Feasibility of utilizing rice husk Biochar as a supplementary cementitious material in concrete blocks

Abstract

Rice husk is one of the major byproducts of agriculture. This research is conducted to evaluate the feasibility of rice husk biochar (RHB) integrated concrete blocks and normal M30 grade concrete blocks through compressive strength test performance. RHB is used in this research as a supplementary cementitious material (SCM) in concrete blocks. The rice husk was pyrolyzed by burning in a muffle furnace with limited or no oxygen conditions under 700°C temperature. Blocks with the dimensions of 150mm×150mm×150mm were made according to the BS 1881 108 1983 standard. The RHB integrated blocks were made by replacing 1 wt.% of the weight of cement with RHB. Three RHB integrated blocks and three normal concrete blocks (as control blocks) were made. The concrete blocks were made using M30 Grade with a volume ratio of cement: sand: coarse aggregate, 1:1:2 accordingly, and the cement to water weight ratio was taken as 1:0.5. One of each control concrete block and RHB integrated concrete block were put into a water bath to cure for 7, 14 and 28 days accordingly. Then the compressive strength test was performed on each block. Although the compressive strengths of RHB integrated blocks were lower compared to normal concrete blocks, the compressive strength of 7, 14 and 28 days cured blocks had acceptable compressive strength above 30MPa.