The influence of biochar addition on the mechanical performance, hydration mechanism, and carbonation capacity of Super Sulfated Cement
Shuai Xiao, Yucheng Li, Chongxi Xu, Jianying Deng, Luqing Cheng, Hao Zhang, Yang Zhou, Jinxiang Hong
Abstract
The integration of Carbon Capture, Utilization, and Storage with building materials has become an important pathway for CO 2 reduction in the construction industry. The deficiencies of high carbon emissions of Ordinary Portland Cement and limited carbonation confined to the surface, limit its life cycle carbon emissions to a high level. Composed of industrial waste and gypsum, the Super Sulfated Cement has lower carbon emissions. Nevertheless, the slow dissociation of the Ca phase in super sulfated cement hinders both its strength development and CO 2 absorption capabilities. By incorporating biochar, this study fabricates a high-performance cementitious material with near-zero emissions. It demonstrates that biochar promotes hydration, leading to improvements of 16.2 % and 28.9 % in compressive and flexural strength , respectively. Furthermore, the unique microstructure of biochar facilitates CO 2 transport, significantly enhancing carbon absorption capacity , with carbonation depth increased by 85.19 % and carbonation product amount increased by 10.63 %. As a result, the GWP of the system can be decreased to 53.3 kg·CO 2 ·eq/m 3 , only 11.17 % of OPC's emissions, marking an 88.83 % and 65.31 % reduction compared to OPC and SSC, respectively. This work may inspire the development of near-zero or even negative carbon emission construction materials.