公路隧道衬砌高性能混凝土的高温烧损试验研究

Experimental research on the high-temperature burning of a highway tunnel lining made from high performance concrete

利用自行设计高温压力加载试验装置,研究了高温后受损衬砌高性能混凝土(HPC)残余抗压强度在不同条件下随温度劣化的规律和定量关系,建立了火灾后隧道衬砌HPC残余抗压强度与火场温度之间的数学关系式.研究表明:高等级的HPC强度很高,但其抗火性能很差;在高温过程中及自然冷却条件下,HPC残余抗压强度总体上呈降低趋势,在300℃时,C50HPC残余抗压强度有小幅增加;射水冷却条件下,HPC残余抗压强度随着温度升高一直呈衰减状态;相同加热温度等级条件下,高温过程中HPC的残余抗压强度略高于自然冷却后HPC的残余抗压强度,自然冷却后HPC的残余抗压强度高于射水冷却后HPC的残余抗压强度.

High performance concrete was burned at high temperatures in a custom made pressure test set. The deterioration of the concrete was studied at different temperatures and a quantitative relationship between residual compressive strength and temperature was obtained. The results show that higher grade, high performance concrete had poorer fire resistance. The residual compressive strength of the high performance concrete decreases under constant high temperatures or with natural cooling. A minor increase in compressive strength was noticed at 300℃. The residual compressive strength decreases as the temperature increases for water spray cooling. The residual compressive strength of the concrete at high temperature is slightly higher than after natural cooling; The residual strength after water spray cooling was lowest of the three conditions.