复掺矿料高寒隧道泵送混凝土优化设计与性能  

Optimum Design and Performance of Pumping Concrete Mixed with Composite Mineral Material for Tunnel in Alpine Region

作　　者：郭寅川[1] 郝宸伟 郭昊田 张敬 王路生 GUO Yin-chuan;HAO Chen-wei;GUO Hao-tian;ZHANG Jing;WANG Lu-sheng(Key Laboratory for Special Area Highway Engineering of Ministry of Education,Chang'an University,Xi'an Shaanxi 710064,China;Inner Mongolia Transport Design and Research Institute Co.,Ltd.,Huhehot Inner Mongolia 010010,China;Wulanchabu Highway Engineering Quality Supervision Station,Wulanchabu Inner Mongolia 012000,China;China Road and Bridge Co.,Ltd.,Beijing 100000,China)

机构地区：[1]长安大学特殊地区公路工程教育部重点实验室,陕西西安710064 [2]内蒙古交通设计研究院有限责任公司,内蒙古呼和浩特010010 [3]乌兰察布市公路工程质量监督站,内蒙古乌兰察布012000 [4]中国路桥工程有限责任公司,北京100000

出　　处：《公路交通科技》2021年第1期112-120,共9页Journal of Highway and Transportation Research and Development

基　　金：住房和城乡建设部2019年科学技术计划项目(2019-K-035)。

摘　　要：针对高寒地区隧道所处的气候环境,结合二次衬砌结构要求,进行了掺复合矿料隧道机制砂泵送混凝土配合比的两阶段优化设计。第1阶段以和易性和力学性能为优化设计控制指标,采用正交试验方法,对9组含有不同水灰比、砂率、单位用水量的泵送混凝土坍落度和抗压强度进行了研究。第2阶段以耐久性为优化设计控制指标,利用单因素变量法,对10组不同粉煤灰(F)、矿渣微粉(S)和复掺F-S掺量的泵送混凝土抗冻性和抗渗性进行了测试和分析。对复掺F-S高寒区泵送混凝土界面区结构进行了扫描电镜观察,利用压汞试验对其孔结构参数进行了测试,进而分析了复掺F-S改善泵送混凝土耐久性的微观机理。结果表明:当水灰比、砂率、单位用水量分别为0.48,42%,198 kg/m3时,泵送混凝土的和易性和力学性能最佳;单掺适量粉煤灰、矿渣微粉和复掺F-S均可有效提升泵送混凝土的耐久性,当复掺F-S为30%时,泵送混凝土的抗冻性和抗渗性最优;复掺F-S改善机制砂泵送混凝土的界面区结构和孔结构的原理分别为:矿渣微粉和粉煤灰分别在早期和后期参与了水化反应,生成较为致密C-S-H凝胶和C-A-H晶体等水化产物,增强了界面区强度;矿渣微粉和粉煤灰的微集料填充效应和致密的水化产物细化了泵送混凝土的孔结构,减少了水分和有害离子的渗入。In view of the climatic environment of tunnels in alpine regions and the requirements of secondary lining structure,the two-stage optimization design of the mixing ratio of machine-made sand pumping concrete with composite mineral for tunnel is carried out.In the first stage,taking workability and mechanical properties as the optimal design control indicators,the slumps and compressive strengths of 9 groups of pumping concrete with different water-cement ratios,sand ratios and unit water consumptions are studied by orthogonal test.In the second stage,taking durability as the control indicator of optimal design,the frost resistance and impermeability of 10 groups of pumping concrete with different contents of fly ash(F),slag powder(S)and F-S are tested and analyzed by single factor variable method.The interface structure of pumping concrete with F-S in alpine region is observed by SEM,the pore structure parameters are tested by mercury injection experiment,the microscopic mechanism of F-S to improve the durability of pumped concrete is analyzed.The result shows that(1)when the water-cement ratio,sand ratio and unit water consumption are 0.48,42%and 198 kg/m3 respectively,the workability and mechanical properties of pumped concrete are the best;(2)the durability of pumping concrete can be effectively improved by adding proper amount of fly ash,slag powder or F-S separately,and the frost resistance and impermeability of pumping concrete are the best when the F-S content is 30%.The principles of improving the interface structure and pore structure of machine-made sand pumping concrete by mixing F-S are as follows:(1)slag powder and fly ash participated in the hydration reaction in the early and late stages respectively,forming denser C-S-H gels and C-A-H crystals and other hydration products,enhancing the strength of the interface;(2)the micro aggregate filling effect and the dense hydration products of slag powder and fly ash refined the pore structure of pumping concrete and reduced the infiltration of water and ha

关 键 词：隧道工程 优化设计 正交法 泵送混凝土 高寒地区 耐久性 

分 类 号：U455.91[建筑科学—桥梁与隧道工程]