Synergistic Enhancement of Strength and Toughness in Carbonated γ‐C 2 S Compacts via PVA‐Assisted Carbonation
Aifeng Gao, Zhichao Liu, Fazhou WangABSTRACT
γ‐C 2 S is a promising low‐carbon binder, but the intrinsic brittleness of carbonated γ‐C 2 S compacts significantly limits their structural application potential. To address this issue, polyvinyl alcohol (PVA) was introduced to promote carbonation, regulate the polymorphic evolution of calcium carbonate and refine the pore structure, thereby improving the mechanical strength and toughness. In this study, carbonated γ‐C 2 S compacts were prepared with different PVA dosages, and the role of PVA in the carbonation and toughening mechanisms was systematically investigated. Within the PVA dosage range of 0.08–0.32 wt.%, the carbonated γ‐C 2 S compacts achieved compressive strengths exceeding 125 MPa and flexural strengths exceeding 45 MPa. At a PVA dosage of 0.16 wt.%, the specimens exhibited the highest flexural strength of 54.5 MPa and the maximum fracture energy of 234.5 J/m 2 . Mechanistic analysis revealed that PVA facilitated Ca 2+ dissolution and enhanced carbonation, forming needle‐like aragonite and inducing a transition in pore size distribution from bimodal to trimodal patterns. These changes improved matrix densification and mechanical properties. These results demonstrate that PVA‐assisted carbonation provides a feasible strategy for mitigating the brittleness of carbonated γ‐C 2 S compacts and improving their potential for building‐material applications.