高速沖擊下混凝土動力學(xué)性質(zhì)和動態(tài)溫度研究

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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

鋼-聚丙烯纖維混凝土（stee-polypropylene fiber reinforced concrete，SPFRC）是一種常用的脆性建筑材料，與普通混凝土相比，鋼纖維的摻入提高了混凝土的強度、韌性等[1-5]，聚丙烯纖維的摻入抑制了裂紋的擴展、提升了混凝土的抗高溫性能[6-8]，Kodur等[9] 等[10]、徐禮華等[1]、王秋維等[12]將鋼纖維（steelfiber，SF）和聚丙烯纖維（polypropylene fiber，PF）混摻加入混凝土中，能夠同時提升混凝土的強度和裂后性能。（剩余25128字）