Abstract The quality of processed sands is a critical issue for several construction applications (asphalt mixes, concrete, granular layers). The sand flow test is commonly used to control this quality. High accuracy video-capturing equipment is now also used to characterize the shape of aggregates. The objective of this study is to model the relationship between the actual shape of sand particles, measured using a video-capturing equipment, to the sand’s flowing time in a hopper, in order to eliminate the need for sand flow laboratory measurements. Several samples of processed and natural sands were tested using on the sand flow test equipment used in the European standards. The shape of the particles was then analyzed using a video-capturing equipment. A simple empirical relation was found between the shape factor of particles by Beverloo’s law and the actual shape of particles, characterized by a shape index defined in this study. The results were then confronted with the sand test equipment specified in the ASTM standards, to validate this empirical relation. The coefficients in this new relation had to be experimentally determined according to definition of the particle’s diameter, the video system, and the sand flow test equipment. The discharge coefficient was also taken into consideration. This is mainly experimental work; the physical explanation of this relation would have to be analyzed in greater depth in the future.
[1]
J. van de Velde,et al.
The flow of granular solids through orifices
,
1961
.
[2]
Julius J. Komba,et al.
Analytical and Laser Scanning Techniques to Determine Shape Properties of Aggregates
,
2013
.
[3]
M. Ammi,et al.
Effect of gravity on mass flow rate in an hour glass
,
1995
.
[4]
Yuji Tomita,et al.
Experimental investigation of a free falling powder jet and the air entrainment
,
2001
.
[5]
D. Maza,et al.
The flow rate of granular materials through an orifice
,
2007,
0707.4550.
[6]
Joseph Anochie-Boateng,et al.
Three-dimensional laser scanning technique to quantify aggregate and ballast shape properties
,
2013
.
[7]
D. Maza,et al.
Flow and Jamming of Granular Matter Through an Orifice
,
2009
.
[8]
Beena Sukumaran,et al.
Influence of inherent particle characteristics on hopper flow rate
,
2003
.
[9]
Aibing Yu,et al.
Prediction of hopper discharge rates of binary granular mixtures
,
1998
.
[10]
M. Gundogdu.
Discharge Characteristics of Polydisperse Powders through Conical Hoppers. Part 1: Predictions for Fine, Granular, Free Flowing Powders
,
2004
.
[11]
U. Tüzün,et al.
Flow of binary mixtures of equal-density granules in hoppers—size segregation, flowing density and discharge rates
,
1990
.