超高性能混凝土与普通混凝土的黏结抗冻性能

对147个超高性能混凝土与普通混凝土的100mm×100mm×100mm立方体黏结试件进行了冻融循环后的黏结性能研究,测量了冻融后试件的相对动弹性模量、质量损失率以及劈裂抗拉强度,研究了超高性能混凝土中的钢纤维掺量、普通混凝土的强度等级、黏结面形式、试件的浇筑方向等因素对黏结试件抗冻性能的影响。结果表明,冻融循环结束后,所有黏结试件中的超高性能混凝土部分都没有出现损伤,超高性能混凝土可以作为普通混凝土结构的理想外围护材料;随着冻融循环次数的增加,黏结试件的相对动弹性模量逐渐减小,质量损失率先降低后增加,黏结试件的劈裂抗拉强度线性下降;影响黏结试件冻融后劈裂抗拉强度下降速度的关键因素是超高性能混凝土中的钢纤维掺量和黏结面的形式。

Bonding Performances of Ultra High Performance Concrete to Normal Concrete Under Freeze-Thaw Cycle

147 ultra high performance concrete-normal concrete bonded cubes with dimension of 100 mm × 100 mm × 100 mm were tested to investigate the bonding performance under freeze-thaw cycle test. The relative dynamic elastic modulus, mass loss rate and splitting tensile strength of specimens were measured after freeze-thaw cycle. The effects of steel fibers in ultra high performance concrete, the strength of normal concrete, the form of bonding surface and the casting direction of concrete on the freeze-thaw resistance of bonded specimens were studied. The results show that the ultra high performance concretes in all bonded specimens remain undamaged after the freeze-thaw cycle, and the ultra high performance concrete can be applied as an ideal external enclosure material for normal concrete structures. With the increase of the freeze-thaw cycles, the relative dynamic elastic modulus of specimens are decreased gradually, the mass loss rates are decreased first and then increased, and the splitting tensile strengths are decreased linearly. The key factors that affect the rate of strength decline of the bonded specimens under freeze-thaw cycle are the contents of steel fiber in ultra high performance concrete and the form of bonding surface.