Preparation and investigation of self-healing cementitious composite based on DMTDA - epoxy binary microcapsules system

Cement-based material are prone to cracks. Self-healing concrete appealed to extensive discussion owing to its crack-healing functions without human intervene. In this study, epoxy resin microcapsules and dimethyl thio-toluene diamine microcapsules (DMTDA microcapsules) were prepared successfully based on different mechanisms. Both of the microcapsules were spherical with favorable dispersion and good thermal stability. The effects of microcapsules on the fluidity, compressive strength and open porosity of self-healing cementitious composite were investigated, and the self-healing performance was characterized by microscopic observation of the repairable width of single cracks. It turned out that the fluidity and compressive strength of the self-healing cementitious composite decreased gradually with the increase of the concentration of microcapsules. The open porosity of self-healing cementitious composite hydrated for 28 days decreased by 19.1% when the concentration of microcapsules was 9.0% by weight. Ultimately, the single cracks with width below 40 μm could be repaired completely when self-healing cementitious composite was hydrated for 7 days.