高寒高海拔地区高强混凝土配合比设计研究

High-strength Concrete Mix Proportion Design in Cold and High Altitude Area

为了解决高寒高海拔地区高强混凝土工作性差及强度不足的问题,分别在平原地区和高寒高海拔地区以相同的原材料和配合比制作了高强混凝土试件,并对其工作性、抗压强度、动弹性模量、超声波波速、抗折强度进行对比分析,试验结果表明随着海拔高度的增加混凝土和易性、力学性质和耐久性能全面下降。为改善高寒高海拔地区高强混凝土的各项性能,通过掺入减水剂和掺入引气剂并降低水灰比两种方案优化配合比。结果表明:两种优化方案混凝土力学性能均满足规范要求,但后者混凝土试件更密实、抵抗冻胀能力更强,抗冻耐久性更好。因此,建议在高海拔高寒地区采用降低水胶比同时掺加引气剂的配合比方案。

In order to solve the problems of poor workability and insufficient strength of high-strength concrete in highaltitude and cold regions,high-strength concrete specimens were made with the same raw materials and mix proportion in plain area and high-altitude and cold area,and their workability,compressive strength,dynamic elastic modulus,ultrasonic wave velocity and flexural strength were compared and analyzed.The results show that the workability,mechanical properties and durability of concrete decrease with the increase of altitude.In order to improve the performance of high strength concrete in high altitude and cold area,the mix proportion is optimized by adding water reducing agent and air entraining agent and reducing water cement ratio.The results show that the mechanical properties of concrete in the two optimization schemes can meet the requirements of the specification,but the concrete specimens of the latter are denser,the frost heave resistance is stronger,and the frost resistance durability is better.Therefore,it is suggested to reduce the water binder ratio and add air entraining agent at the same time.