Fuzzy synthesis method for evaluating quality class of recycled concrete coarse aggregate

Evaluating for quality of recycled concrete aggregates is crucial for appraising whether their performances accord with actural requirements from concrete structural engineering.A fuzzy synthesis method for evaluating quality class of recycled concrete coarse aggregate was proposed in this paper.Six indices,bulk specific density,water absorption,Los Angeles abrasion loss,attached mortar content,chlorid content and sulfate content were adopted to partition recycled concrete coarse aggregate quality into three fuzzy classes.And the three classes corresponded to excellent,eligible,and unqualified respectively.Farther,their practical environment action grades and corresponding engireenings were suggested.The CMFS method based on credibility matrix and frequency statistic was used to obtain indices weights,and optimum intervel membership function was chosen to decide the memberships of test indices.And synthetic membership score was considered as quality class judgment standard after judgment matrix was calculated by fuzzy weighted average operator.A computing program compiled in Matlab language was taken to calculate large numbers of engineering examples.Results show that the present evaluate method is objective and reliable.