PARTICLE-SIZE DISTRIBUTION ANALYSIS OF COARSE AGGREGATE USING DIGITALIMAGE-PROCESSING

An attempt at applying the digital image processing (DIP) technique to analyze the particle size distribution of coarse aggregate is made. T hree different types of aggregates have been analyzed, and their gradi ng curves are compared to those obtained by conventional mechanical si eving. Because DIP produces only area gradation and uses a particle si ze definition different from the square sieve size used in mechanical sieving, direct comparison is not possible unless the gradation basis and particle size definitions of the two methods are aligned. For this purpose, a simple method of converting the area gradation to mass gra dation is proposed. Moreover, a size correction factor is used to conv ert the particle sizes measured by DIP to equivalent square sieve size s so that comparison between the DIP and mechanical sieving results ca n be made. The study demonstrates that DIP is a fast, convenient, vers atile, and accurate technique for particle size distribution analysis. It is, however, not without limitations, which will be discussed. (C) 1998 Elsevier Science Ltd.