郭佳栋1,郭荣鑫2,3,黄会明1
郭佳栋,郭荣鑫,黄会明.轻骨料混凝土高温力学性能劣化机理研究[J].混凝土与水泥制品,2022(12):24-27,45.
GUO J D,GUO R X,HUANG H M.Study on Deterioration Mechanism of Lightweight Aggregate Concrete at High Temperature[J].China Concrete and Cement Products,2022(12):24-27,45.
轻骨料混凝土高温力学性能劣化机理研究
郭佳栋1,郭荣鑫2,3,黄会明1
郭佳栋,郭荣鑫,黄会明.轻骨料混凝土高温力学性能劣化机理研究[J].混凝土与水泥制品,2022(12):24-27,45.
GUO J D,GUO R X,HUANG H M.Study on Deterioration Mechanism of Lightweight Aggregate Concrete at High Temperature[J].China Concrete and Cement Products,2022(12):24-27,45.
摘 要:测试了高温后轻骨料混凝土(LWC)的力学性能,探究了聚丙烯纤维掺量、高温温度(100、300、500、700、900 ℃)和冷却方式对LWC高温力学性能的影响,分析了LWC高温力学性能的劣化机理。结果表明:掺入适量的聚丙烯纤维可以提高LWC的残余抗压强度;在100~300 ℃和500~900 ℃区间温度时,各试件的烧失率增幅较大;经100 ℃高温后,喷水冷却的LWC残余抗压强度优于自然冷却的LWC,但经300 ℃高温后,相比于自然冷却,喷水冷却的LWC残余抗压强度降低幅度更大;自然冷却的LWC在300 ℃时出现较少裂缝,在500 ℃时裂缝快速发展;由于砂浆与骨料热膨胀系数的差异,喷水冷却使基体-骨料界面裂缝快速发展,LWC在300 ℃时便形成较多裂缝,故残余抗压强度降低幅度更大。
Abstract: The mechanical properties of the lightweight aggregate concrete(LWC) after high temperature were tested. The influences of polypropylene fiber content, high temperature(100、300、500、700、900 ℃) and cooling method on the high temperature mechanical properties of the LWC were explored, and its deterioration mechanism of high temperature mechanical properties was analyzed. The results show that adding proper amount of polypropylene fiber can improve the residual compressive strength of the LWC. At the range of 100~300 ℃ and 500~900 ℃, the loss on ignition rate of each specimen increases greatly. After being subjected to a high temperature of 100 ℃, the residual compressive strength of the LWC cooled by water spray is better than that of the natural cooling, but after 300°C, the residual compressive strength of the LWC cooled by the water spray has a greater decrease in strength compared to the natural cooling. For the naturally cooled LWC, the cracks are formed after a high temperature of 300 ℃, and the cracks develop rapidly after a high temperature of 500 ℃. Due to the difference in thermal expansion coefficient between mortar and aggregate, rapid cooling causes rapid development of mortar-aggregate interface cracks. Therefore, for the LWC cooled by water spray, the formation of large cracks can accelerate at 300 ℃, so the residual compressive strength decreases faster.
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