聚丙烯纤维对高寒地区水稳基层冷再生混合料性能的影响

Effect of polypropylene fiber on properties of cold recycled mixture of water stabilized base course in alpine region

为了改善高寒地区水泥稳定冷再生混合料的抗冻和抗干缩性能,提高水泥稳定冷再生技术在市政道路中的应用效果。研究了聚丙烯纤维对水泥稳定冷再生混合料的低温抗冻性、抗干缩开裂能力、抗拉和抗压强度性能的影响。聚丙烯纤维在水泥稳定碎石中起到加筋作用,增强了水泥稳定冷再生混合料的强度、韧性和抗裂性。综合分析得出在标准养护条件下,振动成型法成型的水泥稳定再生混合料的聚丙烯纤维最佳掺量为0.9 kg/m3,最佳纤维长度为12 mm。结合包头等高寒地区全年的气候情况,设计了具有代表性的不同养护条件,研究高寒地区环境对聚丙烯纤维水泥稳定冷再生混合料性能的影响。聚丙烯纤维水泥稳定冷再生混合料在恶劣养护条件下仍能保持较高的力学性能,在确保混合料抗压强度、抗拉强度、抗冻性满足规范要求的情况下,聚丙烯纤维的加入可以减少0.5%的水泥用量。聚丙烯纤维水泥稳定冷再生混合料有效地解决了高寒地区低温、低湿度和昼夜温差大导致水泥稳定冷再生基层易发生的强度不足和开裂等病害,延长了冬季可施工时间。

In order to improve the frost resistance and dry shrinkage resistance of cement stabilized cold recycling mixture in alpine region,and improve the application of cement stable cold recycling technology in municipal roads,the low temperature frost resistance,dry shrinkage cracking resistance,tensile and compressive strength properties of polypropylene fiber for cement stabilized cold recycled mixture were studied.It is concluded that polypropylene fiber plays a reinforcing role in cement stabilized macadam.This improves the strength,toughness and crack resistance of the cement stabilized concrete matrix.Comprehensive analysis shows that under the standard curing conditions,the optimal content of polypropylene fiber in cement stabilized recycled mixture formed by vibration molding method is 0.9 kg/m3,and the optimal fiber length is 12 mm.Combined with the annual climate of Baotou and other alpine regions,the representative different curing conditions were designed to study the influence of high cold area on the performance of polypropylene fiber cement stabilized cold recycled mixture.It is concluded that the addition of polypropylene fiber can reduce 0.5%of the cement consumption and the polypropylene fiber cement can stabilize the cold recycling performance when the compressive strength,tensile strength and frost resistance of the mixture are ensured.The problems of insufficient strength and cracking of cement stabilized cold recycled base which are resulted from low temperature,low humidity and large temperature difference between day and night in high and cold regions are solved.The construction time in winter is prolonged.