Particle size distribution analysis of coarse aggregate using digital image processing

An attempt at applying the digital image processing (DIP) technique to analyze the particle size distribution of coarse aggregate is made. Three different types of aggregates have been analyzed, and their grading curves are compared to those obtained by conventional mechanical sieving. Because DIP produces only area gradation and uses a particle size 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 gradation is proposed. Moreover, a size correction factor is used to convert the particle sizes measured by DIP to equivalent square sieve sizes so that comparison between the DIP and mechanical sieving results can be made. The study demonstrates that DIP is a fast, convenient, versatile, and accurate technique for particle size distribution analysis. It is, however, not without limitations, which will be discussed. (C) 1998 Elsevier Science Ltd.