淮北水洗煤矸石的基层应用可行性研究

Feasibility Research of Huaibei Washing Gangue Using in Base Course

为研究通过水泥稳定将淮北水洗煤矸石应用于公路路面基层的可行性,避免原材料中有害成分的影响,首先检测了煤矸石的成分,然后通过电镜观测了其通过水泥稳定后的状态。为满足路面基层混合料的指标要求,通过击实试验确定了试件的最佳含水率,测试了按不同剂量直接掺入水泥稳定时试件的7d无侧限抗压强度,结果发现该指标偏低。为此,参照规范中普通水泥稳定碎石级配,按照用水洗煤矸石替代4.75~9.5mm普通集料的思路,设计了多种级配,并制备试件,对比测试了其7d无侧限抗压强度。试验结果表明,适宜的质量比例为:1#料25%~30%,煤矸石(替代3#料)43%~47%,4#料16%~18%,最后确定2#料的用量。按照此原则设计混合料级配,当水泥剂量为5.5%时,试件的7d无侧限抗压强度均值可大于5.0MPa,满足各类公路路面基层与底基层的需要,从而验证了淮北水洗煤矸石替代集料应用于公路路面基层的可行性。

For studying the feasibility of applying Huaibei washing coal gangue to the base layer of highway pavement through cement stabilization,and avoiding the influence of harmful components in raw materials,the compositions were tested firstly,and then the state of the material was observed by electron microscope.In order to meet the requirements of the pavement base mixture,the optimum moisture content was determined by the compaction test,and the 7 d unconfined compressive strength when the cement was mixed directly at different doses was tested.It was found that the target was on the low side.So,with reference to the ordinary cement stabilized macadam grading in the specification,according to the idea of replacing the 4.75~9.5 mm common aggregate with coal gangue,a variety of gradations were designed,and the specimens were compared.The test results show that,the suitable mass ratio of 1#material is 25%~30%,coal gangue(replaces 3#material)is 43%~47%,4#material is 16%~18%,and 2#material is determined finally.According to this principle,when the cement dosage is 5.5%,the average value of the 7 d unconfined compressive strength can be greater than 5.0 MPa,which satisfies the needs of various road pavement base courses.The feasibility of using Huaibei washing coal gangue to replace aggregates for road pavement base course was verified.