Influence of industrial waste, uncalcined rice husk, and sand on the mechanical strength of geopolymer cement for additive manufacturing

Abstract

Concrete is the second most consumed material globally, and Portland cement production contributes about 8% of CO₂ emissions, emphasizing the need for developing low-carbon binders for structural and additive manufacturing applications. This study proposes a standardized approach for evaluating geopolymer concrete (GPC) mix designs using a preset binder combined with industrial and agricultural waste.Crushed and uncalcined rice husk powder was incorporated to reduce embodied energy and density while assessing its effects on reactivity and performance.

Compressive strength testing, Scanning electron Microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS) analyses were used on precursor and cured samples to examine mechanical behavior and microstructural features. The mixture containing Uncalcined Rice Husk, industrial waste, and water achieved the highest compressive strength (30.45 MPa). Results demonstrate that combining industrial waste with rice husk can produce high-strength, low-carbon GPC composites suitable for additive manufacturing and construction.