Published: June 2009 | Category: Activity management , Research programme , Research & reports | Audience: General
A study of cores from multilayer chipseals shows that fine solid materials (passing 4.75 mm) fill a significant proportion of the chipseal volume that would otherwise be available for bitumen.
If fines are ignored, the available voids are typically about twice the expected volume of bitumen that would be sprayed. Generation of fines may therefore contribute significantly to premature flushing.
The origin of these fine materials remains to be examined; at least six different processes may contribute, and the relative contributions may vary from site to site.
Keywords: aggregate, bitumen, chipseal, fines, flushing, spray rates
