Investigating CO2 sequestration properties of biochar shotcrete.

The construction industry is a major contributor to CO 2 emissions, accounting for 5–7 % of worldwide CO 2 emissions. Biochar, a carbon-based material derived from waste, is considered an effective way to sequester carbon dioxide. This study investigated the effect of different biochar content on shotcrete under various curing conditions (carbonation, normal and low temperature). Flowability, compressive strength, splitting strength and microstructure of sprayed biochar shotcrete were conducted. Combined carbonation depth, thermogravimetric, and X-ray diffraction (XRD) were used to analyze the carbon sequestration of the biochar sprayed concrete materials from both macro and microscopic perspectives. In addition, the effect of low temperature on the performance of biochar shotcrete was considered. Results show that biochar fills the pores of the concrete and makes the microstructure denser when 5 % biochar replaces cement. Meanwhile, the compressive and splitting strength of concrete has been enhanced. The addition of 10 % biochar has a greater carbon sequestration capacity, although it can somewhat weaken the mechanical properties of concrete. Furthermore, low temperature hurt the performance of concrete. These results demonstrate the potential of combining biochar with shotcrete. It also provides a new direction for improving buildings' overall carbon sequestration performance. [Display omitted] • Effect of biochar content on the mechanical properties of shotcrete was compared. • Carbon sequestration of biochar shotcrete under carbonation curing was analyzed. • Temperature affecting the properties of biochar shotcrete was investigated. [ABSTRACT FROM AUTHOR]