冻融循环作用下水泥稳定碎石抗冻特性

发布时间：2018-04-05 14:13

本文选题：道路工程　切入点：水泥稳定碎石　出处：《长安大学学报(自然科学版)》2017年04期

【摘要】：针对水泥稳定碎石(简称水稳碎石)等半刚性基层在青藏高原高海拔地区频繁冻融循环作用下,易造成材料强度与耐久性下降,影响路面整体使用性能问题。以拉萨—贡嘎机场专用公路新建工程为依托,从水稳碎石的抗冻融性能出发,采用室内试验模拟冻融循环过程,分析水稳碎石经不同次冻融循环作用后的强度损失规律,引入抗压强度耐冻系数与劈裂强度耐冻系数作为抗冻融性能评价指标,对比分析水泥用量、养生温度和冻融循环次数与水稳碎石耐冻系数的相关性;以水稳碎石耐冻系数为主参数,水泥用量、养生温度与冻融循环次数为变量,引入温度修正系数对基层养生温度影响进行修正,并对耐冻系数进行回归,建立二元线性预测模型,计算模型计算值与试验实测值的相对误差,验证模型的拟合精度。研究结果表明:水稳碎石的强度与耐冻系数随冻融循环次数的增加而降低,强度在0~5次冻融循环周期内下降较为明显;较高的水泥用量与养生温度可有效降低水稳碎石冻融后的强度损失,建议工程中控制水泥用量为4%(质量分数,下同),同时保证养生温度大于10℃可有效提高材料抗冻融性能;所建二元线性预测模型具有较高的拟合精度和很好的再现性,可为水稳碎石抗冻融性能研究提供参考,为特殊地区半刚性基层设计施工提供技术指导。
[Abstract]:Under the action of frequent freeze-thaw cycles in high altitude area of Qinghai-Tibet Plateau, the semi-rigid base such as cement stabilized crushed stone (hereinafter referred to as water-stabilized crushed stone) will easily cause the decrease of material strength and durability, which will affect the overall performance of pavement.Based on the new highway construction project of Lhasa Gongga Airport, based on the freeze-thaw resistance of water-stabilized crushed stone, the laboratory test is used to simulate the freeze-thaw cycle process, and the strength loss law of water-stabilized crushed stone after different freeze-thaw cycles is analyzed.The freezing resistance coefficient of compressive strength and splitting strength were introduced as the evaluation index of freeze-thaw resistance. The correlation of cement dosage, curing temperature and freeze-thaw cycle times with freezing resistance coefficient of water-stabilized crushed stone was compared and analyzed.Taking the freezing resistance coefficient of water stabilized macadam as the main parameter, cement dosage, curing temperature and freeze-thaw cycle times as variables, the influence of temperature correction coefficient on the basic health preservation temperature was revised, and the freezing resistance coefficient was regressed.A binary linear prediction model is established to calculate the relative error between the calculated value and the experimental value, and to verify the fitting accuracy of the model.The results show that the strength and the coefficient of frost resistance of water-stabilized crushed stone decrease with the increase of freeze-thaw cycle times, and the strength decreases more obviously in the period of 0 ~ 5 cycles of freeze-thaw cycle.High cement content and health temperature can effectively reduce the strength loss after freezing and thawing of water-stabilized macadam. It is suggested that the control of cement dosage of 4 (mass fraction, the same as the following) in engineering can effectively improve the freeze-thaw resistance of the material.The binary linear prediction model has high fitting accuracy and good reproducibility. It can be used as a reference for the study of the freeze-thaw resistance of water-stabilized crushed stone and a technical guide for the design and construction of semi-rigid base in special area.
【作者单位】：长安大学特殊地区公路工程教育部重点实验室;沈阳公路路政管理局;
【基金】：“十二五”国家科技支撑计划项目(2014BAG05B04) 交通运输部建设科技项目(2013 318 490 010) 中央高校基本科研业务费专项资金项目(310821161015)
【分类号】：U416.214

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