Research On Self-healing Technology Of Cement-based Composite Microcapsules

Fiber reinforced cementitious composite is a cement-based composite with ultra-high toughness,and its tensile strain capacity can reach more than 3% through a suitable material ratio.Incorporating microcapsules can repair the damaged parts in time when damage occurs inside or outside.The cement-based composite material with fiber will produce detailed cracks when it is damaged,so it will produce better repair effect when the material have microcapsule and fiber at the same time.Because the experiment needs too much manpower,so in this paper,I make the microcapsules with self-healing functions,from the perspective of finite element simulation,analysis the influence of microcapsules on the fiber reinforced cementitious composite,and explore the repair effect of microcapsules.The microcapsules used in this paper are organic microcapsules.the microcapsule's type is globular,as the cyst wall is made of UF resin and the content of it is E-51 epoxy resin.Three types of microcapsules can be produced by controlling the speed of the agitator at 200 rpm,400 rpm,and 600 rpm.In this way we can get the size of microcapsules at 244?m,205?m and 176?m,and respectively measure the encapsulation rate,size distribution and capsule core content of them.Monte Carlo method can provide a random distribution of microcapsules and fiber.In order to establish model,the linear fiber's and microcapsules' random distribution model are accomplished.This essay use the plastic damage model of ABAQUS as matrix's model,crushable foam model as microcapsule's model and a new model include fiber and matrix as fiber's model,defining the interfacial parameters between different materials to verify the workability of the model.The microcapsules made by organic materials have good encapsulation effect and stable shape,so it can be used for the research of self-healing cement-based materials.By comparing the test results with the ABAQUS simulation research results,it is found that with the growth of the amount of microcapsules,the overall compressive strength shows a downward trend,but the downtrend is slower.However,the compressive strength of fiber reinforced cementitious composite with low content of microcapsules increased slightly.Using ABAQUS to establish the four-point bending test model to explore repair effect of the amount of microcapsules on the mechanical properties of matrix.The simulation results prove that with the increase of the amount of microcapsules,the repair effect of the matrix is enhanced,but the repair efficiency is gradually reduced,and the amount of microcapsules has no obvious effect on the generation of cracks.The above research results prove that organic microcapsules have effect on repairing the cracks of cement-based composite materials.When the amount of microcapsules is 3%,the microcapsules have little effect on the mechanical properties and the repair effect is better.