Due to recycled aggregate concrete technology, sustainable resource utilization can be achieved, but the weak frost resistance of this type of concrete affects its application in cold regions. Using waste polypropylene fibers as reinforcing materials can improve the mechanical properties and durability of concrete. This study explores the influence of waste polypropylene fiber on the frost resistance durability and microstructure of recycled brick aggregate (RA) concrete. The results show that with the increase in freeze–thaw cycles, the mass of the concrete first increases and then decreases, while its relative dynamic elastic modulus and compressive strength gradually decrease. After 60 freeze–thaw cycles, the maximum mass loss, maximum relative dynamic elastic modulus loss, and maximum compressive strength loss of the RA concrete are 1.73, 45.1, and 73.7%, respectively. Waste fiber (WF) can improve the frost resistance of concrete, as demonstrated by the obvious reduction in mass loss, relative dynamic elasticity modulus loss, and compressive strength loss, which are 0.11, 33.0, and 64.0%, respectively, after 60 freeze–thaw cycles. The action mechanism of WF on the frost resistance of RA concrete is revealed, and the life prediction model of RA concrete with WF under freeze–thaw conditions is established.

中文翻译：

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废旧聚丙烯纤维再生砖骨料混凝土的抗冻性及寿命预测


由于再生骨料混凝土技术，可以实现资源的可持续利用，但该类混凝土的抗冻性能较弱，影响了其在寒冷地区的应用。使用废旧聚丙烯纤维作为增强材料可以提高混凝土的力学性能和耐久性。本研究探讨了废旧聚丙烯纤维对再生砖骨料（RA）混凝土抗冻耐久性和微观结构的影响。结果表明，随着冻融循环次数的增加，混凝土的质量先增大后减小，而相对动弹性模量和抗压强度逐渐减小。 60次冻融循环后，RA混凝土的最大质量损失、最大相对动弹性模量损失和最大抗压强度损失分别为1.73、45.1和73.7%。废纤维（WF）可以提高混凝土的抗冻性能，其质量损失、相对动弹性模量损失和抗压强度损失明显减少，经过60次冷冻后，分别为0.11、33.0和64.0%。解冻周期。揭示了WF对RA混凝土抗冻性的作用机理，建立了WF加入RA混凝土在冻融条件下的寿命预测模型。