Use of different agro-waste ashes in concrete for effective upcycling of locally available resources

Abstract

Due to the high amount of carbon dioxide emission from conventional cement production, sustainable alternative cementitious materials are preferred in the construction sector. Earlier studies were focused only on the use of industrial by-products such as fly ash, slag and silica fume as alternative cementitious materials. A comprehensive review of the use of a wide range of agro-waste ashes is highly limited. Therefore, the present review focuses on the potential of several agro-waste ashes including sugarcane bagasse ash, rice husk ash, palm oil fuel ash, corncob ash, coconut shell ash, wood ash, groundnut husk ash, cassava peel ash, wheat straw ash, elephant grass ash, rice straw ash, sugarcane straw ash, tobacco ash and bamboo leaf ash as alternative cementitious materials in concrete. Physical, chemical and morphological characteristics of different agro-waste ashes and their influences in the blended cement concrete are presented. Besides, the effects of these agro-waste ashes on workability, strength, water absorption, sorptivity, porosity, permeability, drying shrinkage, resistance to acid and sulfate attacks of blended concretes are critically compared. Agro-waste ashes consist of silica content above 50% with the exception of tobacco ash and groundnut husk ash. Addition of the agro-waste ashes reduces the slump of concrete except for palm oil fuel ash, wheat straw ash and rice straw ash blended concretes. Significant reduction in the permeability and subsequent enhancement in the durability of agro-waste blended concretes are evidently witnessed.