EFFECT OF SILICA FUME AND STEEL FIBERS ON MECHANICAL AND DURABILITY PROPERTIES OF SELF-COMPACTING CONCRETE
Keywords:
Self-compacting concrete, silica fume, steel fibers, workability, J-ring, L-box, V-funnel, mechanical properties, compressive strength, tensile strength, flexural performance.Abstract
Self-Compacting Concrete (SCC) has a great potential as a long-awaited building material that allows easy placement without the use of mechanical vibration. This experimental study seeks to evaluate the synergistic impact of silica fume and Steel fiber on the fresh and hardened Properties of SCC. The study was divided into two parts: Part I evaluated SCC mixtures with partial cement replacement with silica fume at 0%, 5%, 10%, and 15% levels and Part II added 1% volume fraction of straight steel fibers into the same percentages of silica fume. Standard workability tests J-ring, L-box, and V-funnel were carried out in fresh properties, whereas in hardened properties, compressive strength, split tensile strength, and flexural strength tests (28 days) were performed. The results indicate that efficient mechanical performance improvement (∼20–25% increase in compressive strength) is achieved when using 10% silica fume replacement with respect to total cement weight under flow capacity of workability acceptance defined by EFNARC. Addition of 1% steel fibers has greatly effects on tensile and flexural properties (enhancement of around 15-20%) while workability characteristics remains almost the same. A composite material manifests high durability and ductility due to the pozzolanic reaction of silica fume and the mechanism of crack-bridging action of steel fibers. This work offers useful guidelines for the effective design of SCC mix for high performance structural applications, such as precast elements, bridges and heavily reinforced structural members.
