Environmental complex response homogeneous expansion type self-repairing microcapsule for concrete, and preparation method thereof

Abstract

The invention provides an environmental complex response homogeneous expansion type self-repairing microcapsule for concrete. The microcapsule comprises a core material and a wall material coating the core material. The core material is prepared from, by weight, 80 to 100 parts of a bentonite repairing agent, 10 to 30 parts of a clay curing agent, 15 to 35 parts of a MgO expanding agent and 2 to 8 parts of an adhesive. The wall material is prepared from, by weight, 0.5 to 1 part of a chloride ion triggering agent and 3 to 8 parts of a capsule wall material, and the capsule wall material is ethyl cellulose or polyvinyl alcohol. An expansive product generated after the self-repairing microcapsule, the curing agent and the repairing agent react has excellent mechanical properties, and effective filling of cracks can be guaranteed. Moreover, the microcapsule takes an inorganic material as the core material, and the generated repair product has good compatibility with a matrix, so that the technical problem that the strength of the concrete is reduced due to low compatibility of an organic repair product and the matrix is solved. In addition, the microcapsule introduces chloride ion response into a triggering mode, so that double response of stress and chloride ion triggering is realized, the damage repair sensitivity is high, and the repair response is fast.

Description

technical field [0001] The invention belongs to the field of materials, and relates to a self-repairing material for concrete, in particular to an environment-responsive homogeneous expansion type self-repairing microcapsule and a preparation method thereof. Background technique [0002] Concrete has the characteristics of low cost, good plasticity and convenient material acquisition, and has become one of the most widely used building materials. Reinforced concrete materials are composed of steel bars and concrete materials; among them, the stronger tensile capacity of steel bars makes up for the weaker tensile properties of concrete itself, thereby increasing the application range of concrete materials. However, concrete often cracks due to temperature or infiltration of corrosive media during its service, thereby shortening its service life. The main reasons for concrete cracking are as follows: (1) shrinkage of concrete. During the hardening process, due to the change ...

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Problems solved by technology

At present, for problems such as cracking of concrete structures, self-healing cement-based composite materials based on microcapsule technology have become a research hotspot; most of the existing microcapsule systems use organic materials as repair agents and curing agents, but this microcapsule system has the following problems: There are two problems: (1) the preparation process is cumbersome, the production cost is high, and it is difficult to realize large-scale production and application; (2) and the particle size is small, only between several microns to tens of microns, and the dispersibility in cement-based materials (3) The compatibility between the organic restoration product and the matrix is ​​not high, which reduces the strength of the concrete; (4) The microcapsules at the tip of the crack are triggered by the rupture of the concentrated stress, and there is no guarantee that all the microcapsules can be repaired. Damaged by cracks, the repair efficiency is low; (5) It cannot respond in time to the invasion of harmful ions, causing harmful ions to diffuse into the interior of the concrete through cracks and corrode the concrete and its internal steel bars

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