Application of biochar from coconut and wood waste to reduce shrinkage and improve physical properties of silica fume-cement mortar

By Souradeep Gupta, Padmaja Krishnan, A. Kashani, H. Kua. 2020

171 citations recorded by the source corpus.

Abstract High autogenous and drying shrinkage associated with the use of silica fume increases the likelihood of cracking under warm climatic conditions and limits its application as a supplementary cementitious material. This research investigates the influence of biochar, added as a partial replacement of silica fume and cement, on shrinkage, hydration, strength and permeability of cement mortar. Biochars were prepared from wood waste and coconut shell and used as 5 wt% cement replacement and 33% replacement of silica fume, respectively. It was observed that combination of biochar (5 wt% of cement) and silica fume (10 wt% of cement) can reduce autogenous shrinkage and drying shrinkage by 61% and 23% compared to the mortar with only silica fume (15 wt%) at 91-day age. By comparison, it is found that biochar with higher permeability and lower pore tortuosity lead to a higher reduction in autogenous shrinkage. Biochar from wood and coconut shell added at 5 wt% of cement has been found to improve hydration, strength and water permeability of mortar compared to control. Combination of biochar and silica fume shows improved 28-day strength compared to control mortar and offers similar strength and water permeability as that of mortar with only silica fume (15 wt%). The research outcomes highlight the benefits of using biochar in high-performance concrete which can reduce the demand for Portland cement and silica fume.

Subfields: Civil and Structural Engineering

View Paper: https://www.semanticscholar.org/paper/b52e07ae7bf18828a53405fa5bb44b08ff98947f