Effect of age and sulfate chloride environment on the Self-Healing performance of the desert sand engineered cementitious composite materials

Abstract

This study applied pre-damage of 1 % tensile strain and 75 % failure loads to tensile and prismatic specimens of desert sand polyethylene fiber (PE) engineered cementitious composite (ECC) specimens at different ages (3 and 28 days), respectively. Self-healing was applied to the pre-damaged PE-ECC under 5 % Na2SO4 and 3 % NaCl, 5 % Na2SO4, and water environments. The mechanical properties of the PE-ECC after self-healing, the changes in the number and width of cracks, tensile strength and resonance frequency recovery rate were analyzed. Then, the self-healing products and self-healing process of the PE-ECC were further examined by SEM, EDS, and XRD microscopy. Results showed that self-healing PE-ECC could complete the process within 10 days in different environments and found the self-healing process involved the continuous generation and consumption of self-healing products. The 3-day-old self-healing PE-ECC was stronger than its 28-day-old counterpart. The self-healing performance was strongest in 5 % Na2SO4, whereas it was weakest in water. The main self-healing product of the PE-ECC was CaCO3, which was the result of the coupling effect of carbonization, secondary hydration, and erosion product fillings.