Performance of geopolymer self compacting concrete using spent garnet as sand replacement

Abstract

Robust engineering properties of spent garnet offer a recycling alternative to create efficient construction materials. Recycling of spent garnet provides a costeffective and environmentally responsible solution rather than dumping it as industrial waste. In this context, the present work evaluated the capacity of spent garnet as sand replacement to achieve self-compacting geopolymer concrete. The self-compacting geopolymer concrete was prepared using ground granulated blast furnace slag whereas the river sand was replaced by spent garnet of varying contents in the range of 0 to 100% under constant Liquid/Binder mass ratio of 0.4. Experiments were carried out to evaluate the leaching performance, microstructure, physical and chemical behaviour of the spent garnet specimens. Furthermore, mix design combined with the fresh and hardened features of the spent garnet based self-compacting geopolymer concrete were performed. Performance evaluations of the developed self-compacting geopolymer concrete were made using various tests such as compressive, splitting tensile, flexural, durability and workability (slump, L-box, V-box and T50) consistent with the requirements and guiding principles of European Federation of National Associations representing concrete. Meanwhile, the morphology, bonding and thermal properties of self-compacting geopolymer concrete were determined using X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and thermo gravimetric analysis. Experimental results revealed an enhancement in the workability of the proposed self-compacting geopolymer concrete specimens due to the increase in spent garnet contents. However, the mechanical strength of the proposed self-compacting geopolymer concrete was discerned to be lower compared to the control sample at every garnet content ratio replacement stage. Concretes prepared with sand replaced spent garnet demonstrated excellent resistance to carbonation than the control sample. Based on the analysis, the results suggest that the spent garnet is proven to be a suitable replacement of sand.