矿物掺合料对硅酸盐水泥净浆氯离子结合能力的影响

Influence of Mineral Admixtures on Chloride Binding Capacity of Portland Cement Paste

以掺粉煤灰(FA)和粒化高炉矿渣粉(GGBS)的硅酸盐水泥净浆为研究对象,开展其在不同浓度NaCl溶液中的浸泡试验.通过硝酸银滴定、X射线衍射(XRD)和热力学模拟,分析了溶液中氯离子浓度和水泥净浆中各物相含量的变化特点.结果表明:GGBS和FA的掺入可降低溶液中氯离子浓度,提高水泥净浆的氯离子结合能力;且GGBS可提高水泥净浆中水化铝酸钙(AFm)相含量及其对氯离子的化学吸附能力;FA可提高水泥净浆中水化硅(铝)酸钙C-(A)-S-H凝胶的物理吸附能力,当FA掺量为40%时,其物理吸附能力达到最大.

Some Portland cement pastes with different contents of fly ash(FA)and ground granulated blast furnace slag(GGBS)were immersed in NaCl solution with different concentrations for corrosion experiments.Through silver nitrate titration,X‑ray diffraction(XRD)and thermodynamic simulation,the variation rule of free chloride concentration in solution and the contents of various phases in cement pastes were analyzed.Results show that addition of FA and GGBS will reduce free chloride concentration in NaCl solution and improve the chloride binding capacity of hardened cement pastes.Addition of GGBS will result in an increase of AFm phase and an improvement of chemical binding capacity of chloride in hardened cement pastes.Meanwhile FA can improve the physical binding capacity of C-(A)-S-H in hardened cement pastes,the hardened cement paste with FA content of 40% has the optimum physical binding capacity of chloride.