High performance concrete utilizing metakaolin and spent garnet

Abstract

This study deals on the utilization of metakaolin and spent garnet as part of cementitious and fine aggregates replacement in high performance concrete (HPC). HPC offers many benefits especially towards application of structures which sustain higher loads and exposed to harsh environment at the same time such as piers. HPC usually been produced by applying supplementary cementitious material as an admixture to enhance the quality of HPC. Metakaolin is known as one of the common material that has been proven to produce good qualities of HPC. Spent garnet is one of the industrial waste materials which had been recognized as suitable fine aggregates substitution in concrete. Apart from sand mining issue which had been highlighted, excessive amount of spent garnet in the landfill had also seems to jeopardize the environment. Thus, the study on the utilization of spent garnet and metakaolin in producing HPC is performed. Physical properties test of the materials had been conducted and trial mixes had been executed afterwards with replacement of spent garnet in percentage amount of 10%, 20%, 30%, 40%, 50% and 60% by weight. The workability test results showed that at the replacement of 60%, the fresh concrete bled. Compressive strength, flexural strength, splitting tensile strength and modulus of elasticity tests were carried out to determine mechanical properties of the mix proportion. The morphology of the HPC was identified by completing Scanning Electron Microscope (SEM) with Energy Dispersive X-Ray Analysis (EDX) and XRay Diffraction Analysis Test (XRD). The durability test was conducted to observe the resistance of HPCM and HPCMG50 towards chloride penetration and elevated temperature test. HPC with 50% of spent garnet replacement (HPCMG50) indicated the highest value of compressive strength with 92.3 MPa as compared to 65.4 MPa for HPC without any spent garnet replacement (HPCM). As conclusion, this study found that 50% utilization of spent garnet is effective in producing HPC with better mechanical properties and chloride resistance. Hence utilization of 50% of spent garnet as fine aggregates replacement is a good approach in fighting the issue of sand deficit as well as betterment of landfill management.