高速冲击下混凝土动力学性质和动态温度研究

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Abstract：Inorder to studythedynamic mechanical propertiesofconcreteandthedynamic temperatureatthecrack under impact，steel-polypropylene fiber reinforced concrete （SPFRC）was taken as the research object using a self-built high-speed infrared temperature measurement system.The time resolution of the high-speed infrared temperature measurement system is inthe orderof microsecond.Theconcrete temperature curve wasfited bystaticcalibrationtest asareference.Combined with the Hopkinson pressure bar test device，the dynamic properties ofSPFRC specimens with diferent steel fiber contents and the dynamic temperature change at thecrack were studied.Theresults indicatea significant coupling effect between the temperature evolutionand mechanical propertiesoftheconcretespecimensandsubstantial influencesofthestelfibercontent onboth dynamicperformanceandtemperature.Specificallyasthesteelfbercontentincreases，thecompressvestrengthofthe concrete improves，reaching optimal mechanical performance at 1 . 5 % steel fiber content.However，at 2 . 0 % steel fiber content， the mechanical performance slightlydecreases due to an increase in internal voids within the concrete.During impact，the dynamic tempeatureefctatthecacklocationexibitsa“stepedpattm，withtemperaturechangeccurringintwodistinct stages：aninitialslowriseduringearlycrackformation，folowedbyasharpincreaseasfrictionandshearefects intensifywith crack propagation.The influence of varying steel fiber content on temperature change is limited， with peak temperature and peak stress showing similar trends.The primary temperature variationsare drivenbycrack propagationandfrictional efects. After impact， the overall temperature in SPFRC specimens continues to rise within the first .Due to the thermal lag， the temperature does not decrease immediately after unloading.The high-speed infrared temperature measurement system provides a newmethod forreal-time monitoring of temperaturechanges atconcrete crack locations，ofering abasis forassessing temperature evolution at cracks and the evaluation of crack propagation behavior.

Keywords：stel-polypropylenfiberreinforcedconcrete （SPFRC）； dynamic temperature； infraredtemperature measurement

钢-聚丙烯纤维混凝土（stee-polypropylene fiber reinforced concrete，SPFRC）是一种常用的脆性建筑材料，与普通混凝土相比，钢纤维的掺入提高了混凝土的强度、韧性等[1-5]，聚丙烯纤维的掺入抑制了裂纹的扩展、提升了混凝土的抗高温性能[6-8]，Kodur等[9] 等[10]、徐礼华等[1]、王秋维等[12]将钢纤维（steelfiber，SF）和聚丙烯纤维（polypropylene fiber，PF）混掺加入混凝土中，能够同时提升混凝土的强度和裂后性能。（剩余25128字）