Labour-based bitumen roads as cost-effective alternatives to conventional gravel wearing courses

As part of the Gundo Lashu Programme for Labour Intensive Rural Roads Maintenance that is currently being implemented in Limpopo Province, South Africa, the training of 24 emerging contractors in rehabilitation of rural gravel roads was carried out. All 24 contractors went through an extensive practical and theoretical training programme and have completed their first Trial Contracts, which formed the second step in their development programme. They are currently executing larger Standard Contracts after which they will emerge into the open market. South African rural roads generally carry much more traffic than the rural road network in the rest of sub Saharan Africa with many gravel roads carrying up to 1000 vpd. At the lower end, there is a vast network of district and community access roads carrying less than 100 vpd, which is largely unimproved and maintained only as bladed tracks. In addition, there are probably hundreds of thousands of kilometres of unimproved village roads and streets. The potential for large-scale application of labour-based road works is therefore enormous. Delivery of a quality product is seen as key to the acceptance of labour-based road works. In Gundo Lashu it was realised early on that finding good quality wearing course gravel in itself constituted a major problem in many areas of the province, thus bringing the costs for a fully rehabilitated and gravelled 5.5m wide road to about R230 000 in some instances. Aside from depleting an increasingly scarce resource, construction and maintenance of conventional gravel roads would be very costly. An assessment of different options for the provision and maintenance of a good gravel wearing course, in financial and economic terms as well as suitability for labour-based operations was carried out. This indicated that better use and/or improvement of in situ material by emulsion or chemical stabilisation in combination with provision of various low cost bituminous seals results in lower predicted life-cycle costs than the gravelling option for the roads in question. Aside from the potential financial/economic benefit, the alternative solutions would have considerable intangible or non-quantifiable benefits such as reduction of dust pollution, reduced negative environmental impact and conservation of valuable resources in the form of gravel deposits. Labour-based contractors can use the techniques assessed successfully on roads carrying up to 200-300 vpd and thus cover a large proportion of the rural road network. Aside from retaining the employment benefit, the potential savings in construction and maintenance costs may be used to construct more roads and thus provide a larger proportion of the rural population with good quality all-weather access roads of an appropriate standard and contribute to economic development of previously