掺聚合物纤维面板混凝土的防裂抗冻性能

Effect of Polymer Fiber on Frost and Crack Resistance of Face Concrete

严寒区面板混凝土的抗裂防冻性能对大坝的耐久性具有较大影响,本文采用平板法研究了不同聚丙烯腈纤维掺量对掺粉煤灰面板混凝土的早期抗裂性;采用冻融试验、气泡参数试验方法研究了掺聚丙烯腈纤维面板混凝土的质量损失、相对动弹性模量变化、气泡参数变化特征。研究结果表明:细短型聚丙烯腈纤维在面板混凝土内分布的平均间距约为5.98 mm,聚丙烯腈纤维的增强阻裂效果提高了面板混凝土的强度和早期抗裂性;掺入聚丙烯腈纤维后,面板混凝土的引气效果更好,且引入气泡的间距系数小于200μm,聚丙烯腈纤维弹性模量随温度降低而增大的特点,可以提高面板混凝土的抗冻性能。

The anti crack and anti freezing performance of face concrete in cold area has great influence on the durability of dam. The early crack resistance of face concrete was studied by plate method, and the frost resistance and bubble parameter were also studied by freezing-thawing test and bubble test respectively. The test results show that the average distance between the thin and short type PAN fiber in the face concrete is 5.98 mm, and PAN fiber can improve the early crack resistance of face concrete. After incorporation of PAN fiber, the air entraining effect of concrete is better, and the bubble spacing coefficient in face concrete is less than 200 μm. The elastic modulus characteristic of PAN fiber can improve the frost resistance of face concrete.