Innovative sieve simulation and microstructure image analysis techniques for estimation of aggregate size distribution in hardened concrete

Aggregate size distribution is one of the most important parameters affecting the strength and workability of concrete. Therefore, estimating aggregate size distribution from hardened concrete samples can be utilized to evaluate the quality of the concrete mixture. For this purpose, an innovative and comprehensive method was developed in which images of the macrostructure and microstructure of hardened concrete were utilized. Macrostructure images were analyzed to extract coarser aggregates (retained on the 0.3 mm sieve). A simulation of the mechanical sieving was developed to assess the passing of each aggregate based on relative translational and rotational motions of the aggregate image with respect to the apertures. This simulation can be claimed as the most accurate method for examining the passing of aggregates through sieves using 2D images. In addition, some geometric rules were hired to optimize the computational costs of the simulation. In order to determine the volume ratio of finer aggregates (passing the 0.3 mm sieve), two relationships between the mass and volume of concrete phases and hardened cement components were considered. Finally, the volume ratio of finer aggregates was estimated by using these relationships and by analyzing microstructure images containing high resolution image for calculating air voids area ratio and BSE image for calculating hardened cement components area ratios. Comparison of the results from the proposed method with actual grading highlights the brilliant performance of the proposed method in estimating aggregate size distribution.