废旧混凝土用作水泥稳定基层的实验研究

随着城市建设的发展,城市道路改建时产生的大量的废弃混凝土块的有效利用成了一个亟待解决的问题。结合宜昌市东山大道改建项目,将废弃的混凝土面板加工形成再生集料用作水泥稳定碎石基层,达到节约资源和保护环境的目的。实验分析了再生集料的颗粒级配、压碎值、针片状颗粒含量、表观密度和吸水率等工程性质指标,同时对水泥稳定再生碎石的级配、最佳水泥掺量进行了设计,并对水泥稳定再生碎石的无侧限抗压强度指标进行了研究。研究表明,废旧混凝土经加工形成的再生集料具有良好的路用性能,其颗粒级配、压碎值以及主要指标均达到了路面基层材料的要求;掺3%、5%和7%水泥稳定再生集料7 d浸水抗压强度均达到路面基层的要求,水泥稳定再生集料用作路面基层是可行的;掺3%水泥稳定的再生集料可以用在公路的底基层,掺5%及7%水泥稳定的再生集料可以分别用作路面下基层和上基层。

Experimental study on waste concrete used as cement stabilized base

With the rapid development of urban construction, how to effectively utilize the large amounts of discarded concrete blocks produced by urban road reconstruction has become an urgent issue. In the project of Dongshan Avenue reconstruction in Yichang City, the discarded concrete blocks slabs were transformed into recycled aggregate as cement to stabilize the macadam base for the purpose of both resource conservation and environmental protection. The engineering properties of indicators for the recycled aggregate including grain composition, crushing value, content of needle flat, apparent density and water absorption were analyzed by a series of experiments. The optimized cement doping, gravel grading and unconfined compressive strength parameter of the cement stabilized recycled gravel were discussed and researched. The results show that the recycled aggregate made by the discarded concrete has good pavement performance with the main parameters such as grain composition and crushing value meeting the standards of pavement base materials. The compressive strength of recycled aggregate stabilized by 3%, 5% and 7% cement after 7 days of immersion can meet the requirements of pavement base; therefore, the recycled aggregate stabilized by cement is feasible to be used as pavement base. The recycled aggregate stabilized by 3%, 5% and 7% cement can be utilized as highway subbase layer, bottom and top pavement base, respectively.