受冻融影响的纤维陶粒混凝土高温后力学性能试验研究

Experiment study on the mechanical performance of fiber ceramisite concrete subjected to freeze-thaw after elevated temperature

试验首先对无纤维、塑钢纤维（HPPF）和聚丙烯腈纤维（PANF）三组陶粒混凝土进行冻融循环作用,然后分20,200,400,600,800℃五个温度水平进行高温作用,研究受冻融影响高温作用下,未掺纤维和掺入不同纤维的陶粒混凝土力学性能变化规律。试验结果表明：纤维的掺入能够对陶粒混凝土中裂缝的产生和扩展起到一定阻止作用,使陶粒混凝土的抗冻性能得到改善,有效缓解混凝土脆性破坏特征;未经冻融作用时,掺入HPPF,PANF后,在20~400℃范围内,陶粒混凝土的立方体残余抗压强度均高于无纤维掺入的陶粒混凝土,在20~200℃范围内,可明显地提高陶粒混凝土的残余劈裂抗拉强度;冻融循环作用后,无纤维陶粒混凝土的残余抗压强度和残余劈裂抗拉强度都明显高于其他二者;冻融循环作用后,在20~400℃三组陶粒混凝土的棱柱体残余抗压强度值明显减小。

To study the variation of mechanical performance of different fiber ceramisite concrete after freeze-thaw cycle and high temperature,tests were conducted on three groups of specimens under five temperature levels（ 200℃,400℃,600℃and 800℃）. The three groups are ceramisite concrete without fiber, with plastic steel fiber（ HPPF） and with polyacrylonitrile fiber（ PANF）. The results indicates that the incorporation of fibers can prevent the generation and expansion of cracks in ceramsite concrete, and it could improve frost resistance and alleviate the brittle fracture characteristics effectively. Before the freeze-thaw effect,the cubic residual compressive strength of ceramsite concrete was improved by the incorporation of fibers in the range of temperature from 20℃ to 400℃ and the residual splitting tensile strength was improved in the range of temperature from 20℃ to 200℃. After the freeze-thaw cycle effect,the residual compressive strength and residual tensile strength of fiber-free ceramsite concrete are significantly higher than the other two.After the freeze-thaw cycle effect,the prismatic residual compressive strength values of the three groups of ceramsite concrete at temperature from 20℃ to 400℃ were significantly reduced.