Investigating mechanical properties and self-healing behavior of micro-cracked ECC with different volume of fly ash

摘要

In this paper, the mechanical properties and self-healing behavior of Engineered Cementitious Composite (ECC) are investigated. Three ECC mix proportions with different volume of fly ash are used in this research. The mechanical properties of ECC are revealed via compressive strength, deflection capacity and cracking behavior. Meanwhile, the self-healing behavior of ECCs is investigated by sorptivity test and rapid chloride penetration test (RCPT). Specimens are pre-loaded first to produce micro-cracks, followed by sorptivity and RCPT tests. It is found that both compressive strength and crack width decrease with increasing volume of fly ash, while deflection capacity shows the opposite trend. Micro-cracks produced by pre-loading heal themselves after cured in water, thus decrease sorptivity and charge passed of micro-cracked specimen. Subsequent Environment Scanning Electron Microscope (ESEM) observations also confirm the above findings. The sorptivity test result suggests that ECC mixture with fly ash/cement ratios of 4.0 by weight reveals best self-healing behavior. Therefore, with excellent capacity of crack width control, deformability and self-healing behavior, ECC can be an ideal material for durable concrete infrastructure.