Effects of superabsorbent polymer particleson flexural properties and self-healing behavior of ECC

In order to improve the self-healing behavior and the recovery of mechanical properties of engineered cementitious composites(ECC), the approach of incorporating superabsorbent polymer(SAP)in mixtures is investigated. The rapid water penetration test and four-point bending test were conducted to evaluate the effects of self-healing on the water permeability and mechanical properties of pre-damaged ECC. The self-healing process and self-healing products were observed by the environment scanning electron microscope(ESEM)and energy dispersive X-ray spectroscopy(EDS). The experimental results show that all ECC mixtures exhibit excellent flexural capacity, meanwhile maintaining a crack width below 50 μm. The incorporation of SAP particles in ECC can apparently improve the mechanical recovery of ECC mixtures after 10 healing curing cycles, such as flexural deformation and flexural stiffness. The flexural stiffness of ECC containing 4% SAP particles after self-healing can be recovered to 80%. The self-healing test results show that when the water permeability of ECC mixtures incorporating SAP particles is close to zero, only three healing cycles are needed. When ECC incorporating more SAP particles, the accelerated self-healing process can be finished in the first three cycles, and self-healing product is mixed Ca(OH)2/CaCO3 with CaCO3 being a major component in the later stage. It is, therefore, feasible to produce ECC materials incorporating SAP particles, while simultaneously maintaining higher material ductility and self-healing behavior.