Sensitivity of embedded channel for self-healing agent delivery on splitting tensile strength of concrete

In self-healing concrete, one of the approaches to deliver healing agents to crack locations is by implementing vascularized channels. However, it is crucial to ensure that these channels do not significantly decrease the mechanical strength of the concrete structure. In this paper, the impact of channel size on the tensile strength of the cementitious material was investigated, both experimentally and numerically. The experiments utilized the Brazilian test, also known as the splitting tensile test, to determine the tensile strength of the material. For numerical simulations, Finite Element Analysis with the phase-field method was employed to simulate the mechanical response and crack propagation of the cementitious material under splitting tensile test. It was found that by bringing the consideration of aggregate distribution, voids ratio, and interfacial transition zone to the numerical model, the prediction accuracy of the model increases significantly when compared with experiments ( i.e., R 2 value of 0.96). Additionally, both experimental and numerical results observed negligible ( i.e., less than 10%) splitting tensile strength reduction when the diameter of (micro) drilling channels are much smaller than the maximum aggregate size of the material. These findings are crucial not only for the design of vascularized self-healing concrete but also for the building and construction of concrete structure in general. • Channel-embedded cementitious cylinders were examined under splitting tensile tests. • Experiments followed ASTM C496, and fractures were simulated using phase-field methods. • The effects of cushion geometry, loading angle, and channel size were evaluated. • Simulations of varying complexity were validated against experimental results. • Channels smaller than the maximum aggregate size reduced flaw sensitivity in the material.