Biochar-zeolite modified super sulphate cement as a high-performance, sustainable and high-efficiency CO₂ sequestration cementitious material

Abstract

Cement production contributes 8 % of global industrial carbon emissions, underscoring the urgent need for innovative strategies to mitigate its environmental impact. Super Sulfated Cement (SSC) is a promising low-carbon alternative, but its carbon sequestration potential remains underexplored. This study integrates biochar and zeolite into SSC to create a near-zero-carbon, high-performance composite with hierarchical transport pathways, enhancing compressive and flexural strength by 63.1 % and 43.8 %. A comprehensive mechanism for the composite's carbon sequestration is proposed, leveraging biochar's tunnel-like channels and zeolite's nano-pores, along with molecular sieve properties, to create a hierarchical pore structure. This structure facilitates CO₂ transmission to greater depths and enables lateral diffusion, increasing carbonation by 37 % and CO₂ uptake to 41.7 kg·CO₂/kg. Its Global Warming Potential is 51.08 kg·CO₂/kg, reducing emissions by 87 % and 51.1 % compared to Ordinary Portland Cement (OPC) and SSC, respectively. This study provides an innovative, scalable pathway to developing ultra-low-carbon cementitious materials, leveraging industrial and agricultural waste to enhance environmental sustainability. The findings offer actionable insights for advancing carbon capture technologies and achieving negative-carbon cement production. Synopsis: Integrating biochar and zeolite into supersulfated cement enhances CO₂ sequestration, reducing lifecycle carbon emissions and addressing solid waste valorization and air quality challenges.