引气粉煤灰道面混凝土抗冻融性能试验研究

采用快速冻融法,测定了不同冻融循环次数下引气粉煤灰混凝土试件的质量损失、相对动弹模量和抗弯拉强度。研究了水胶比、引气剂掺量和粉煤灰掺量对混凝土抗冻性能的影响规律。结果表明:提高水胶比会增大水泥石内部孔径和孔隙率,混凝土更容易遭受冻融破坏;掺加粉煤灰不利于提高混凝土抗冻耐久性,随着粉煤灰掺量的增加,混凝土冻融循环后力学性能呈下降趋势;引气剂能够改善混凝土拌和物的泌水和离析现象,减小混凝土循环冻融后抗弯拉强度的损失。

Research on the freeze-thaw durability of Air-entraining Fly-Ash concrete

With accelerated freezing and thawing tests, the influence of water-binder ratio, air entraining agent and fly ash content on Air-entraining Fly-Ash concrete were investigated. Results show that higher level of water-binder ratio increases air void size and porosity, making the Air-entraining Fly-Ash concrete vulnerable to freeze-thaw damage. Fly ash presents adverse effects on frost durability of concrete. With increase of fly ash content, the mechanical properties of concrete show the downtrend. Air entraining agent can improve the concrete bleeding and segregation, and reduce the loss of flexural tensile strength after freeze-thaw cycles.