An Insight into the Effect of Rice Straw Biochar on Compressive Strength and Thermal Conductivity of Cement

Abstract

It is well known that is very important to improve the quality of cement material concerning its compressive strength and thermal conductivity, which may reduce its quantity of usage and improve the heat maintenance of a structure compared with the traditional cement. In order to improve the properties of cement and other building materials, the test pieces were prepared by incorporating rice straw biochar with different pyrolysis temperatures into cement paste, and the compressive strength and thermal conductivity were tested after curing under both wet and dry conditions. The results showed that with the increase of biochar incorporation, the strength and thermal conductivity of the test blocks were decreased, but the thermal insulation performance of them was increased, and the quality and density of the test block were reduced. Under the condition of wet curing, the strength of the test pieces enhanced greatly with the dosage of 1% and 5%. When the dosage was 1%, the strength of the wet curing test block was the highest, which was increased by 51.06% compared with the blank control. The block strength increased by 14.98%; the thermal conductivity of the test piece incorporating biochar was reduced, and the test piece with 10% of the dry curing showed better thermal insulation performance, and the thermal conductivity was reduced by 39.21%. It can be seen that the addition of biochar improves the strength of the test block and optimizes the thermal insulation performance of the cement.