Investigations in Kenya and Malawi using as-dug laterite as bases for bituminous surfaced roads
In Kenya 1974/5 and in Malawi 1984/5 trial sections of bituminous-surfaced low volume roads were constructed using as-dug laterite in place of stone or stabilized material as a base course.
The laterite did not conform with any accepted specifications but performed equally well when compared with adjoining sections of road using stone or stabilized material as a base.
The construction procedures employed are described. A period of 4–6 weeks between the compaction of the base and its surfacing is considered essential if the road is to perform satisfactorily. During this period it is exposed to the weather and traffic or to periodic watering and rolling. This treatment fills any cracks with dust or mud and closes them by the kneading action of rubber-tyred traffic. The bituminous surfacing is applied where the base has dried out to about half the optimum moisture content and is extended about 1.5 m beyond each edge of the carriageway.
In 1984, $40000 US per km was saved in Malawi in this way, approximately 70% being in convertible currency without incurring additional maintenance or vehicle operating costs.
KeywordsLaterites roads developing countries
Unable to display preview. Download preview PDF.
- Charman, J.H. (1988)Laterites in Road Pavements, CIRIA Special Publication No. 47, London: Construction Industry Research and Information Association, pp. 17–19.Google Scholar
- Der Bundesminister Fur Verkehr (1959) Zusatzliche Technische Vorschriften und Richtlinien fur Erdarbeiten in Strassenbau.Google Scholar
- Grace, Henry & Partners (1983)Keny Low Volume Roads Study, Institution of Civil Engineers Library, London.Google Scholar
- Grace, Henry & Partners (1988)Malawi Low Volume Roads Study, Institution of Civil Engineers Library, London.Google Scholar
- Grace, H. and Toll, D.G. (1987) Recent investigations into the use of plastic laterites as bases for bituminous surfaced roads, presented at the4th International Conference on Low Volume Roads, University of Cornell. Transportation Research Record 1106, Vol. 1. pp. 80–88, Washington, Transportation Research Board.Google Scholar
- Grace, H. (1974)Low cost roads in desert areas, Arab Engineers Federation Kuwait Conference.Google Scholar
- Lundgren, R. (1969) Field performance: General report speciality sessions engineering properties of laterite soils, presented at the7th International Conference of Soil Mechanics and Foundations Engineering, Vol. 2, pp. 45–7.Google Scholar
- Queiroz, C., Carapetis, S., Grace, H. and Paterson, W. (1991) Observed behaviour of bituminous surfaced low volume laterite pavements, presented at5th International Conference on Low Volume Roads, Raleigh, North Carolina, USA.Google Scholar
- Townsend, F.C., Krinitzsky, E.L. and Patrick, D.M. (1982) Geotechnical properties of lateritic gravel,ASCE Speciality Conference on Engineering and Construction in Tropical and Residual Soils, Honolulu, Hawaii, pp. 236–262, New York: American Society of Civil Engineers.Google Scholar
- United Nations Development Programme (1972) Northern Nigeria Roads Study, United Nations, New York.Google Scholar
- World Bank Policy Study (1988)Road Deterioration in Developing Countries — Causes and Remedies, Washington: World Bank.Google Scholar