低坍落度路面混凝土工作性评价指标研究  

Study on Evaluation Indicators for Workability of Low-slump Pavement Concrete

作　　者：权磊[1] 田波[1] 何哲[1] 屈允永 程谞 QUAN Lei;TIAN Bo;HE Zhe;QU Yun-yong;CHENG Xu(Research Institute of Highway,Ministry of Transport,Beijing 100088,China;School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]交通运输部公路科学研究院,北京100088 [2]重庆交通大学土木工程学院,重庆400074

出　　处：《公路交通科技》2020年第5期11-19,共9页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金青年基金项目(51608239);中央级公益性科研院所基本科研业务费专项资金项目(2018-9001);广西科技计划项目(桂科AC16380105);2019年度科技创新专项资金项目(2017-A30001)。

摘　　要：目前我国尚无成熟的试验方法和评价标准能够有效控制滑模施工用低坍落度混凝土的工作性。为了提升水泥混凝土路面滑模摊铺质量和平整度,从路面混凝土配制技术出发,基于自主开发的混凝土流变参数测定仪、出浆速度测定仪、立模特性测定装置等设备系统,研究了流变学参数和工作性经验指标对低坍落度混凝土工作性的敏感性,分析了流变学参数与工作性经验指标的相关性。研究结果表明:坍落度不能有效表征路面滑模施工用干硬性混凝土的真实性能状态;调整砂率能够显著改变新拌混凝土的屈服应力水平,调整含气量对屈服应力的影响则非常有限,砂率和含气量均能有效调节新拌混凝土的塑性黏度;存在最佳砂率和最佳含气量使得出浆速度最快。相关性分析表明:屈服应力水平能够显著影响混凝土表面粗糙度、塌边高度和振动黏度系数,而塑性黏度对4项经验指标均有显著影响;工程中宜将砂率控制在35%~45%,含气量控制在3%~5%,以获得与滑模施工工艺和高频振捣工艺匹配的最佳工作性能。基于多指标的低坍落度混凝土工作性调节机制在某高速公路水泥混凝土路面滑模施工中得到了验证,监测路段路面平整度平均值达到1.57 m/km,合格率达到90%。There is no mature test method and evaluation standard for effectively controlling the workability of low-slump concrete for slip-form machine construction in China at present. In order to improve the construction quality of cement concrete pavement paved by slip-form machine,in view of concrete proportion design, based the self-developed concrete rheometer, mortar overflowing rate test apparatus and edge slumping setup, etc., the sensitivity of rheological parameters and workability empirical indicators to the workability of low-slump concrete is studied, and the correlation of rheological parameters with workability evaluation indicators are analyzed. The result shows that(1) slump cannot effectively representative the real performance of the dry concrete adopted in pavement slip-forming;(2) adjusting sand ratio can change the yield stress of fresh concrete obviously, while the effect of adjusting air content on yield stress is very limited, both sand rate and air content can effectively adjust the plastic viscosity of fresh concrete;(3) there are the optimum sand ratio and the optimum air content making the mortar overflowing rate fast. The correlation analysis presents that(1)the yield stress level can significantly affect the concrete surface roughness, edge slumping and vibration viscosity coefficient, and plastic viscosity has remarkable effects on the 4 previous experience indicators;(2) it is suitable to confine the sand ratio in the range between 35% and 45% and the air content in the range between 3% and 5% to obtain the best workability performance matching with slip-form construction technique and high-frequency vibration technique. The multi-indicator based workability adjusting mechanism for low-slump concrete has been verified in the slip-form construction of the cement concrete pavement of an expressway. The average value of IRI reached 1.57 m/km and the qualified rate achieved 90% in the monitored section.

关 键 词：道路工程 工作性评价指标 相关性分析 低坍落度混凝土 流变特性 出浆速度 

分 类 号：U414[交通运输工程—道路与铁道工程]