Study On Natural Modified Polymer Microcapsule Self-repairing Cement-based Materials

Under the influence of external force load and environment change,the cementbased materials are easy to appear micro-cracks and local damage.As an important building material,more and more attention has been paid to the study of micro-fracture self-repair of cement-based materials.The aim of this paper is to develop a cement-based material which can repair micro-cracks spontaneously.Through the preparation of microcapsules which can induce the self-repair of cement-based materials,the cement-based materials have the self-repair ability by adding fibers and microcapsules of different dosage into the cement-based materials.The optimal dosage of microcapsule and fiber was obtained by analyzing the influence of admixture amount on mechanical properties and repairing effect of self-repairing cement-based materials.The regression analysis of mechanics and repair data is carried out to obtain a regression model of repair rate of self-repairing cement-based materials.The main conclusions of this study are as follows:1.According to the performance requirements of the microcapsule,the wm-1 natural modified polymer material prepared by the teaching and research department was used as the core material and the calcium alginate gel as the wall material.According to the particle size of the microcapsule,the optimal preparation process was obtained: the concentration of calcium carbonate solution was 1.5%,the concentration of wm-1 solution was 1%,and the concentration of sodium alginate solution was 1%.2.The self-healing cement-based materials were prepared with microcapsules and fibers,and the effects of different wm-1 microcapsules and polypropylene fiber contents on the 28-day strength of cement-based materials were studied.The content of microcapsule and fiber was optimized according to the strength data.When the content of microcapsule is 1.5% and the content of fiber is 0.17%,the mechanical properties of self-repairing cement base are the best and the optimal content is the best.3.The influence of each admixture amount on the repair effect of cement-based materials was judged by the repair rate of material strength and seepage rate.The significance of the effect of fiber and microcapsule on the strength repair rate was analyzed.And when the microcapsule dosage is 0.75%.When the fiber content was 0.17%,the strength repair rate was the highest,and the optimal content was.4.Three repair models of self-repairing cement-based materials were obtained through data fitting and regression analysis.The relationship models of self-repairing cement-based 28-day strength with microcapsule and fiber content were presented.The relationship model of seepage flow and curing time,microcapsule dosage and fiber dosage;The relationship model between the strength recovery rate and the damage load,the content of microcapsule and the content of fiber.The fitting effect of each model is analyzed.