Sorptivity and rapid chloride ion penetration of self-compacting concrete using fly ash and copper slag

Abstract

This paper represents experimental work on the mechanical and durability parameters of self-compacting concrete (SCC) with copper slag (CS) and fly ash (FA). In the first phase of the experiment, certain SCC mixes are prepared with six percentages of FA replacing the cement ranging from 5% to 30%. In the second phase, copper slag replaces fine aggregate at an interval of 20% to 100% by taking the optimum percentage value of FA. The performance of SCC mixes containing FA and copper slag is measured with fresh properties, compressive, split tensile and flexural strengths. SCC durability metrics, such as resistance against chloride and voids in the concrete matrix, is measured with rapid chloride ion penetration test (RCPT) and sorptivity techniques. The microstructure of the SCC is analyzed by using SEM and various phases available in the concrete matrix identified with XRD analysis. It is found that when replacing cement with 20% of FA and replacing fine aggregate with 40% of copper slag in SCC, higher mechanical strengths will be delivered. Resistance of chloride and voids in the concrete matrix reaches the optimum value at 40%; and with the increase of dosage, the quality of SCC will be improved. Therefore, it is recommended that copper slag be used as a sustainable material for replacement of fine aggregate.