Engineering characteristics of agro-residue–based geopolymer concrete with fibre reinforcement
摘要
The creation of eco-friendly construction materials by utilising agro-industrial by-products presents a promising approach to lowering the carbon emissions of the building industry. This research explores the engineering behaviour of geopolymer concrete formulated with sugarcane bagasse ash, rice husk ash, and cow dung ash as aluminosilicate sources, further strengthened with basalt fibres in varying amounts (0–2.5%). A wide range of experiments was performed to assess mechanical performance (compressive, flexural, and split tensile strengths) and durability characteristics (chloride ion penetration, water absorption, and resistance to acid attack) over curing periods extending to 180 days. Results exhibited a clear parabolic relationship with fibre content, identifying an optimum dosage near 1% basalt fibre. The compressive strength increased from 50 to 62 MPa (24% improvement), flexural strength from 4.4 to 5.8 MPa (32% increase), and split tensile strength from 3.7 to 4.8 MPa (30% gain) at 180 days. Durability indicators also improved at the optimum fibre dosage: water absorption decreased from 8 to 5%, acid attack–induced mass loss reduced from 38 to 6%, and RCPT values dropped from 3100 to 1600 C, shifting chloride penetrability from moderate to low. However, fibre contents above 1.5% led to reduced workability, fibre clustering, and increased permeability. ANOVA confirmed the dominance of the quadratic fibre effect, with Fibre2 contributing 50–62% of the total variation across responses. Overall, the study demonstrates that basalt fibre–reinforced agro-waste geopolymer concrete not only satisfies structural and durability requirements but also advances sustainable construction by converting waste into resources and reducing dependency on Portland cement.