玄武岩纤维对混凝土抗冻性能的影响

Effect of Basalt Fiber on Frost Resistance of Concrete

为研究玄武岩纤维掺量对混凝土抗冻性能的影响及作用机理,开展了快速冻融试验和微观孔隙试验,研究了4种不同玄武岩纤维体积掺量(0、0.1%、0.2%、0.3%)混凝土冻融循环过程中的外观、质量损失率、相对动弹性模量、抗压强度、抗折强度、冲击弹性波波速损失率及气泡特征参数的变化规律,并通过灰熵分析法对玄武岩纤维改善混凝土性能的微观机理进行了研究。结果表明:混凝土各项性能随着冻融循环次数的增加而逐渐降低;掺加玄武岩纤维能够提高混凝土抗冻性能且存在最优掺量;玄武岩纤维混凝土宏观性能的改变与气孔比表面积、含气量、弦长>200 nm气孔频率等微观孔隙参数之间呈一定的相关性;玄武岩纤维掺量为0.2%时对混凝土抗冻性能的改善效果最佳。

To investigate the influence and mechanism of basalt fiber content on the frost resistance of concrete,rapid freeze-thaw testes and microscopic pore testes are carried out to investigate the appearance,mass loss rate,relative dynamic elastic modulus,compressive strength,flexural strength,impact elastic wave velocity loss rate and bubble characteristic parameters of concrete with four different basalt fiber contents(0%,0.1%,0.2%,0.3%) during freeze-thaw cycles,and the microscopic mechanism of basalt fiber improving concrete performance is studied by grey entropy analysis.The results show that,(a) the properties of concrete gradually decrease with the increase of freeze-thaw cycles;(b) adding basalt fiber can improve the frost resistance of concrete and there is an optimal dosage;(c) the change of macroscopic properties of basalt fiber reinforced concrete is related to the change of microscopic pore parameters such as pore specific surface area,air content,and pore frequency with chord length > 200 nm;and(d) when the content of basalt fiber is 0.2%,the improvement effect of freezing resistance of concrete is the best.