Improvement of mechanical properties and carbon sequestration effect of carbide slag-carbonization curing on cement-based materials

The construction industry is one of the main sources of global carbon emissions. Using industrial solid waste calcium carbide slag (CCS) to replace part of cement clinker and combining it with carbonization curing technology is an important way to achieve carbon reduction and resource recycling. This paper studies the effect of different CCS dosages on the performance of ordinary Portland cement (OPC) in combination with carbonation curing, and explains the synergistic effect of its mechanical properties, microstructural changes and carbon fixation capacity. The results demonstrate that: (1) The addition of CCS will reduce the mechanical strength, while the addition of 5 % CCS during carbonation curing can increase the 28-day compressive strength by about 18 %; (2) CCS significantly extends the carbonation depth, and the CO2 absorption can reach 25.91 % at a CCS dosage of 20 %; (3) Microscopic mechanism analysis shows that the carbonation product is mainly calcite CaCO3, which can fill the voids and optimize the structure, but the excessive generation of carbonation products will cause volume expansion and destroy the integrity of the matrix. Through the research in this article, it can be found that the addition of an appropriate amount of CCS combined with carbonation curing can synergistically improve the mechanical properties and carbon fixation efficiency of cement-based materials.