A comprehensive review of the physical and mechanical characteristics of agricultural by-products as cementitious alternatives in the production of sustainable concrete

Abstract

In recent times the construction industry has been more focused on the development of sustainable/green structures to address the Sustainable Developmental Goals (SDGs) from environmental pollution aspects caused by the production of cement as well as the conventional methods of construction. Investigations have been carried out by incorporation of alternative cementitious materials than cement, possessing pozzolanic characteristics leading to enhanced binding capability within the cement-aggregate matrix and improved compressive strength as per the desired national or international standards. These alternative cementitious materials are not only limited to manufacturing or power industry by-products viz. fly ash, quarry dust, blast furnace slag, etc. but also the by-products of the agricultural industry have been the focus of research as these possess a rich amount of Silica (SiO2) content leading to pozzolanic reactivity during the curing period and contributing to the strength of concrete. The majority of these by-products that are investigated are rice husk ash (RHA), coconut shells, palm oil fuel ash (POFA), and sugarcane bagasse ash (SCBA), as a replacement for either cement or aggregate as well as used as admixtures to a certain extent. The present work illustrates an agglomeration of previous research conducted by different authors, thereby elucidating the findings of various agro-waste usage in the production of concrete and investigating their mechanical behavior. Furthermore, specific attention is exemplified towards the behavioral response of paddy straw when used in the cement-aggregate mixture in terms of microstructural and mechanical properties aspects. In this review article, illustrations are made with additional attention to reveal the role of chemical and physical attributes of the agricultural by-products, impacting the characteristics of concrete.