盐冻循环作用下水泥稳定碎石混合料的宏细观性能  

Macro and Micro Properties of Cement Stabilized Crushed Stone Mixture Under Salt Frost Coupling Erosion

作　　者：王宏[1] 李刚[1] WANG Hong;LI Gang(CCCC First Highway Consultants Co.,Ltd.,Xi’an,Shaanxi 710068,China)

机构地区：[1]中交第一公路勘察设计研究院有限公司,陕西西安710068

出　　处：《公路交通科技》2024年第10期90-102,共13页Journal of Highway and Transportation Research and Development

基　　金：2022年度交通运输行业重点科技项目(2022-MS1-073)。

摘　　要：为研究盐分和冻融循环耦合侵蚀作用下水泥稳定碎石混合料的力学性能、疲劳特性及微细观空隙结构衰减规律,在冻融条件下对不同初始含盐量的水泥稳定碎石混合料开展无侧限抗压强度试验、弯拉强度试验、动态压缩模量试验和三分点加载疲劳试验。基于工业CT无损检测技术研究了盐冻耦合作用下水泥稳定碎石混合料微细观空隙结构衰减规律;提出了盐冻循环次数与盐溶液浓度对水泥稳定碎石混合料力学性能、疲劳性能和微细观空隙直径期望值的衰减公式;建立了微细观空隙结构与宏观力学性能、疲劳性能之间的拟合关系。结果表明:盐冻耦合侵蚀作用加速了水泥稳定碎石混合料力学性能与疲劳特性衰减,随着盐冻循环次数增加,水泥稳定碎石混合料的无侧限抗压强度与动态回弹模量呈指数模型衰减,弯拉强度与疲劳寿命呈三次函数模型衰减;盐冻损伤主要集中在集料边缘的原生空隙部位,微细观等效空隙直径期望值和空隙级配中小于0.1 mm3的空隙数量随着盐冻耦合侵蚀作用次数增加而增大;硫酸钠盐溶液浓度越大,经历相同盐冻循环后水泥稳定碎石混合料力学性能和疲劳性能损伤度越高,微细观等效空隙直径期望值随着硫酸钠盐溶液浓度增大呈线性关系增大;随着等效空隙直径期望值增大,水泥稳定碎石混合料的动态回弹模量、无侧限抗压强度和弯拉强度均呈线性关系减小,同时疲劳寿命呈指数函数关系降低;盐冻耦合侵蚀作用改变了水泥稳定碎石内部微细观空隙结构,是盐冻耦合侵蚀作用导致水泥稳定碎石混合料力学性能和疲劳性能下降的原因之一。To study the mechanical properties,fatigue characteristics and micro void structure attenuation law of cement stabilized crushed stone mixture under the coupling erosion of salt solution and freeze-thaw,the unconfined compressive strength test,flexural tensile strength test,dynamic compression modulus test and three-point loading fatigue test were carried out on cement stabilized crushed stone mixture with different initial salt contents under freeze-thaw conditions.Based on the industrial CT non-destructive testing technology,the attenuation law of micro void structure of cement stabilized crushed stone mixture under salt frost coupling was studied.The decay formula for calculating the coupling effects of salt frost cycles and concentration of salt solution on the mechanical properties,fatigue properties and the expected value of micro void diameter of cement stabilized crushed stone mixture was proposed.The relation among micro and micro void structure and macro-mechanical and fatigue properties was established.The result indicates that the salt frost coupling erosion accelerates the attenuation of mechanical properties and fatigue characteristics of cement stabilized crushed stone mixture.With the increase of salt frost cycles,the unconfined compressive strength and dynamic resilience modulus of cement stabilized crushed stone mixture decay exponentially.The bending tensile strength and fatigue life decay in the cubic function model.The salt frost damages mainly concentrate in the primary void at the edge of aggregate.The expected equivalent pore diameter and the number of pores less than 0.1 mm 3 in the pore gradation increase with the increase of the number of salt frost coupling erosion.The higher the concentration of sodium sulfate solution,the higher the damage degree of mechanical properties and fatigue properties of cement stabilized crushed stone mixture after the same salt frost cycles.The expected value of micro equivalent void diameter increases linearly with the increase of sodium sulfate solution

关 键 词：道路工程 力学性能 无侧限抗压强度试验 水泥稳定碎石混合料 盐冻耦合侵蚀作用 疲劳特性 微细观空隙结构 衰减规律 

分 类 号：U416.2[交通运输工程—道路与铁道工程]