不同亲水性能的纤维对混凝土抗冻耐久性的影响

中文摘要: 为了研究不同亲水性能的纤维对混凝土抗冻性能的影响规律，选择3种不同回潮率的纤维，采用快冻法对纤维混凝土的抗冻耐久性进行试验研究；分析不同纤维混凝土的冻融损伤规律，以及回潮率对其冻融损伤的影响。利用SEM对冻融前后纤维-水泥石基体进行了观测，进一步探讨纤维亲水性对混凝土抗冻性能的影响机理。结果表明，亲水性良好的纤维能够与水泥石更好的共同作用，有效抑制混凝土内部初期微缺陷及冻融过程中微缺陷的生长；而疏水性纤维难以与水泥石难以形成有效的共同作用体系，对于冻融循环过程中微缺陷的生长抑制能力较弱，其纤维-水泥石之间的薄弱带甚至可能会加速混凝土的冻融损伤；且随着冻融循环次数的增加，纤维的亲水性对混凝土的抗冻性能影响愈加明显。
Abstract:Three kinds of fibers with different rate of moisture regain were selected to study the effect of hydrophilism of fibers on the durability of fiber reinforced concrete during freeze-thaw with the rapid freeze-thaw cycle experiment.Microstructure of fiber-cement matrix were observed using SEM before and after freeze-thaw.The results showed that compared with the hydrophobic fibers,since the latter can be tightly bonded with cement matrix together hydrophilic fibers can effectively inhibit the initial micro-defects of concrete and prevent the growth of micro-defects in the freeze-thaw cycles.Therefore,hydrophobic fiber concrete may even accelerate the growth of damage during freeze-thaw cycles,due to the interfacial performance between fibers and concrete is weak.With the increase of freeze-thaw cycles,the impact on frost resistance of concrete by the hydrophilic of fibers became more and more obvious.