冻融循环下混杂纤维再生混凝土抗压强度预测方法

为了研究冻融循环对混杂纤维再生混凝土受压性能的影响,本文进行了钢纤维和聚丙烯纤维再生混凝土的冻融试验,并通过单轴压缩试验研究了冻融循环次数和纤维掺量对再生混凝土抗压强度的影响规律。试验结果表明,冻融次数的增加会导致再生混凝土抗压强度和弹性模量逐渐降低,加入纤维可以改善其受压性能。基于含夹杂弹性体内部应变场积分方程,推导了多相复合材料夹杂的变形协调张量,得到了预测混杂纤维再生混凝土弹性性能的修正Mori-Tanaka方法,建立了耦合冻融损伤和受力损伤的总损伤表达式,进而提出冻融循环作用下混杂纤维再生混凝土抗压强度预测方法。采用本文提出的抗压强度预测方法对冻融循环作用下的纤维再生混凝土受压性能进行了预测,并将预测结果与本文试验值进行对比,结果表明预测结果和试验值吻合较好,拟合优度达到98%以上。因此,本文提出的抗压强度预测方法可为混杂纤维再生混凝土在冻融循环条件下的工程应用提供一定的理论依据。

Compressive strength prediction method for hybrid fiber recycled concrete under freeze-thaw cycles

In order to study the effect of freeze-thaw cycles on the compressive properties of hybrid fiber recycled concrete, freeze-thaw tests on steel fiber and polypropylene fiber recycled concrete were conducted in this paper, and the effect of the number of freeze-thaw cycles and fiber admixture on the compressive strength of recycled concrete was studied by uniaxial compression tests. The test results show that the increase of the number of freeze-thaw cycles leads to a gradual decrease of the compressive strength of the recycled concrete, and the addition of fibers can improve its compressive properties. The modified Mori-Tanaka method for predicting the elastic properties of recycled concrete with hybrid fibers was obtained based on the integral equation of the internal strain field of the elastomer containing the inclusions, the deformation coordination tensor of the multi-phase composite inclusions was derived, the total damage expression of coupled freeze-thaw damage and force damage was established, and then the method for predicting the compressive strength of recycled concrete with mixed fibers under the action of freeze-thaw cycles was proposed. The compressive strength prediction method proposed in this paper was used to predict the compressive properties of fiber-recycled concrete under the action of freeze-thaw cycles, and the predicted results were compared with the experimental values in this paper, and the results showed that the predicted results and the experimental values were in good agreement, and the goodness of fit reached more than 98%. Therefore, the compressive strength prediction method proposed in this paper can provide some theoretical basis for the engineering application of hybrid fiber recycled concrete under freeze-thaw cycles.