Permeability of Sulfate Ions in Cementitious Materials Containing γ-Ca2SiO4 after Autoclave Curing and Accelerated Carbonation
Permeability of Sulfate Ions in Cementitious Materials Containing γ-Ca2SiO4 after Autoclave Curing and Accelerated Carbonation
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DOI：
10.3151/jact.9.223
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发表时间：
2011-10
影响因子：
2
通讯作者：
Tsuyoshi Saito;Saphouvong Khamhou;Tatsuya Yumoto;N. Otsuki
中科院分区：
文献类型：
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作者：
Tsuyoshi Saito;Saphouvong Khamhou;Tatsuya Yumoto;N. Otsuki
硫酸盐对混凝土结构的侵蚀在世界各地都是一个严重的问题，特别是在中东，那里的土壤中含有丰富的硫酸盐。因此，需要设计出具有高抗硫酸盐侵蚀能力的胶凝材料，因此对含γ-Ca 2SiO 4（γ-C2 S）胶凝材料的高耐久性进行了研究。作者提出了如下的高耐久性材料设计：水泥基材料与γ-C_2S混合，经蒸压和加速碳化，在蒸压硬化体中得到1.1nm的雪硅钙石，并在表面致密化。然而，这种新材料的抗硫酸盐性尚未研究。因此，本研究的目的是从反应产物和孔隙率的角度了解添加γ-C2 S、高压灭菌和加速碳酸化对硫酸根离子渗透性（对抗硫酸盐性至关重要）的影响。最小的硫酸根离子渗透是OPC被γ-C2 S置换率为80%的样品。加速碳酸化后球文石的生成抑制了硫酸根离子的渗透。另外，1.1nm雪硅钙石在硬化体中的溶解受到抑制。此外，在表面处的低Ca/Si C-S-H可以降低该表面的孔隙率，从而有助于抑制硫酸根离子渗透。
Sulfate attack on concrete structures is a serious problem around the world, particularly in the Middle East, where sulfate is abundant in soil. Design of a cementitious material with high sulfate resistance is thus required, leading to research on the high durability of cementitious materials containing γ-Ca2SiO4 (γ-C2S). The authors have proposed the following material design for high durability: a cementitious material mixed with γ-C2S and subjected to autoclaving and accelerated carbonation, to give 1.1nm tobermorite in the autoclaved hardened body, and densification at the surface. However, the sulfate resistance of this new material has not been investigated. Therefore, the purpose of the present research is to understand the effect of adding γ-C2S, autoclaving and accelerated carbonation on the permeability of sulfate ions (crucial for sulfate resistance), from the viewpoint of the reaction products and porosity. The smallest sulfate ion penetration was a sample with 80% replacement ratio of OPC with γ-C2S. Generation of vaterite following accelerated carbonation suppressed sulfate ion penetration. In addition, dissolution of 1.1nm tobermorite in the hardened body was inhibited. Also, low-Ca/Si C-S-H at the surface may reduce the porosity of this surface and thus contribute to the suppression of sulfate ion penetration.