NANO MODIFIED HIGH VOLUME FLYASH SELF COMPACTING CONCRETE

Hemalatha, T, Maitri Mapa, Vinoth Kumar P

Abstract: Self compacting concrete (SCC) is an innovative concrete to tackle the problem of concreting through dense reinforcement. Adoption of SCC offers substantial benefits in enhancing construction productivity, reducing overall cost, and improving the work environment. The present work investigates the compressive strength of SCC by replacing high volumes of Portland cement by fly ash. Studies are conducted to investigate the influence of different replacement levels of cement (20%, 40%, 60% and 80%) with fly ash (class F). The results revealed that the fresh and hardened properties of SCC incorporating upto 40% fly ash as replacement of cement (CE40FA) are not significantly affected. However, it was noticed that the early age strength is significantly affected even at 40% replacement. To overcome the drawbacks of using high volume fly ash (HVFA), the additions such as lime water, lime sludge and nano CaCO3 etc. are added to HVFA SCC. It is understood that the additions of lime water, lime sludge and nano CaCO3 in CE40FA mix helps in improving the early age strength at 7 days without affecting the later age strength at 28 days. In CE40FA, SCC containing lime water showed about 38% higher compressive strength at 7 days. The addition of 5% lime sludge and 1% nano CaCO3 in CE40FA also showed about 31% and 58% increase in the strength compared to the ordinary concrete at 7 days, respectively.

Keywords: High volume fly ash, mechanical properties, nano CaCO3, Lime sludge

DOI: https://doi.org/10.15623/ijret.2015.0425015