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CN-122010488-A - Anti-cracking concrete based on response type water slow-release microcapsules and preparation method thereof

CN122010488ACN 122010488 ACN122010488 ACN 122010488ACN-122010488-A

Abstract

The invention provides an anti-cracking concrete based on a response type water slow-release microcapsule and a preparation method thereof, and belongs to the technical field of concrete materials. The concrete comprises cement, aggregate, mineral admixture, water reducer and water slow-release microcapsule. The microcapsule takes hydroxypropyl methyl cellulose and chitosan as slow release carriers, grafts temperature-sensitive monomer N-isopropyl acrylamide and hydrophilic monomer polyethylene glycol monomethyl ether, coats silane coupling agent on the surface, has dual response characteristics of temperature-sensitive and salt-sensitive, and can intelligently release water according to the temperature and ion concentration change in the hydration process. The concrete can effectively regulate and control the hydration process, reduce shrinkage stress, delay crack generation, and has obvious anti-cracking reinforcing effect and good construction applicability.

Inventors

  • WU JIAYI
  • GUO BIYU

Assignees

  • 南通理工学院

Dates

Publication Date
20260512
Application Date
20260119

Claims (10)

  1. 1. The anti-cracking concrete based on the responsive water slow-release microcapsule is characterized by being formed by mixing and pouring cement, aggregate, mineral admixture, water reducer and water slow-release microcapsule; The water slow release microcapsule comprises: (1) The slow release carrier is formed by crosslinking hydroxypropyl methyl cellulose and modified chitosan through glutaraldehyde; (2) The temperature-sensitive monomer is crosslinked on the modified chitosan through polymerization reaction; (3) Hydrophilic monomers are grafted into a chitosan structure through carboxylation reaction, and are introduced into the slow release carrier after being pre-modified; (4) And the silane coupling agent is coated on the surface of the microcapsule.
  2. 2. The anti-cracking concrete based on the responsive water slow-release microcapsules according to claim 1, wherein the aggregate is formed by mixing crushed stone with continuous grading and river sand according to the weight ratio of (3-4): 1.
  3. 3. The anti-cracking concrete based on the responsive water slow-release microcapsules of claim 1, wherein the mineral admixture is metakaolin with an activity index of 110-120% and a particle size of 30-45 um.
  4. 4. The anti-cracking concrete based on the responsive water slow-release microcapsules of claim 1, wherein the water reducer is a polycarboxylic acid high-efficiency water reducer with a solid content of 20-30%, a water reduction rate of 30-40% and a retarding time of 4-8 h.
  5. 5. The anti-cracking concrete based on the responsive water slow release microcapsule according to claim 1, wherein the mass ratio of hydroxypropyl methylcellulose, modified chitosan and glutaraldehyde in the slow release carrier is (1.4-1.6) 1 (0.07-0.13).
  6. 6. The anti-cracking concrete based on the responsive water slow-release microcapsule according to claim 1, wherein the modified chitosan is obtained by reaction polymerization of pre-modified chitosan and a temperature-sensitive monomer, and the mass ratio of the pre-modified chitosan to the temperature-sensitive monomer is 1 (0.2-0.3).
  7. 7. The anti-cracking concrete based on the responsive water slow-release microcapsule according to claim 6, wherein the pre-modified chitosan is prepared by reacting hydrophilic monomers with maleic anhydride and then condensing the hydrophilic monomers with chitosan.
  8. 8. The anti-cracking concrete based on responsive water slow release microcapsules of claim 1, wherein the temperature sensitive monomer is N-isopropyl acrylamide.
  9. 9. The anti-cracking concrete based on responsive water slow release microcapsules of claim 1, wherein the hydrophilic monomer is polyethylene glycol monomethyl ether.
  10. 10. A method for preparing an anti-cracking concrete based on responsive water slow release microcapsules according to any one of claims 1-9, comprising the steps of: (1) Firstly, reacting hydrophilic monomers with maleic anhydride, then reacting with chitosan to obtain pre-modified chitosan, carrying out polymerization reaction on the pre-modified chitosan and temperature-sensitive monomers to obtain modified chitosan, finally adding hydroxypropyl methyl cellulose and glutaraldehyde, drying and granulating the reacted slurry to obtain pre-modified microcapsules, and coating a silane coupling agent to obtain the water slow-release microcapsules; (2) Mixing 100 parts of cement, 300-400 parts of aggregate and 8-15 parts of mineral admixture in parts by weight, stirring for 1-2 min for the first time, adding 42-43 parts of water and 0.7-1.0 part of water reducer, stirring for 2-3 min for the second time, adding 4.5-5.5 parts of water slow-release microcapsule, and stirring for 1-2 min for the third time to obtain the anti-cracking concrete.

