Investigation of different permeability properties of self-healing cementitious composites under colloidal nano silica curing conditions

In this study, the self-healing behavior of engineered cemetitious composites (ECC) containing different types and quantities of fly ash (FA) under colloidal nano silica (CNS) curing conditions was investigated through the examination of their different permeability properties. FA in two different characters, Class F and Class C, were used in the preparation of the mixtures in high volumes (FA/portland cement = 1.2 and 2.2). Self-healing capacities developed under CNS curing conditions were evaluated by changes in different permeability properties such as rapid chloride permeability test (RCPT) and electrical impedance measurement methods. In addition to these, the self-healing effects of the cracked composites were supported by microstructure analysis with the help of SEM-EDX and XRD tests on the sections taken from the crack interface of the sample. The results have showed that the CNS curing condition helps improve the permeability properties of composites by quickly and effectively covering their micro pores and cracks. In addition, the results of the experiment have revealed the effects of the use of different types and quantities of FA on the self-healing behavior of the ECC material. Finally, correlation analysis of ECC samples was applied according to the results obtained from EI and RCPT test methods and it was revealed that there was a negative significant relationship between test methods.