V3I1P72

“A Study on Fly Ash, Recycled Brick Aggregate and steel fibers in self-compacted concrete”

Sarfaraz Khan¹, Prof. Kamlesh Kumar Choudhary^2*

Abstract

This study investigates the fresh, mechanical and durability performance of self-compacting concrete (SCC) produced with partial replacement of natural coarse aggregate by recycled brick aggregate (RBA), partial replacement of cement by Class F fly ash (FA), and incorporation of steel fibers. A factorial experimental program included mixes with RBA replacement levels of 0%, 25% and 50%, fly ash replacements of 0% and 10%, and steel fiber contents of 0% and 0.5% by volume. Fresh properties were assessed using slump-flow, tests. Hardened properties evaluated were compressive strength (7, 28, 56 days), split tensile strength (28 days), flexural strength and toughness indices for fiber mixes. Fly ash improved flowability and reduced superplasticizer demand; RBA reduced 28-day compressive strength by 6–14% for 25–50% replacement but remained acceptable for non-critical structural applications; steel fibers significantly improved post-peak behavior and flexural toughness. On balance, SCC with 25% RBA + 10% FA + 0.5% steel fiber achieved the best trade-off between workability, strength and toughness. Recommendations and limitations are discussed.

Keywords:

Self-Compacting Concrete (SCC) , Natural Coarse Aggregate, Recycled Brick Aggregate (RBA), OPC 43 grade cement, Class F fly ash (FA), Steel Fibers, Compressive Strength, Tensile Strength and Flexural Strength.