| Abstract: |
India produces around 620 million tonnes of agricultural waste every year a number that increases with each harvest season but hardly ever comes up in discussion of affordable construction materials. The present study examines the influence of four types of agricultural waste ashes (AWAs), specifically rice husk ash (RHA), sugarcane straw ash (SSA), bagasse ash (BGA) and corn Stover ash (CSA)) on some fresh and hardened properties of M40-grade concrete at levels of replacement to cement mass that ranged between 10% and 20%. Seven different mixes were prepared at a constant water-to-binder ratio equal to 0.45, and specimens were subjected to compressive strength tests after being cured for three, seven, 28, 56, and 90 days while control tests determined workability as well as the performance under specific conditions in terms of saturated surface dry density gain, water absorption sorptivity assessment and chloride migration along with rapid chloride penetration test (RCPT). The most convincing pozzolanic reaction was observed for RHA-based blends, where compressive strength after 90days achieved a value of 45.8MPa at 10% replacement 10.9% higher than the control blend (C_0). SSA with 10% exhibited the highest 90-day strength of all composites at an absolute value of 47.2 MPa, likely due to the significant amount of injudicious hydraulic CaO. Compared to the OPC control (3,820 Coulombs), all AWA-blended mixes showed lower chloride permeability results (RCPT values: 1,790 and 2,460 Coulombs) shifting classification from 'Moderate' for the control mix to 'Very Low' per ASTM C1202. Depending on the proportion of replacement level, the average savings in CO2 were 41.6–83 kg/m³ and unit cost indices decreased by up to 12.2%. |
