高温作用下轻骨料混凝土力学性能研究  

Study on mechanical properties of lightweight aggregate concrete under high temperature

作　　者：申海洋 刘凌晖 任磊 SHEN Haiyang;LIU Linghui;REN Lei(Shanxi Vocational University of Engineering and Technology,Jinzhong 030619,China;School of Civil Engineering,Central South University,Changsha 410075,China;Yuxiang Construction Engineering Co.,Ltd.,Taiyuan 034000,China)

机构地区：[1]山西工程科技职业大学,山西晋中030619 [2]中南大学土木工程学院,湖南长沙410075 [3]裕祥建设工程股份有限公司,山西太原034000

出　　处：《铁道科学与工程学报》2022年第10期2976-2983,共8页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51978669)。

摘　　要：由于火灾事故频发,给建筑消防领域带来严重的安全隐患,因此,建筑物的抗火设计逐渐成为结构设计中最为重要的环节。然而,针对轻骨料混凝土在高温作用下的静态和动态力学性能以及内部损伤情况的研究鲜有报道。为研究火灾高温对轻骨料(页岩陶粒)混凝土力学性能的影响,用陶粒替代部分粗骨料制备4组不同替代率参数的轻骨料混凝土,并在火灾高温至800℃的条件下对轻骨料混凝土试件分别开展抗压强度、劈裂抗拉强度试验和动态压缩性能试验,测试相应条件下试件的质量和相对动弹性模量。研究结果表明:在火灾高温作用下,轻骨料混凝土内部更加疏松,质量、抗压强度、劈裂抗拉强度和相对动弹性模量逐渐降低且随着温度的升高下降速率更快,当温度为800℃时,抗压强度和劈裂抗拉强度最大损失率分别为81.82%和69.72%;初始阶段高温作用改善了轻骨料混凝土内部微观结构,促进了火山灰及水泥的水化反应;但温度的升高使得胶凝结构内部较为疏松分散,水泥石和轻骨料的黏结强度有所降低,水泥石裂纹逐渐扩张发展,进而加剧强度的损失;从工程实际应用和火灾高温环境下轻骨料混凝土的力学性能角度考虑,建议轻骨料掺量在30%左右,当800℃高温作用时,强度损失率最低。Due to the frequent occurrence of fire accidents,the safety of building fire areas is serious.The design of fire resistance in buildings is gradually becoming the most important part of structural design.However,there are few reports on the static and dynamic mechanical properties and internal damage of lightweight aggregate concrete under high temperature.In order to study the influence of high temperature in fire on the mechanical properties of lightweight aggregate(shale ceramsite)concrete,four groups of lightweight aggregate concrete with different replacement rate parameters were prepared by substituting partial coarse aggregate with ceramsite,and the compressive strength,splitting tensile strength,and dynamic compression performance tests of the lightweight aggregate concrete specimens were respectively carried out under the condition of high temperature to 800℃in fire.The mass and relative dynamic modulus of the specimen were measured.The results show that the interior of lightweight aggregate concrete is more loose,and the mass,compressive strength,splitting tensile strength and relative dynamic modulus of elasticity decrease gradually under the action of high temperature,and the decrease rate is faster with the increase in temperature.When the temperature is 800℃,the maximum loss rates of compressive strength and splitting tensile strength are 81.82%and 69.72%respectively;At the initial stage,high temperature improves the internal microstructure of lightweight aggregate concrete and promotes the hydration reaction of pozzolanic ash and cement.With the increase of temperature,the internal structure of the cementitious structure becomes loose and dispersed,and the bond strength of the cement stone and light aggregate decreases,and the crack of cement stone gradually expands and develops,which further increases the loss of strength.Considering the engineering application and the mechanical properties of lightweight aggregate concrete in high-temperature environment,it is suggested that the content of li

关 键 词：火灾高温 轻骨料混凝土 抗压强度 劈裂抗拉强度 动态压缩性能 相对动弹性模量 

分 类 号：TU528.1[建筑科学—建筑技术科学]