火灾后套筒灌浆料力学性能试验研究

Experimental study on mechanical properties of sleeve grouting material after fire

为研究火灾对套筒灌浆料力学性能的影响,设计不同受火时间(60,90 min),不同静置时间(1,14 d)以及不同冷却方式(自然冷却、喷水冷却)试验,分析不同工况下的套筒灌浆料的抗折强度和抗压强度。结果表明:随着受火时间的增加,套筒灌浆料的抗折、抗压强度均逐渐降低,自然冷却后抗折强度残余率分别为11.3%、9.1%,抗压强度残余率分别为48.4%、25.8%,抗折强度降幅更大;随着静置时间的增加,套筒灌浆料抗折强度逐渐降低,在自然冷却工况下抗压强度降低,降幅均为5.5%,而在喷水冷却工况下则升高,增幅分别为11.4%和7.3%;受火时间、静置时间以及冷却方式对套筒灌浆料抗折、抗压强度均产生不利影响,其中受火时间影响最大。试验结果可为火灾后装配式混凝土结构灌浆套筒连接节点的鉴定评估与加固设计提供依据。

In order to study the influence of fire on the mechanical properties of sleeve grouting material,the tests with different fire durations(60 min,90 min),different standing time(1 d,14 d)and different cooling methods(natural cooling,water spray cooling)were designed to analyze the flexural strength and compressive strength of sleeve grouting material under different working conditions.The results showed that with the increase of fire duration,both the flexural strength and compressive strength of sleeve grouting material decreased gradually.After the natural cooling,the residual rate of flexural strength was 11.3%and 9.1%respectively,and the residual rate of compressive strength was 48.4%and 25.8%respectively,with a greater decline in flexural strength.With the increase of standing time,the flexural strength of sleeve grouting material decreased gradually,and the compressive strength decreased by 5.5%under the natural cooling condition,while it increased by 11.4%and 7.3%respectively under the water spray cooling condition.All the fire duration,standing time and cooling method had adverse influence on the flexural strength and compressive strength of sleeve grouting material,and the fire duration had the greatest influence.The test results can provide the basis for the appraisal evaluation and reinforcement design on the grouting sleeve joint of prefabricated concrete structure after fire.