wherein the grouting material is composed of phosphorus magnesium-based cementitious material, aggregate, steel fiber, functional additives and water in a mass ratio of 1:1.5:0.06:0.03:0.15 and mixed together.

[0042] The magnesium-phosphorus cementitious material is composed of calcined magnesium oxide, ammonium dihydrogen phosphate, borax, fly ash microspheres and glass powder in a mass ratio of 1:0.4:0.15:0.2:0.05; the glass powder has a fineness of 2000 mesh.

[0043] The aggregate is composed of tailings sand, sedimentary sand and sea sand in a mass ratio of 1:4:2;

[0044] The tailings sand has a particle size of 0.5mm to 1mm and a density of 3.5kg / m³. 3 ;

[0045] The aggregate has a saturated surface-dry water absorption rate of 1.0%, a crushing value of 8%, and a fineness modulus of 3.0.

[0046] The steel fiber is composed of stainless steel fiber and negative Poisson's ratio fiber in a mass ratio of 1:10; the stainless steel fiber has a length of 13mm and a diameter of 300μm, and the negative Poisson's ratio fiber is made of negative Poisson's ratio steel through drawing and stub cutting, with a single filament length of 20mm and a diameter of 1000μm.

[0047] The functional additive is a 10% phosphoric acid solution.

[0048] A method for preparing the grouting material described in this embodiment, comprising the following steps:

[0049] Phosphorus-magnesium based cementitious materials, aggregates, functional additives and water are mixed and stirred thoroughly. Then steel fibers are added and stirred thoroughly to prepare a mixture, which is a grout in a fluid state. The mixture is then applied and cured as required to obtain a solid grout.

[0050] In this embodiment, the water temperature and experimental environment were both at room temperature (20°C).

[0051] Comparative Example 1

[0052] Based on Example 1, the functional additives were removed, and the remaining steps and conditions were the same as in Example 1.

[0053] Comparative Example 2

[0054] Based on Example 2, the phosphorus-magnesium based cementitious material was replaced with ordinary 42.5 silicate cement (P.O42.5); the grouting material was prepared by mixing ordinary 42.5 silicate cement, aggregate, steel fiber, polycarboxylate superplasticizer and water in a mass ratio of 1:1.5:0.06:0.005:0.23; the remaining steps and conditions were the same as in Example 2.

[0055] Comparative Example 3

[0056] Based on Example 2, the negative Poisson's ratio fiber was removed, and the steel fiber used was the stainless steel fiber with a length of 13 mm and a diameter of 300 μm as in Example 2; the remaining steps and conditions were the same as in Example 2.

[0057] Performance testing experiment

[0058] The performance of the grouting materials prepared in Examples 1 and 2, and Comparative Examples 1 to 3, was tested as follows:

[0059] The compressive and flexural strength were tested according to the test standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)" and the elongation at break was tested according to the standard DBJ61T 112-2021 "Technical Specification for Application of High Ductility Concrete". The test results are shown in Table 1.

[0060] Table 1 Test Results

[0061]

Claims

1. A grouting material, characterized in that: The grouting material is composed of phosphorus-magnesium based cementitious materials, aggregates, steel fibers, functional additives, and water, mixed in a mass ratio of 1:0.5~1.5:0.06~0.16:0.03~0.1:0.05~0.

15. The magnesium phosphate-based cementitious material is composed of calcined magnesium oxide, ammonium dihydrogen phosphate, borax, fly ash microspheres, and glass powder in a mass ratio of 1:0.2~0.4:0.05~0.15:0.05~0.2:0.05~0.2, with the glass powder having a micro-nano particle size. Steel fiber is composed of stainless steel fiber and negative Poisson's ratio fiber in a mass ratio of 1:1~10; negative Poisson's ratio fiber is obtained by cutting and drawing negative Poisson's ratio steel. Functional additives include a phosphoric acid solution with a mass fraction of 10% to 20%; The saturated surface-dry water absorption rate of the aggregate is less than or equal to 1.5%, the crushing value is less than or equal to 8%, and the fineness modulus is 2.1~3.

0.

2. The grouting material according to claim 1, characterized in that: Functional additives also include one or more of defoamers and air-entraining agents.

3. The grouting material according to claim 1, characterized in that: The monofilament length of negative Poisson's ratio fiber is 3mm~20mm, and the diameter is 100μm~1000μm.

4. The grouting material according to claim 1, characterized in that: The aggregate contains tailings sand, and the mass fraction of tailings sand is 10% to 20% based on the total mass of the aggregate (100%).

5. The grouting material according to claim 4, characterized in that: The tailings sand has a particle size of 0.5mm~1mm and a density of 3.0kg / m³. 3 ~3.5kg / m 3 .

6. The grouting material according to claim 3, characterized in that: The aggregate contains tailings sand, and the mass fraction of tailings sand is 10%~20% based on the total mass of the aggregate; the particle size of the tailings sand is 0.5mm~1mm, and the density is 3.0kg / m³. 3 ~3.5kg / m 3 .

7. A method for preparing a grouting material as described in any one of claims 1 to 6, characterized in that: The method steps are as follows: mix the phosphorus magnesium-based cementitious material, aggregate, functional additives and water and stir thoroughly. Then add steel fibers and stir thoroughly to prepare a mixture, which is a grout in a fluid state. Apply the grout according to the requirements of the grout and cure to obtain a solid grout.

Images