. Significance of the Research
Based on the results of the studies reported before and on investigations performed by the authors, it appeared that the determinationoftheRMCinRCAwasofcriticalimportanceto better understand / evaluate the properties of concrete incorporating RCA. However, there is currently no standard method for the determination of the RMC in RCA. In fact, different techniques have been used and reported by some authors for such measurements:
• Nagataki et al. [10] used hydrochloric acid dissolution; the authors applied a correction factor to account for partial dissolution of the original coarse aggregate (carbonate aggregate - limestone). • Sri Ravindrarajah and Tam [18] manufactured concrete cubes using RCA and a white cement binder; they then determined the attached mortar content in the RCA on traverses through four slabs sliced from the cubes, using an electronic digital planimeter. • Sanchez de Juan and Gutierrez [7] reported a method where theRCAaresubjectedtoheattreatment,soakingoftheRCA in water (prior and after heat treatment), and manual removal (rubber hammering and scratching) of the RMC.
Based on extensive laboratory investigations, which were part of a comprehensive research program whose ultimate objective is to establish the specifications and guidelines for routinelyproducingstructural-gradeconcretemadewithRCA, Abbas et al. [19,20] developed a quick laboratory test method for determining the RMC of RCA using different size fractions ofRCAfromtwocommercialsourcesinCanada.Theobjective of such a test is to allow the quick determination of RMC for quality control purposes of RCA. In order to validate the results obtained through the above laboratory test method, image analysis was performed on
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