A Study On Mechanical And Rheological Properties Of Hybrid Fibre Reinforced Self Compacting Concrete

Abstract

Self-compacting concrete (SCC) is designed to flow and consolidate under its own weight, but the addition of fibres can change both fresh-state workability and hardened mechanical performance. This experimental study investigated M30 SCC reinforced with hybrid steel and polypropylene fibres. The programme included material characterization, SCC mix design, slump-flow and T500 testing, L-box and V-funnel testing, and compressive-strength testing of 150 × 150 × 150 mm cubes. The designed SCC used 312.9 kg/m³ cement, 926.5 kg/m³ fine aggregate, 910.299 kg/m³ coarse aggregate, 192 kg/m³ water, 0.6% PCE superplasticizer, and 0.3% VMA, with slag reported in the designed mixture. Slump flow was 620, 644, 650, 609, and 600 mm for the fibre additions reported from 0 to 1%, with the highest reported slump at 0.5%. L-box ratios ranged from 0.82 to 0.98 and V-funnel times from 6.8 to 8.7 s. For the designed M30 concrete, average compressive strength increased with the reported fibre level at 3, 7, 21, and 28 days; the maximum 28-day value was 39.11 N/mm² at 2% fibre. The thesis concludes that 1.5% hybrid fibre content provided the best balance between strength enhancement and workability.