复掺矿物掺合料混凝土抗氯盐侵蚀与抗冻性试验研究

发布时间：2018-12-29 19:08

【摘要】：为研究矿物掺合料对混凝土耐久性能影响,分别对单掺粉煤灰、双掺粉煤灰和硅灰、三掺粉煤灰、硅灰和矿渣微粉3种情况下混凝土抗压强度、电阻率、氯离子扩散系数以及抗冻性能进行了试验研究。此外,通过对试件进行电镜扫描,揭示了矿物掺合料对混凝土微观结构的影响。结果表明:矿物掺合料可以改善混凝土孔结构,提高密实性。掺入矿渣微粉混凝土3 d抗压强度略低,但7、28 d强度增长明显,28 d强度分别比单掺和双掺试件提高3.80%、43.29%;硅灰和矿渣微粉均能显著提高混凝土抗氯离子渗透能力,双掺和三掺混凝土试件氯离子扩散系数分别比单掺试件降低69.16%、83.13%;硅灰可以提高混凝土抗冻性,双掺混凝土比单掺抗冻耐久性系数提高3.86%;同时混凝土电阻率和氯离子扩散系数之间存在线性负相关关系。在冻融循环过程中,混凝土动弹性模量与质量损失和动弹性模量损失均存在负相关性。
[Abstract]:In order to study the effect of mineral admixtures on the durability of concrete, the compressive strength and resistivity of concrete with single fly ash, double fly ash and silica fume, triple fly ash, silica fume and slag micro-powder were studied. The diffusion coefficient and freezing resistance of chloride ions were studied. In addition, the effect of mineral admixtures on the microstructure of concrete was revealed by scanning electron microscope. The results show that mineral admixtures can improve the pore structure and compactness of concrete. The compressive strength of concrete mixed with slag micro-powder in 3 days was slightly lower, but the strength in 728 days increased obviously, and the strength in 28 days was increased by 3.80% and 43.29 respectively compared with the single and double mixed specimens. Both silica fume and slag powder can significantly improve the chloride penetration resistance of concrete. The chloride diffusion coefficient of double and triple doped concrete specimens is 69.16% and 83.13% lower than that of single concrete sample respectively. Silica fume can improve the frost resistance of concrete, and the durability coefficient of double mixed concrete is 3.86 higher than that of single concrete, and there is a linear negative correlation between the resistivity of concrete and the diffusion coefficient of chloride ion. During freeze-thaw cycle, there is a negative correlation between dynamic elastic modulus of concrete and mass loss and dynamic elastic modulus loss.
【作者单位】：大连海事大学道路与桥梁工程研究所;
【基金】：国家自然科学基金资助项目(51178069) 辽宁省交通科研项目(201310) 教育部新世纪优秀人才基金项目(NCET-11-0860)
【分类号】：TU528.01

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