塔里木大学学报

本研究使用硅灰等质量(0%、5%、10%、15%)替代水泥制作现浇混凝土试件，开展试件在不同浓度(0%、3%、5%、10%)Na_2SO₄溶液中的全浸泡腐蚀试验，探究硅灰掺量对现浇混凝土抗硫酸盐侵蚀性能的影响。研究结果表明：1)硅灰的掺入使现浇混凝土试件内部C-S-H凝胶的生成量增加，密实度增大，SO₄^2-的渗透能力减小，钙矾石含量降低，试件抵抗硫酸盐侵蚀的能力增强。2)硅灰掺量为15%时，试件的表观形貌完整，抗压强度最高，相对动弹性模量变化和质量变化率最小，在硫酸盐溶液中的抗侵蚀性能最好。3)在侵蚀龄期达270 d时，硅灰掺量为15%的试件内部结构更加平整、密实，钙矾石和Ca(OH)₂晶体含量均明显比未掺硅灰组试件的低，这与试件宏观耐久性能指标的变化规律一致。研究成果可为新疆南疆盐渍土地区硅灰改性现浇混凝土的工程应用提供参考依据。

In order to study the influence of sulfate resistance of silica fume content on cast-in-place concrete, the specimens were prepared by replacing cement with silica fume at equal mass ratios(0%, 5%, 10%, 15%), and the full immersion corrosion tests were carried out in Na_2SO₄ solutions with different concentrations(0%, 3%, 5%, 10%). The results showed that: 1)The incorporation of silica fume increased the amount of C-S-H gel generated within specimens, enhanced compactness, reduced porosity and SO₄^2- permeability, lowered ettringite content, thereby improving sulfate resistance. 2)The specimens with a 15% substitution rate had intact surface morphology, the highest compressive strength, the smallest changes in relative dynamic elastic modulus and mass, and the optimal sulfate resistance. 3) After 270 days of erosion, the specimens with 15% silica fume content had a smoother and denser internal structure, the content of lowered ettringite and Ca(OH)₂ crystals was significantly lower than specimens without silica fume, which was consistent with the change rule of the macroscopic durability performance indexes. These findings can provide a reference for the engineering application of silica fume modified cast-in-place concrete in saline soil area of Southern Xinjiang.