Recycling Agricultural Wastes in Concrete: Maize and Sorghum as examples

Abstract

Agricultural crops produce large amount of agricultural wastes. Some of these wastes are reused as fertilizers for the agricultural areas, but the remaining amount which represents the majority of the wastes is incinerated in uncontrolled and random ways and has a negative impact on the environment.One of these methods is to burn the maize and sorghum wastes to get rid of the stalks and corn cob after use. This process results in excessive production of carbon dioxide that pollutes the environment significantly. This study aims to investigate the use of Corn Cob Ash (CCA) and Sorghum Stalks Ash (SSA) as a partial replacement of cement in concrete. XRF chemical analysis was carried out on both SSA and CCA, and the results showed that both materials contained high percentages of silica oxide which indicates that these ashes can exhibit pozzolanic activity. In this study, the ashes of sorghum stalks and corn cobs were used to partially replace the cement in mortar and concrete mixtures. For mortar mixtures the replacement ratios were 5%,10%,20% and 40% while in concrete mixtures the replacement ratios were 5%,10% and 20%. Different concrete and mortar mixtures were tested in compression at different ages and the results showed that CCA and SSA can be used as a partial replacement of cement in both mortar and concrete as there was a significant improvement in the compressive strength, as for mortar mixtures the maximum increase in strength was 22% while maximum increase in strength of concrete mixtures was 30%.

Keywords

• agricultural wastes ash
• recycling
• sustainability