Behavior of Self-Compacting Concrete at Various Levels of Replacement to Fine Aggregate by Pond Ash and Quarry Dust

(SCC) Self-compacting concrete has become increasingly popular in construction due to its ease of placement and flow ability. However, challenges in concrete production include the high demand and cost of cement, environmental concerns, and the rapid depletion of natural river sand from excessive extraction. To address these issues, alternative materials like pond ash from thermal power plants and quarry dust from stone quarries are being explored as replacements for natural fine aggregates in SCC. This dissertation investigates the use of pond ash and quarry dust as partial substitutes for natural fine aggregate in SCC. The study involved replacing 0% to 30% of natural fine aggregate with pond ash and quarry dust at intervals of 10%, while maintaining a constant cement content 500 kg/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>, water content 200 liters. primary goal was to determine the optimal percentage of fine aggregate replacement to achieve the desired flow characteristics in SCC. Two SCC mixes, PQSCC20 and PQSCC30, were prepared and compared with a normal self-compacting concrete (NSCC00). Various fresh properties were evaluated using tests such as T-Slump, T500mm-slump, L-Box, U-Box, V-funnel, and V5min-Funnel, following EFNARC guidelines. Hardened properties were assessed through compressive strength and split tensile strength tests, and water absorption was measured by weight. The study found that replacing 20% of fine aggregate with pond ash and quarry dust (PQSCC20) was optimal. The fresh properties of all mixes met EFNARC specifications. For PQSCC20, the compressive strength was 35.85 N/mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, the split tensile strength was 3.09 N/mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 28 days, and the water absorption was within the acceptable limit (less than 0.5).