EVALUATING MECHANICAL AND DURABILITY PROPERTIES OF TERTIARY CEMENTITIOUS SYSTEM-BASED CONCRETE

Usage of waste products as cementitious materials in concrete has been a vital concern in the construction sector during the last decades. This study deals with the detailed experimental investigations on the mechanical and durability properties of concrete utilizing Fly Ash (FA) and Silica Fume (SF) as replacements of Ordinary Portland Cement (OPC). Concretes made by varying combinations of OPC, FA, and SF had been tested at 14-and 28-days curing duration including four mixes. The representative mixes were composed of 100% OPC, 25% FA+75% OPC, 10% SF+ 90% OPC and 10% SF+ 20% FA+70% OPC. The laboratory investigations comprised both destructive tests and non-destructive tests. The destructive tests include compressive strength of different concrete mixes. Besides, the non-destructive tests involved the evaluation of concrete properties using Digital Schmidt hammer, ultrasonic pulse velocity (UPV) and rapid chloride permeability test (RCPT). The experimental studies revealed that the replacement of cement content in the combination of 10% SF+ 20% FA + 70 % OPC called a tertiary cementitious system produces a decrease in strength after 14 days with about 15% compared to control mix but 7% increase after 28 days. The output shows the superiority of the replacement of SF in enhancing the concrete durability. Besides, though the inclusion of FA would reduce the concrete compressive strength at early ages, a reduction in the chloride permeability has been observed due to the decrease in the porosity.