Study on strength and durability characteristics of nano-silica based blended concrete

Abstract

The present paper highlights on the strength and durability characteristics of blended concrete mixes in different strengths of concrete. A lot of research is being carried out all over the world on various supplementary cementitious materials (SCMs) using various combinations which could be best suitable to achieve strength and durability aspects. Very few emphasized on the usage of Nano-silica as one of the SCMs along with other materials in producing blended concrete mixes. Three SCMs were used in the present study namely fly ash, ground granulated blast furnace slag and Nano-silica as a partial replacement material of cement in various proportions to assess the performance of nano-silica in the development of blended concrete mixes. The great advantages in terms of environmental and economic aspects is the utilization of these three materials (since two of these materials are industrial by-products) point of view. The inclusion of Nano-silica as a SCM up to certain extent can enhance mechanical and durability properties of concrete. Concrete compressive strength increases as the content of Nano-silica increases. Nano-silica has a very high pozzolanic activity. Filling effect of Nano-silica notably influences the refinement of pore structure. The durability properties of blended cement concrete mix were examined by immersing the specimens to HCl and H2SO4 at 5% concentration. Acid Mass Loss Factor (AMLF) and Acid Strength Loss Factor (ASLF) and acid durability factor (ADF) were determined and the results were compared with control mix. Rapid Chloride penetration test (RCPT) on control mix and blended cement concrete were performed to assess the short term chloride ions penetration. From the results, it was shows that the practice of these mineral admixtures is having a beneficiary role on the strength as well as the durability properties. The results indicated that the utilization of these materials as a partial replacement of cement have significantly improved the compressive strength of blended concrete mix in by 36.91%, 27.82% and 19.35% in 29.58 ​MPa, 51.40 ​MPa and 72.33 ​MPa. The results indicated that there is a significant improvement in the mechanical properties, shown better resistance in acid environment and chloride ion penetration.