Experimental Study on Self-Compacting Concrete using Glass Fibre

Self-compacting concrete (SCC) flows under its own weight and fills the formwork without vibration. This paper reports an experimental study on M20 SCC designed by IS 10262:2009, with glass fibre added at 0, 0.25, 0.5, 0.75, 1.0 and 1.25%. Fresh properties were measured by the slump flow, T50cm, V-funnel and L-box tests, and the compressive, split tensile and flexural strengths were measured at 3, 7 and 28 days. As the fibre content rises, the slump flow falls from 650 to 520 mm and the T50cm time rises from 6.82 to 14 s. The 0.5% mix gave the highest strengths at 28 days: 38.29 N/mm² in compression (28.2% above the plain SCC), 4.54 N/mm² in split tension (35.5% above) and 12.00 N/mm² in flexure (38.1% above). At 1.0% and 1.25% the compressive strength falls to 21.30 and 16.53 N/mm², below the plain SCC. The stiffness measured in the modulus test differs by no more than 2.5% between mixes. The optimum glass fibre content is therefore 0.5%, although the flexural values are unusually high and should be re-checked.