No abstract

No abstract

Millions of tons of spent garnet, a by-product of surface treatment operations, are disposed of in landfills, oceans, rivers, and quarries, among others every year, thus it causes environmental problems. The main objective of this study is to evaluate spent garnet as a sand replacement in concrete prepared with ground granulated blast furnace slag (GGBS)-based self-compacting geopolymer concrete (SCGC). Concrete mixtures containing 0%, 25%, 50%, 75% and 100% spent garnet as a replacement for river sand were prepared with a constant Liquid/Binder (L/B) mass ratio equal to 0.4. Compressive, flexural and splitting tensile strengths as well as workability tests (slump, L-box, U-box and T50) were conducted on concrete containing spent garnet. As per specification and guidelines for self-compacting concrete (EFNARC) standard, the test results showed that the concrete’s workability increased with the increase of spent garnet, while all the other strength values were consistently lower than conventional concrete (SCGC) at all stages of replacement. The results recommended that spent garnet should be used in concrete as a sand replacement up to 25% to reduce environmental problems, costs and the depletion of natural resources.

Garnets are a waste spin-off of surface treatment operations and thus remain a major environmental concern worldwide. The robust engineering properties of these waste garnets offer the opportunity to obtain efficient construction materials by way of their appropriate recycling. In this spirit, the authors evaluate the capacity of spent garnets as sand replacement for achieving self-compacting geopolymer concrete (SCGPC). Such SCGPC specimens are prepared using ground granulated blast-furnace slag (GGBFS) wherein the river sand is replaced by spent garnet at varying contents (0 to 100%) under constant liquid/binder (L/B) mass ratio of 0·4. Performance evaluations of the developed SCGPC samples are made using several tests, including durability, workability and flexural, compressive and splitting tensile strength conforming to the Efnarc standard. Test results reveal an enhancement in the workability of the proposed SCGPC specimen with the increase of spent garnet contents. Furthermore, other strengths are discerned to be lower compared to the control sample at all stages of replacement. It is established that the spent garnet is a prospective candidate for sand replacement up to 25% in terms of environmental friendliness, cost effectiveness and conservation of natural resources.

This paper represents the effects of using waste generated from palm oil industries like ash, shell and fibre on the engineering properties of mortar. Palm Oil Fuel Ash (POFA) was used as cement replacement up to 60% and Oil Palm Kernel Shell (OPKS) as sand replacement in mortar mixture. The Oil Palm Fibre was added to increase the strengthening performance of mortar. The method used to find the water binder ratio was by trial and error method with 1:3 ratio of cement to sand. The cubes size of 70mm x 70mm x 70mm, beams size of 40mm x 40mm x 160mm, and cylinders size of 70mm diameter and 150mm height, were cast and tested for compressive strength, flexural strength and splitting tensile strengths of mortar. Samples were cured in water before testing it at 7, 28, and 60 days. Also, the water absorption of mortar was tested at the age of 28 days. The results showed that oil palm fibre provided more advantages and increase the strength properties especially in the flexural and tensile strength. The addition of Oil Palm Kernel Shell reduced the density of mortar and it can be used for lightweight application.  The test results also showed that as the POFA ratio increased, the compressive strength of mortar decreased. However, as OPKS ratio increased, the density was found to be decreased. The mix proportions using 60% POFA and 20% OPKS was considered as the optimum mix design. The mortar showed optimum strength at 9% with the addition of fibre.