In 1976/77 test facilities belonging to English Clays Lovering Pochin & Co Ltd at St Austell, Cornwall, were hired by the transport and road research laboratory to study the behaviour of coarse granular solids (limestone aggregates up to 50 mm diameter and colliery spoil) when pumped as slurries with water through a steel pipe of 156 mm diameter. That work, which was reported in TRRL report SR 354, was in 1979/80 extended to 102 and 207 mm pipes, using limestone aggregates only. The results with limestone aggregates in all three pipe sizes are now presented. The hydraulic gradient was measured for slurries containing both narrowly-graded and broadly-graded aggregates with four different maximum sizes,over a range of velocities up to about 6 m/s, at concentrations generally between 5 and 20 per cent by volume (about 10 to 40 per cent by weight). from the hydraulic gradients the specific energy requirement was calculated in kilowatt hours per tonne kilometre of payload. The results are presented largely in graphs and tables together with a brief discussion and a bibliography of papers on coarse-particle slurry behaviour. (Author/publisher)
Abstract