Preliminary Study of Agricultural Waste as Biochar Incorporated into Cementitious Materials

Abstract

Incorporating small amounts of biochar into cementitious materials has partial effects on the environment. In this present study, rice husk was collected as agricultural biomass from a local area of Roorkee Uttarakhand, which contains siliceous material to a significant extent. Biochar was prepared from agricultural waste in a muffle furnace at a temperature of 500 ℃ for 90 min and ground to a fineness of less than 10 µm. Prior to incorporation into building envelopes such as mortar and concrete, a basic study on cement pastes is essentially required. For this purpose, different dosages of biochar such as 0, 3%, 5% and 10% wt. were replaced with cement in cementitious materials. Physical properties such as water absorption, density and porosity were investigated. Furthermore, mechanical and thermal properties such as compressive strength and thermal conductivity were studied. Advanced tools like field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and thermogravimetric analyzer (TGA) were used to identify the hydration products. As the dosages increased in the cement matrix, the physical properties of sample were increased and porosity decreased. The compressive strength of biochar incorporated cement paste improved according to 0, 3%, 5% and 10% wt. It further reveals that as the dosage increased, the thermal conductivity of the samples decreased significantly. Moreover, the sustainable assessment showed that biochar could reduce embodied carbon, embodied energy and strength efficiency substantially over the control sample. A satisfactory result was obtained at 5% wt. and 10 % wt. of biochar. The overall result revealed that biochar up to 10% wt. can be incorporated into mortar and concrete due to better results than the control mix.