Investigation of Nanosilica Effect on Behavior of Reinforced Concrete Beams

Abstract

Nanosilica is one of the concrete admixtures that are used to enhance the mechanical properties of concrete and offer the opportunity to improve the behaviour of reinforced concrete beams. This study investigated the effect of adding nanosilica to concrete mixture on failure mechanism, load deflection curve, and load carrying capacity of reinforced concrete beams. Another objective was analysing the implications of nanosilica addition for fresh concrete mixture and compressive strength. The study considered four percentages of nanosilica:2.5%, 5%, 7.5%, and 10% by weight of cement. The study showed that adding more than 5% nanosilica decreased workability of the fresh mix remarkably. The compressive strength increased significantly up to 129.9% for 7.5% nanosilica addition compared with control mix. Beam tests indicated that the first cracking and the ultimate loads increased up to 7.5% due to the nanosilica content. The failure mode of the beams changed from brittle failure for 0, 2.5, and 5% ratios to ductile failure for 7.5 and 10% ratios.