The influence of Ground Granulated Blast Furnace Slag (GGBFS) as Portland Composite Cement (PCC) substitution in improving compressive strength of concrete

Abstract

Concrete is a construction material that is extensively used to build various Infrastructures. The increasing of basic human facilities and the resulting Infrastructures in increasing needs of concrete and cement concrete as the material forming. Many problems in the concrete producing industry are not sustainable. Because of concrete production uses enormous natural resources and the main binding material in concrete is cement. Cement is the result of calcination of lime roomates in the process results in the release of carbon dioxide (CO2). To mitigate this problem and for sustainability concrete, many researches have been done to find a replacement for cement. Geopolymer concrete is an alternative to reduce part of cement. Ground Granulated Blast Furnace Slag (GGBFS) that consist of silica and alumina can be used as a binder to replace part of the Portland Composite Cement (PCC). In this study, concrete compressive strength tests were carried out on 48 specimens of concrete cylinder 15x30 cm. The ratio of substitution GGBFS/PCC used were 0/100, 40/60, 50/50 and 60/40. The specimens were cured at room temperature then tested at the age of 7, 14, 21 and 28 days. The results show that the average compressive strength of concrete at the age of 28 days that GGBFS/PCC ratio of 0/100, 40/60, 50/50 and 60/40 were 26.50, 23.01, 26.65 and 22.56 MPa, respectively. Based on the analysis, 50% substitution of GGBFS can be used to partially replace cement because has the same as normal compressive strength of concrete and can be classified as environmentally friendly or green concrete.