Assessment of Nano Silica effects on Self-Compacting Concrete

Abstract

SCC has become the most revolutionary development in concrete construction and nanotechnology, which has attracted the interest of researchers, is considered as a special research prospective. The present work is carried out for self-compacting concrete M40 grade by replacing fly ash and nano-silica partially. The replacement of cement with fly ash is kept consistent in all the cases and the investigation focuses on the influence of distinct nano-silica (nS) percentages on the mechanical properties of hardened Self-Compacting Concrete (SCC). Detailed investigation has been carried out by substituting cement with 0.5% increment of Nanosilica from 0% till 2% i.e., at 0%, 0.5%, 1.0%, 1.5%, 2.0% for 7days, 14 days, 28 days, 56 days, 91 days and compressive, flexural and split tensile strengths have been studied. These strengths are further evaluated at 28 days for 3%, 4% and 6% Nanosilica replacements. Compared to the conventional mix, the presence of nano-silica with SCC showed an improvement in all the strengths of SCC. The enhancements in the strengths were prominent up to 4% and there was a decline in the strengths at 6% replacement of nS. The substantial improvement in the strengths of hardened SCC with Nanosilica was due to the smaller size of nano-silica particles which improves the pore structure characteristics. However, the addition of Nanosilica at 6% can cause agglomeration when mixed into SCC and hence, a reduction in the strengths is noticed. Nanosilica can also open the way to environmental preservation by maintaining the same strength with lesser cement content than conventional SCC.