含再生集料级配碎石的压实性能和强度试验研究

Experimental Study on Compaction Performance and Strength of Graded Crushed Gravel Containing Recycled Aggregates

与天然碎石的物理性质相比,再生混凝土集料(RCA)和再生粘土碎砖(RCB)表现出密度小、孔隙率大、吸水率高以及压碎值大的特点。在此基础上,采用再生集料部分替代天然碎石,按不同掺配比设计5种级配相同的级配碎石进行击实试验,试验结果表明:随着再生集料含量的增大,混合集料的最佳含水率增大,最大干密度减小。通过加州承载比(CBR)试验发现,再生集料的掺入有可能提高级配碎石的承载能力;含RCA的级配碎石可以用于各级公路的基层或底基层,其掺配比例可达到30%而不影响粒料的强度;为保证混合料CBR值满足现行规范的要求,RCB替代比例应控制在25%以内,并且只能用于二级及以下公路。

Compared with the physical properties of natural gravel,recycled concrete aggregate(RCA)and recycled clay brick(RCB)are characterized by low density,high porosity,high water absorption and high crushing value.On this basis,recycled aggregates are used to partially replace natural crushed stones,and five kinds of graded crushed stones with the same gradation are designed according to the different mixing ratio for compaction test.The test results show that with the increase in the recycled aggregate content,the optimum moisture content of mixed aggregate increases and the maximum dry density decreases.Through the California bearing ratio(CBR)test,it is found that recycled aggregates may improve the bearing capacity of graded macadam;that the graded macadam containing RCA can be used as the base or subbase of all levels of highways,whose mixing proportion can reach 30%without affecting the strength of the aggregates;that in order to ensure the CBR value of the mixture meets the requirements of the current specifications,the replacement ratio of RCB should be kept within 25%,and can only be used as the base or subbase of secondary highways and below.