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Frictional resistance of coal dust fouled uniformly graded
aggregates
F. N. Okonta
Department of Civil Engineering Science, University of
Johannesburg, P. O. Box 524, Auckland Park, 2006
South Africa. E-mail:
fnokonta@uj.ac.za. Tel: +27 11559 2318. Fax:
+27115592342.
Accepted 8 May, 2012 |
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Large deposits of coal over vast expanse of lands attract
mining companies, power stations and petrochemical companies
and thus the development of coal towns with rail and road
networks. High traffic volume of large quantities of coal
across coal cities often result in the gradual accumulation
of fine coal dust particles on road pavements, rail ballast
and sleepers. The effect of coal dust on the Direct Shear
Friction Angles (DSFA), Direct Shear Interface Friction
Angles (DSIFA) and Direct Shear Modulus (DSM) of uniformly
graded gravel aggregate were investigated. The results show
that at increased coal content, the DSFA of the gravel tends
to the DSFA of the coal. The rate of decrease of DSFA was
dependent on the moisture content of the coal fouled gravel.
The DSIFA was higher than the DSFA at any degree of coal
fouling. The DSM at small displacement was more sensitive to
changes in moisture content of the fouled gravel than
friction angles and is thus a better indicator of coal
fouling effect.
Key words:
Angle of friction, gravels, direct shear strength, interface
shear strength. |
