Study of garnet-sand concrete

Abstract

Garnet sand can be used as an abrasive blasting media. During the process, spent garnet sand is generated as a by-product. It is categorized as a solid waste and must be disposed in a proper manner. The purpose of this project is to assess the feasibility of using these garnet sand as a partial replacement over the traditional silica sand in the production of concrete. Three different percentage by weight of spent and recycled garnet sand were casted respectively. Their compressive strength were then compared to the control sample which does not contain any garnet sand. It is observed that in general, garnet sand lowers the compressive strength of concrete. Both spent and garnet sand were examined using sieve test and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX). Both spent and garnet sand were found to be poorly graded. This is different from the silica sand which was found to be uniformly graded. Furthermore, the SEM-EDX suggested that both garnet sands, contain high level of Iron and Aluminum. SEM-EDX was used to analysis the chemical composition of garnet sand concrete and silica sand concrete. It is found that while silica sand concrete contains more calcium at age 7th day, there was no significant difference in chemical element weightage. SEM images allow visual inspection of the different concrete samples and it is observed that in general, garnet sand concrete contained more needle and rod like structures which are believed to be ettringite. Lastly, due to the lack of time and restraints, there are certain results which remains inconclusive. Based on the experience and knowledge that are acquire during this project, the student provides recommendations for further study of garnet sand concrete.