The depletion of natural sand resources occurs due to excessive consumption of aggregate for concrete production. Continuous extraction of sand from riverbeds permanently depletes fine aggregate resources. At the same time, a major ecological challenge is the disposal of agricultural waste ash from biomass burning. In this study, an environmental friendly solution is proposed to investigate the incorporation of wheat straw ash (WSA) by replacing 0, 5, 10, 15, and 20% of sand in concrete. Characterization results of WSA revealed that it was well-graded, free from organic impurities, and characterized by perforated and highly porous tubules attributed to its porous morphology. A decrease in fresh concrete density and an increase in slump values were attained by an increase in WSA replacement percentage. An increasing trend in compressive strength, hardened concrete density, and ultrasonic pulse velocity was observed, while a decrease was noticed in the values of water absorption with the increase in WSA replacement percentages and the curing age. The WSA incorporation at all replacement percentages yielded concrete compressive strength values over 21 MPa, which complies with the minimum strength requirement of structural concrete as specified in ACI 318-19. Acid resistance of WSA incorporated concrete improved due to the formation of pozzolanic hydrates as evident in Chappelle activity and thermogravimetric analysis (TGA) results of WSA modified composites. Thus, the incorporation of WSA provides an environmentally friendly solution for its disposal. It helps in conserving natural aggregate resources by providing a suitable alternative to fine aggregate for the construction industry.
Keywords: Chapelle activity; aggregate resources; depletion; pozzolanic hydrates; structural concrete; thermogravimetric analysis; wheat straw ash.