自然风化作用下碳化养护水泥基材料的力学性能劣化机制OA

Carbonation curing can accelerate the early strength development of cement-based materials while sequestering carbon dioxide.However,the degradation mechanisms affecting their mechanical properties during service life remain unclear.This study exposed cement paste specimens to natural environmental conditions to investigate the effect of carbonation curing compared to conventional water curing under different weathering durations(30,60,and 90 d).The composition,pore structure,and both macroscopic and microscale mechanical properties of the weathered specimens were systematically analyzed.The results indicate that,in the later stage(90 d)of weathering,specimens carbonation curing for 0.5 h and 1 d show 15.1％and 34.7％higher compressive strength,and 1.4％and 3.6％higher average microhardness,respectively,than the conventional water curing specimens.This improvement is attributed to the formation of a dense carbonate layer in sample during carbonation curing.Moreover,with extended carbonation duration,the nanoindentation modulus at the specimen surface increases significantly.These findings demonstrate that carbonation curing significantly enhances the weathering resistance of cement-based materials,providing an important basis for its application in this field and a useful reference for the deployment of early-age carbonation curing products in coastal regions.