Study on expression method for grading of coarse aggregate for concrete

Grading control of coarse aggregates is important to secure the workability of concrete stably. In this report, the actual state of the grading of coarse aggregates was investigated with the existing surveys and the expression method was studied. At the result of study, modified Rosin-Rammler’s equation could be applied to express the grading of coarse aggregates, those are river gravel and crushed stone. Three experimental constants used in the equation were set and the important point of grading control was suggested in each grading.