Description

Anti-cracking concrete based on response type water slow-release microcapsules and preparation method thereof Technical Field The invention relates to the technical field of concrete, in particular to an anti-cracking concrete based on a responsive water slow-release microcapsule and a preparation method thereof. Background The concrete is used as the most used and core structural material in modern building engineering, the volume stability and long-term durability of the concrete directly determine the safety and service life of a building, and the concrete plays an irreplaceable role in the aspects of guaranteeing the quality of infrastructure and improving the human living environment. The cracking resistance of the concrete member is a key index of durability, and is mainly controlled by the common regulation and control of the internal hydration process, microstructure formation and environmental stress. In order to improve the crack resistance of concrete, various technical routes have been developed in the industry. Among them, the chemical additive modification route is one of the mainstream schemes because of its convenience in engineering application. In particular by adding water reducing agents, expanding agents, mineral admixtures, etc., to reduce water usage, compensate for shrinkage or fill voids, and by using fiber reinforcement techniques (such as CN118878238 a) to bridge and constrain cracks by forming a physical network in the matrix, these methods improve some of the cracking or impervious performance of the concrete to some extent. However, the prior technical schemes still have fundamental limitations when dealing with complex cracking problems of concrete, especially assembly type concrete, (1) the action mechanism is passive and lagged, the technologies of water reducing agent, expanding agent and the like mainly aim at reducing shrinkage sources or afterwards compensating, fiber reinforcement belongs to the core process of cement hydration after crack initiation, all the physical crack resistance after crack initiation is not actively interfered, the internal stress caused by uneven energy release at the initial stage and the later stage of hydration cannot be solved, (2) the concrete hydration is a dynamic exothermic and ion concentration change process, the prior art cannot intelligently respond to the differential requirements of different stages (such as plastic stage, hardening early stage and service stage) on moisture, so that moisture supply and consumption are mismatched in time and space, and (3) the traditional additive is difficult to continuously and effectively play roles in the casting process of concrete because of unsynchronized new and old concrete hydration and large humidity gradient, and the stress concentration and crack initiation in the interface region of the new and old concrete are still high risk regions. Therefore, the technical bottleneck to be broken through in the art is how to develop a regulation technology capable of releasing water according to the needs through the hydration internal state (such as temperature and ion concentration) of the concrete, and coordinate hydration reaction from the source and balance internal stress development, so that full-cycle crack resistance improvement from a plastic stage to a long-term service stage is realized. Disclosure of Invention The invention aims to overcome the defects in the prior art, and provides an anti-cracking concrete based on a response type water slow-release microcapsule and a preparation method thereof, which solve the technical problems of passive hysteresis of a concrete anti-cracking technology and shrinkage cracking caused by water supply and demand mismatch. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: in a first aspect, the invention provides an anti-cracking concrete based on response type water slow-release microcapsules, wherein the anti-cracking concrete is formed by mixing and pouring cement, aggregate, mineral admixture, water reducer and water slow-release microcapsules; The water slow release microcapsule comprises: (1) The slow release carrier is formed by crosslinking hydroxypropyl methyl cellulose and modified chitosan through glutaraldehyde; (2) The temperature-sensitive monomer is crosslinked on the modified chitosan through polymerization reaction; (3) Hydrophilic monomers are grafted into a chitosan structure through carboxylation reaction, and are introduced into the slow release carrier after being pre-modified; (4) And the silane coupling agent is coated on the surface of the microcapsule. Specifically, the aggregate is formed by mixing crushed stone with continuous grading and river sand according to the weight ratio of (3-4): 1. Specifically, the mineral admixture is metakaolin with an activity index of 110-120% and a particle size of 30-45 mu m. Specifically, the water reducer is a polycarboxylic acid