玄武岩纤维再生混凝土抗冻性能及损伤劣化模型

FROST RESISTANCE AND DAMAGE DEGRADATION MODEL OF BASALT FIBER REGENERATED CONCRETE

为了研究纤维再生混凝土的抗冻性能,提高寒区再生混凝土结构服役寿命,试验采用等体积再生骨料替代石子制备了5组不同玄武岩纤维掺量的再生混凝土,分别从质量损失率、相对动弹性模量、抗压强度和抗拉强度等方面探讨纤维再生混凝土抗冻性能损伤劣化规律。研究结果表明:冻融初期,再生混凝土质量损失率呈现负增长现象,相对动弹性模量、抗压强度和抗拉强度曲线随冻融循环次数的增加呈下降趋势;玄武岩纤维加入能够减缓再生混凝土冻融破坏,掺量为1.2 kg·m^(-3)时再生混凝土的抗冻性能最优;纤维加入对冻融作用下再生混凝土抗拉强度的作用效果优于抗压强度。建立了基于相对动弹性模量和强度为损伤变量的线性及多项式损伤劣化模型,模型可以准确预测纤维再生混凝土冻融损伤劣化程度。

In order to study the frost resistance of fiber recycled concrete, improve the service life of recycled concrete structures in cold areas. Five groups of recycled concrete with different basalt fiber content were prepared by using equal volume recycled aggregate instead of gravel. The damage deterioration law of frost resistance of recycled concrete with fiber was discussed from the aspects of mass loss rate, relative dynamic elastic modulus, compressive strength and tensile strength. The research results show that: At the beginning of freezing and thawing, the mass loss rate of recycled concrete exhibits a negative growth phenomenon, and the relative dynamic elastic modulus, compressive strength and tensile strength curves show a downward trend with the increase of the number of freezing and thawing cycles;the addition of basalt fiber can slow down the freezing of recycled concrete. When thawing failure, the frost resistance of recycled concrete is the best when the dosage is 1.2 kg·m-3;the effect of fiber addition on the tensile strength of recycled concrete under freeze-thaw action is better than compressive strength. A linear and polynomial damage degradation model based on relative dynamic elastic modulus and strength as damage variables is established. The model can accurately predict the degree of freeze-thaw damage and degradation of fiber recycled concrete.