Search

CN-121974617-A - Semi-flexible surface layer grouting material and semi-flexible pavement

CN121974617ACN 121974617 ACN121974617 ACN 121974617ACN-121974617-A

Abstract

The invention relates to the field of engineering materials, in particular to a semi-flexible surface layer grouting material and a semi-flexible pavement. The semi-flexible surface layer grouting material comprises, by weight, 100 parts of Portland cement, 4-6 parts of MMA-geopolymer double-core layer microcapsules, 1.5-2.5 parts of basalt fibers, 3-5 parts of nano calcium carbonate, 0.6-1.0 part of polycarboxylic acid water reducer, 0.3-0.5 part of silane coupling agent, 0.2-0.4 part of cement anti-aging agent and 25-28 parts of water. Can provide self-repairing capability of microcracks when applied to semi-flexible pavement.

Inventors

  • CHEN WANHAI
  • LIANG HUI
  • TIAN WANG
  • MA ZIHENG

Assignees

  • 陕西华山路桥集团有限公司

Dates

Publication Date
20260505
Application Date
20251226

Claims (10)

  1. 1. The semi-flexible surface layer grouting material is characterized by comprising the following raw materials in parts by weight: Portland cement 100 parts 4-6 Parts of MMA-geopolymer double-core microcapsule 1.5-2.5 Parts of basalt fiber 3-5 Parts of nano calcium carbonate 0.6-1.0 Part of polycarboxylic acid water reducer Silane coupling agent 0.3-0.5 parts 0.2-0.4 Part of cement anti-aging agent 25-28 Parts of water.
  2. 2. The semi-flexible surface grouting material of claim 1, wherein the MMA-geopolymer dual-core microcapsules are spherical in structure and comprise an outer shell wall, an outer core layer, an inner shell wall and an inner core layer, wherein the outer shell wall is a urea-formaldehyde resin-nano silica composite shell, the outer core layer comprises MMA, the inner shell wall is a urea-formaldehyde resin-nano calcium carbonate composite shell, and the inner core material comprises a geopolymer precursor.
  3. 3. The semi-flexible surface layer grouting material of claim 2, wherein the geopolymer precursor is configured as a metakaolin geopolymer precursor, comprising the following raw materials in parts by weight: Metakaolin 6-7 parts 2-3 Parts of water glass 1-2 Parts of lithium carbonate 2-3 Parts of polyethylene glycol.
  4. 4. A semi-flexible surface layer grouting material according to claim 3, wherein the metakaolin geopolymer precursor further comprises 3-5 parts nano silica sol.
  5. 5. The semi-flexible surface layer grouting material of claim 2, wherein the outer shell wall has a thickness of 2-3 μm.
  6. 6. The semi-flexible surface layer grouting material of claim 2, wherein the thickness of the inner shell wall is 5-8 μm.
  7. 7. The semi-flexible surface layer grouting material according to claim 2, wherein the outer core layer further comprises hydroquinone polymerization inhibitor, and the weight ratio of MMA to hydroquinone polymerization inhibitor is 100 (0.1-0.2).
  8. 8. A process for preparing a semi-flexible surface layer grouting material as claimed in any one of claims 1 to 7, comprising the steps of: A. Preparing MMA-geopolymer double-core microcapsules; B. Mixing basalt fibers with a silane coupling agent, and dispersing for 15min by high-speed stirring (800 r/min) to obtain basalt pretreated fibers; C. Adding a water reducer and 70% of water into silicate cement, stirring at a medium speed (600 r/min) for 4min to form uniform cement slurry, sequentially adding basalt pre-treated fiber, MMA-geopolymer double-core microcapsules, nano calcium carbonate, a cement anti-aging agent and a polycarboxylic acid water reducer into the uniform cement slurry, pouring the rest water, stirring at a high speed (1200 r/min) for 6min, and controlling the fluidity to be 180-200mm to obtain the semi-flexible surface layer grouting material.
  9. 9. The process for preparing a semi-flexible surface layer grouting material according to claim 8, wherein the specific steps of the step a are as follows: preparing an outer core layer, namely mixing MMA with an outer shell wall raw material and water, and reacting for 1-2 hours at 35-40 ℃ by adopting an in-situ polymerization method to form an outer shell wall-outer core layer structure to obtain an outer microcapsule mixed solution; the preparation of the inner layer, namely mixing the geopolymer with the raw material of the shell wall of the inner layer, adopting an in-situ polymerization method to react for 1-2 hours at the temperature of 35-40 ℃, filtering, washing with deionized water, and vacuum drying for 0.5-1 hour at the temperature of 20-60 ℃ to obtain the microcapsule of the inner layer; And forming the composite microcapsule, namely dispersing the inner layer microcapsule in the outer layer microcapsule mixed solution, reacting for 2-3 hours at 40-45 ℃ by adopting an interfacial polymerization method, enabling the outer layer microcapsule to cover the inner layer microcapsule, washing with deionized water after filtering, and drying for 0.5-1 hour at 20-60 ℃ in vacuum to form the MMA-geopolymer double-core microcapsule.
  10. 10. A semi-flexible pavement made of the semi-flexible pavement grouting material according to claims 1-7.

