Design of coarse-medium-fine aggregates proportion and analysis of air void contour curves

Document Type

Article

Publication Date

2022

Department

Department of Civil, Environmental, and Geospatial Engineering

Abstract

In order to make the mineral mixture meet the engineering requirements and reasonably match the aggregate particles with different particle sizes, the distribution range of aggregate particle sizes in the mineral mixture was analyzed. The aggregates were divided into three grades: coarse, medium and fine aggregates, and a triangular coordinate system with coarse aggregate proportion as horizontal axis, medium aggregate proportion as vertical axis and fine aggregate proportion as oblique axis was established. A design method of coarse, medium and fine aggregate ratios based on the triangular coordinate system was proposed. With the particle size ratio and initial particle size as indexes, a total of 27 combinations of coarse, medium and fine aggregates were built and each combination had 36 mixing proportions. Through the discrete element simulation, the air void ratios of 972 virtual samples were calculated and the results were plotted in contour maps. The influences of coarse, medium and fine aggregates combinations and mixing proportions on the mixture air voids were studied. Analysis results show that the initial particle size has negligible impact on the air void ratio. The particle size ratio has a great influence on the air void ratio, and gradually decreases with the increase of the particle size ratio. The air void ratio contours show obvious trend. The contours become denser and the regional rules become more and more obvious with the increase of the particle size ratio. The initial particle size and particle size ratio are two types of indexes for the mixture proportion, which have different effects on the void ratio, and the latter can be used as the main index. The influences of volume proportions of coarse, medium and fine aggregates on the void ratio show contour change with regional characteristics in the triangular coordinate system. The maximum void ratio appears near the apexes of the coordinate, and the minimum void ratio appears near the midpoint of the lateral axis. The void ratios on both sides against the oblique axis are significantly different, with a maximum of about 2. 8%. The void ratio below the oblique axis is relatively small. The convex points of the void ratio contours point to the apexes of the vertical axis, the concaves point to the middle of the lateral axis, and the density of the curves indicates the difference degree of the void ratios. 8 tabs, 8 figs, 53 refs.

Publication Title

Jiaotong Yunshu Gongcheng Xuebao/Journal of Traffic and Transportation Engineering

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