| Abstract: |
The growing construction globally has increased the demand for ordinary Portland cement (OPC) that is responsible for about 8% of global CO₂ emissions. In this empirical study efforts were made to develop green concrete by partially replacing OPC with two agricultural and industrial by-products Rice Husk Ash (RHA) and Blast Furnace Slag (BFS) in various proportions. For M30 grade concrete, six concrete mix designs were created using different RHA substitutes: 0%, 10%, 20% & 30%, along with BFS at 0% & 20%. Experimental studies were conducted to investigate fresh properties (slump, compaction factor, V-B time), mechanical properties (compressive strength at 7, 28 and 90 days; split tensile strength; flexural strength), and durability properties (water absorption, chloride ion permeability, sorptivity, carbonation depth and acid resistance). Statistical analyses (one-way ANOVA; Pearson correlation) quantifying the importance of material replacement on concrete properties, were carried out. The results indicated that a ternary blend containing 10% RHA and 20% BFS (mix GC-3) produced the best performance, with 28-day compressive strength of 41.3 MPa 8.1% higher than the control mix (38.2 MPa) and a markedly lower chloride permeability (2180 coulombs vs 3210 coulombs in control). Based on analysis of the carbon footprint by C-Designers, the result has shown that CO₂ relative to conventional concrete can potentially be reduced by up to30.4%. These findings are in support that RHA-BFS ternary green concrete could be a technically feasible and environmentally friendly alternative to OPC concrete. |
