Can Double Surface Dressing Coating support very heavy 110tonnes vehicle movements?

19 Oct 2010 - 09:15
Ian Kirk asked the following:

Currently based deepest part of Sahara, we have a haul road , graded Sahara plain .. 450Km long * 10mtrs wide. Haul Road reasonable condition but suffers from corrugations, soft spots ,worn pitted areas of at time very hard desert plain. We have large tonnage truck movements @tonnage loaded 110 tonnes moving 60km/hr @100 vehicles/day but road used by a variety of other vehicles bringing total vehicle movements to 2000 per day. Could a double surface dressing stand up to the stresses imposed by such vehicle movements , ambient temperature here average 38 degrees. The main highway which looks as if it is made of various BS :4987 basecourse materials has broken up and cracked and suffered thermal movements. Quarry materials suggested size 5-12mm and 12 - 25mm basalt , with psv of 60ish. Sorry at this point we do not have details of CBR values of haul road, no rain , no ice. looks as if plain bituminous binder and cationic emulsion suggested , no mention of any polymers. Hope you can help.... No standards here road no 29, etc if you have any on pdf it would be appreciated.
21 Oct 2010 - 17:01
This requires a specialist consultants answer and a very detailed study of the existing conditions. Both are beyond the scope of this service. Surface dressing is a surface treatment that restores skid resistance adn helps to keep water out of surface that is lightly cracked. It cannot 'paper over' structural defects. Road 29 is no good to you because it is long out of date and does not cover heavy wheel loads, but TRL have published guidance about working in tropical conditions. A search through the TRL Library may be a helpful starting point - www.trl.co.uk/online_store/