硫铝酸盐水泥基材料抗碳化性能研究进展

Research Progress on Carbonation Resistance ofCalcium Sulfoaluminate Cement-Based Materials

碳化是复杂的物理化学过程,主要包括二氧化碳(CO_(2))在水泥混凝土中的扩散、溶解和与可碳化物质的反应,最终造成水泥混凝土碱性的降低和钢筋的锈蚀,显著影响其耐久性能。硫铝酸盐水泥(CSA)具有快硬早强、耐硫酸盐腐蚀性能优异等特点,但其抗碳化性能较差,易导致水泥内部化学组成的改变和微观结构的劣化,最终将严重危害基础设施的正常服役。因此,明晰影响CSA碳化的因素,揭示CSA碳化机理具有重要的工程和科研意义。首先从CSA的水化产物出发,介绍了三硫型水化硫铝酸钙(AFt)、单硫型水化硫铝酸钙(AFm)及水化硅酸钙(C-S-H)的碳化机理;其次分析了材料因素对CSA抗碳化性能的影响;最后综述了CO_(2)矿化养护对CSA性能的提升作用,总结了目前CSA碳化研究的不足,为进一步研究CSA抗碳化性能提升方法和碳化利用方式提出了建议。

Carbonation is a complex physical and chemical process,which mainly includes the diffusion and dissolution of CO_(2) in cement concrete and the reaction with carbonizable substances,which eventually leads to the decrease of alkalinity of cement concrete and the corrosion of steel bars,which significantly affects its durability.Calcium sulfoaluminate cement(CSA)has the characteristics of fast hardening,high early strength and excellent sulfate corrosion resistance.However,its poor carbonation resistance can easily lead to the change of chemical composition of hydrates and the deterioration of microstructure,which will seriously endanger the normal service of infrastructure.Therefore,it is of great engineering and scientific significance to clarify the factors affecting CSA carbonization and reveal the mechanism of CSA carbonization.Firstly,starting from the hydration products of CSA,this paper introduces the carbonation mechanism of calcium trisulphoaluminate hydrate(AFt),calcium monosulfoaluminate hydrate(AFm)and calcium silicate hydrate(C-S-H).Secondly,the influences of material factors on the carbonation resistance of CSA are analyzed.Finally,the effect of CO_(2) mineralization curing on the performance of CSA is reviewed,and the shortcomings of current CSA carbonization research are summarized,and suggestions for further research on methods of improving the carbonization resistance of CSA and the utilization of carbonization are put forward.