矿物掺合料对混凝土抗冻性的影响.pdfVIP

学兔兔 2011年 第 5期 (总第 259期 ) 混 凝 土 原材料及辅助物料 MATERIAL AND ADMINICLE Number 5 in 201 1(Total No．259) Concrete doi：10．3969~．issn．1002—3550．201 1．05．019 矿物掺合料对混凝土抗冻性的影响 周立霞，王起才 (兰州交通大学，兰州 730070) 摘 要：通过硬化水泥浆体孑L结构、混凝土力学性能和抗冻融指数等项目的测试，研究了孔结构对不同强度等级混凝土抗冻性的影响。 结果表明：直径小于20 nm的孑L与混凝土的强度及抗冻性均成正关联，为无害孔；直径大于20 nm的孑L与混凝土的强度及抗冻性均成负关 联，为有害孔；硅灰和粉煤灰双掺及硅灰、粉煤灰和矿渣三掺对水泥浆体孔结构均产生不同程度的影响，可以减少有害孔，增加无害孔，同 时还可以降低孔隙率，减小平均孔径及最可几孔径，增大孔表面积。在混凝土中掺人矿物掺合料进行孑L结构的细化和优化是提高混凝土抗 冻性的重要途径。 关键词：水工材料；抗冻性；试验分析；混凝土；孑L结构；矿物掺合料；灰色关联分析 中图分类号：’TU528．04l 文献标志码： A 文章编号： 1002—3550(2011)05—0053—04 Effect of mineral admixture on the frost resisttance of concrete ZHOULi-xia，WANGQi—cai (Lanzhou JiaotongUniversity，I an 0u 730070，China) Abstract： The pore structure Oil the frost resistance of different--strength-·grade concretes were investigated by means of the mercury intrusion porosimetry of the cement pastes．the mechanical tests and the index of freeze thaw resistance of the concretes．The results show that the volume fraction of 1ess than 20 nm pore has the positive effect on the compressive strength and frost resistance of the concrete，and the less than 20 mm pore is the harmless pore．The volume fraction ofgreater than 20 nm pore has the negative effect on the compressive strength and frost resistance of the concrete，and the greater than 20 n／／l pore is the harmful pore．The pore structure of the cement pastes are greatly influenced by the mixture of silicafume(SF)andfly ash(