Mechanical response of a vascular self-healing cementitious material system under varying loading conditions

Abstract

The paper presents results from two groups of experimental tests on a pressurised vascular self-healing cementitious material system, in which low viscosity cyanoacrylate was employed as the healing-agent. The first group comprised three series of tests on plain concrete notched prismatic beams. These tests examined the effects on the mechanical response of varying the healing period, the rate of loading and the healing-agent pressure. The second group involved two series of direct tension tests on doubly notched prismatic specimens, each of which had a different crack opening displacement during the healing period. In this second group of tests, healing was allowed to take place in cracks that were held stationary for a period of time, with the degree of mechanical healing being measured for different healing periods. The paper also presents a simplified damage-healing model that is used to interpret the test results and to bring clarity to the indices used to evaluate the degree of healing. The tests were designed to provide new data on simultaneous damage-healing behaviour as well as on the effects of varying pressure, static healing periods and cracking configurations on the mechanical response of this self-healing cementitious material (SHCM) system. These data have been used to guide the development of a new numerical model for SHCMs (reported elsewhere) and should be useful to others who are developing design procedures and/or computational models for similar material systems.