Effect of ground granulated blast furnace slag (GGBS) in coconut shell concrete as partial cement replacement

The continual removal of aggregates to produce concrete led to an alarming rate of resource depletion resulting in environmental issues. Meanwhile, the use of cement, the main constituent in concrete production, contributes significantly to global carbon dioxide (C02) emissions during its manufacturing process. This study explores the potential of crushed coconut shells (CS) as an alternative solution to aggregate to produce lightweight aggregate concrete (LWAC) namely coconut shell concrete (CSC). The effect of the utilization of ground granulated blast furnace slag (GGBS) as cement replacement in CSC is also studied. This study aims to determine the mechanical properties, chemical composition, and microscopic examination of CSC with GGBS. Three different samples were cast and tested i.e., normal concrete (NC) as control samples, CSC, and CSC with 10% GGBS. The incorporation of 10% GGBS in CSC as cement replacement improved the compressive strength, splitting tensile strength and flexural strength up to 20.2 N/mm2, 2.2 N/mm2 , and 3.1 N/mm2, respectively. RAMAN spectroscopy test offers important findings in phase detection of cement hydration products at the observed white and dark regions in the concrete samples. The white region denotes possible early strength growth of calcium silicate hydrates (CSH) that contribute to the strength of the concrete samples.