Description

Semi-flexible surface layer grouting material and semi-flexible pavement Technical Field The invention relates to the field of engineering materials, in particular to a semi-flexible surface layer grouting material and a semi-flexible pavement. Background The semi-flexible pavement is a composite pavement formed by pouring cement-based slurry into a large-gap matrix asphalt mixture, has the flexibility of the asphalt pavement and the rigidity of cement concrete, and is widely applied to heavy-duty traffic sections. The semi-flexible surface layer grouting material is a high-fluidity cement-based composite material specially developed for the semi-flexible pavement, and the core is used for filling framework gaps of the large-gap asphalt mixture and is a key functional material for realizing rigid support of the semi-flexible pavement. The semi-flexible surface layer grouting material has the characteristics of high fluidity, good interfacial adhesion with asphalt mixture, excellent durability and the like, and can autonomously permeate into 20-30% of pores of the large-gap asphalt mixture and solidify to form a rigid network structure, so that the semi-flexible pavement is endowed with the core performance of strong bearing and rut resistance. However, the existing semi-flexible surface layer grouting material has obvious technical pain points that micro-crack self-repairing capability cannot be provided for the semi-flexible pavement, so that micro-cracks (0.1-0.3 mm) generated by load impact and temperature stress of the semi-flexible pavement in the service process cannot be repaired autonomously, and the micro-cracks are easily expanded into macroscopic cracks, so that the pavement is peeled off and pits are formed. Disclosure of Invention It is an object of the present disclosure to provide a semi-flexible surface layer grouting material that provides self-healing capability of microcracks when applied to semi-flexible pavement. In order to achieve the above object, the present disclosure provides a semi-flexible surface layer grouting material. The semi-flexible surface layer grouting material comprises, by weight, 100 parts of Portland cement, 4-6 parts of MMA-geopolymer double-core microcapsules, 1.5-2.5 parts of basalt fibers, 3-5 parts of nano calcium carbonate, 0.6-1.0 part of polycarboxylic acid water reducer, 0.3-0.5 part of silane coupling agent, 0.2-0.4 part of cement anti-aging agent and 25-28 parts of water. Through the mode, silicate cement can be subjected to hydration reaction with water to generate products such as hydrated calcium silicate gel, calcium hydroxide and the like to form a three-dimensional network structure, so that basic compression resistance and flexural strength are provided for grouting materials, and the calcium hydroxide generated by hydration maintains the pH value in the slurry within a strong alkaline range of 12-13, so that a reaction environment can be provided for free radical polymerization of MMA and alkali-activated polymerization of geopolymer precursors. When the pavement generates micro cracks of 0.1-0.2mm, the outer shell wall of the microcapsule is broken, MMA is rapidly polymerized into polymethyl methacrylate in a cement alkaline environment to form a flexible sealing layer, the micro cracks are filled, moisture and air permeation are blocked, the cracks are prevented from further expanding, meanwhile, the high toughness of PMMA can buffer dynamic load stress of the pavement, and secondary cracking of a repairing layer is prevented. When the crack is expanded to more than 0.2mm, the inner shell wall is broken, and the geopolymer precursor is subjected to alkali-activated polymerization under the triggering of crack water seepage to form a high-strength aluminosilicate network structure, so that structural reinforcement of the middle crack is realized, the structural reinforcement is matched with the strength of a cement matrix, and the bearing capacity of the repaired pavement is ensured. Basalt fibers are distributed in the slurry in a three-dimensional direction, when the slurry generates micro-cracks, the fibers can form bridging across two ends of the cracks to prevent the cracks from expanding, so that the flexural strength and fracture toughness of the grouting material are improved, and the cracking risk of the slurry caused by temperature stress and load impact is reduced. The nano calcium carbonate has extremely small particle size, can be filled in microscopic holes of cement hydration products, densifies the microscopic structure of slurry, reduces the porosity, improves the compressive strength, the impermeability and the corrosion resistance of grouting materials, and can disperse the internal stress of the slurry as rigid particles to further improve the crack resistance. The polycarboxylic acid water reducer is adsorbed on the surfaces of cement particles to form electrostatic repulsive force, so that the cement particles are dispersed