Exploring the Effect of a Cement-Based Self-Healing Additive (CS) on the Durability of Cementitious Materials

In order to improve the damage resistance of concrete, a cement-based self-healing additive (abbreviate as CS) was prepared. To investigate the influence of CS on the self-healing performance of cementitious material, X-ray diffraction (XRD) and thermal analysis were used to investigate the effects of different dosages of CS on the hydration process and hydration products of cementitious material. Compressive strength test and load damage self-healing test were used to show the influence of different amounts of CS on the mechanical properties of concrete.  The pore structure distribution of cement paste with different dosages of CS was analyzed using mercury intrusion testing method. The results indicated that different dosages of CS had no effect on the types of hydration products of cementitious material. Adding an appropriate amount of CS can effectively improve the micro pore structure of cement-based materials, reduce the proportion of harmful pores in the structure, and decrease the most probable pore diameter. When microcracks are generated in the structure under load, CS can promote the formation of hydration products inside the structure to fill the microcracks, thereby improving the self-healing performance of cement-based materials. This study provides an idea for improving microcracks and enhancing durability of marine concrete structures.