Evaluation of recycled aggregate based on analysis hierarchy process-grey variable weight clustering

In order to overcome the errors caused by the subjective and random factors in the evaluation of the quality of recycled coarse aggregate (RA), and to ensure that a scientific and reasonable choice is made for its application field. In this paper, seven parameters of apparent density, porosity, soundness, crushing index, content of fine powder, content of clay lump and water absorption rate were used as comprehensive evaluation indicator of the quality grade of RA. The quality grade of RA was divided into four grades of disqualified, qualified, good and high quality. Analysis hierarchy process-gray variable weight clustering method was used for evaluation. The evaluation was divided into three steps, including: 1) weight calculation of the seven parameters by the method of analysis hierarchy process (AHP); 2) hierarchical classification by the method of grey variable weight clustering (GC); and 3) establishment of a quality evaluation method for RA. Then the scientificity of the evaluation method was tested with examples. The calculation results show that the evaluation method can provide theoretical support for the research on the quality grade of RA and has certain guiding significance.