Quality assessment for recycling aggregates from construction and demolition waste: The determination of the particle size distribution by an image analysis approach

The particle size distribution of aggregates has direct and important effects on fundamental properties of construction materials such as workability, porosity, strength and duration. Assessing the size distribution of aggregates from construction and demolition waste (CDW) is therefore of primary importance to determine the degree of recyclability of such materials. Unfortunately, standard methods like sieving or laser diffraction can be either very time consuming (sieving) or possible only in laboratory conditions (laser diffraction). As an alternative we propose and evaluate the use of image analysis to estimate the size distribution of aggregates from CDW in a fast yet accurate manner. The effectiveness of the procedure was tested on aggregates generated by an existing waste mechanical treatment plant. Experimental comparison with manual sieving showed agreement in the range 81% – 85%. The proposed technique demonstrated potential for being used as on-line system exploitable directly in CDW mechanical treatment facilities.