水泥砂浆TSA侵蚀破坏过程的性能演变

研究了不同水灰比的掺石灰石粉水泥砂浆在低温硫酸盐溶液中长期浸泡后的外观、强度与矿物成分变化过程，分析了水泥砂浆受TSA侵蚀后的宏、微观性能演变规律．结果表明：TSA侵蚀是一种由外及里、逐渐发展的腐蚀破坏过程，降低水灰比可有效减缓TSA侵蚀破坏速率．从微观角度分析，将TSA侵蚀过程分为四个阶段：离子迁移期，钙矾石生成期，石膏生成期和碳硫硅酸钙生成期．根据力学性能变化与外观破损过程，TSA侵蚀又可分为三个阶段：潜伏期、膨胀开裂期和软化解体期。

Performance development of cement mortar subject to thaumasite form of sulfate attack

Limestone filler cement mortars with different water-cement ratios were immersed in sulfate solutions at a low temperature for a year,and their appearance,strength and mineral composition were measured at different immersion ages.The developments of microstructure and macro-performance of mortar were analyzed when exposed to thaumasite form of sulfate attack(TSA).The results show that TSA gradually develops from the outer to the inner of mortar,and the reduction of water-cement ratio effectively mitigates TSA on mortar.According to the microstructure development of mortar,TSA includes the following four procedures: diffusion of ions,ettringite formation,gypsum formation and thaumasite formation.On the basis of mechanical property development and visual deterioration of mortar,TSA is divided into three stages: latent period,swelling and cracking period and softening and decomposition period.