摘要
针对不预湿、搅拌前、搅拌过程中预湿再生粗骨料等不同搅拌工艺对再生骨料混凝土(RAC)工作性能的影响问题,采用正交试验方法,研究了适用于市政道路次干路路面要求的配合比及RAC的抗冻性能。结果表明:1)在搅拌前预湿再生粗骨料制备的RAC的1 h坍落度比搅拌过程中预湿大40 mm,搅拌前预湿能更好地提高RAC工作性能;2)RAC抗折强度的影响因素依照显著性依次为再生骨料取代率、水灰比和砂率;3)随着冻融循环次数的增加,RAC相对动弹性模量逐渐减小,最小为68.97%,而RAC质量先增加后减小,且再生骨料取代率越高,RAC的冻融损伤程度越大,质量损失率最大为1.747%;4)同时考虑再生粗骨料取代率和冻融循环次数2个因素,建立冻融循环后RAC寿命预测模型,计算结果显示,预测抗冻寿命约为22.7年,满足市政道路次干路标准。研究结果可供RAC在市政道路中的应用参考。
Regarding the influence of different mixing processes,such as non-pre-wetting,pre-wetting of recycled coarse aggregates before mixing,and pre-wetting during mixing,on the workability of recycled aggregate concrete(RAC),an orthogonal test method was adopted to study the mix proportion suitable for the pavement requirements of municipal secondary roads and the frost resistance of RAC.The results indicated that:1)The 1h slump of RAC prepared by pre-wetting recycled coarse aggregates before mixing is 40 mm larger than that pre-wetted during mixing,indicating that pre-wetting before mixing can better improve the workability of RAC;2)The influencing factors on the flexural strength of RAC are ranked by significance as recycled aggregate replacement rate,water-cement ratio,and sand ratio;3)With the increase of freeze-thaw cycles,the relative dynamic elastic modulus of RAC gradually decreases,with the minimum value being 68.97%,while the mass of RAC first increases and then decreases.Moreover,the higher the recycled aggregate replacement rate,the greater the freeze-thaw damage degree of RAC,with the maximum mass loss rate being 1.747%;4)Considering the replacement rate of recycled coarse aggregate and the number of freeze-thaw cycles,a RAC life prediction model was established after freezethaw cycles.The calculation results showed that the predicted frost resistance life was about 22.7 years,which meets the standards of municipal road sub dry roads.The relevant results of this article can provide reference for the application of RAC in municipal roads.
作者
周再恒
邢培营
彭俊
汪仕发
ZHOU Zaiheng;XING Peiying;PENG Jun;WANG Shifa(Guangdong Provincial Highway Construction Co.,Ltd.,Guangzhou 510623)
出处
《公路交通技术》
2025年第3期37-46,共10页
Technology of Highway and Transport
基金
新疆维吾尔自治区重点研发任务专项项目(2022B03036-3)
新疆维吾尔自治区自然基金重点项目(2022D01D27)。
