International Journal of Waste Resources

Valorization of paper mill solid wastes: Partial replacement of cement by application of lime sludge and boiler ash synthesized nanosilica in concrete

5^th World Convention on Recycling and Waste Management

September 11- 12, 2017 Singapore

Prabhat Vashistha, Viveek Kumar and Sanjeev K Singh

Indian Institute of Technology Roorkee, India
Indian Institute of Technology Delhi, India
Central Building Research Institute Roorkee, India

Posters & Accepted Abstracts: Int J Waste Resour

Abstract:

Millions of tons of solid waste are generated by the paper industries all over the world. For the reduction of solid waste threat to the environment, its application as raw material in other industries could be the suitable option. In this study, lime sludge was used with boiler ash synthesized nanosilica in cement concrete. Boiler ash was used for nanosilica synthesis, due to the presence of silica precursor in boiler ash. Sol-Gel method was used to prepare the nanosilica with methanol as solvent. Highest amount of silica obtained with 1:27 precursor:methanol ratio and 9 days of ageing time. Lime sludge from recovery section of paper mill and boiler ash synthesized nanosilica is used in concrete to partially replace cement. The cement was replaced by lime sludge in the range of 10%, 20%, 25%, 30%, 35% and 40% by weight. These blends of concrete were also prepared with 2% and 4% by weight nanosilica application with lime sludge. Produced concrete mixtures were tested for compressive strength and compared with conventional concrete. Compressive strength were evaluated with 7, 28, 90 days of curing. As a result, the compressive strength of concrete with only lime sludge increased up to 20% with addition of lime sludge, after that compressive strength of concrete decreased with further addition of lime sludge. Concrete blends with addition of 2% nanosilica along with lime sludge achieved the increasing compressive strength till 25% replacement of cement and concrete blends with 4% of nanosilica application further get increment in limit for 30% of cement replacement. This study helps in developing the sustainable utilization of lime sludge and boiler ash in the construction activities.