This report describes the problems of dust emitted from unpaved roads in developing countries through the action of traffic. The significance of the loss of material is discussed in terms of the increased regravelling requirement and attention is drawn to the effect that dust has on traffic accidents by reducing visibility. It describes a study in Kenya which measured the rate of loss of airborne fine materials dispersed from the road relative to the speeds and types of vehicle. Recent experimental studies in the United States of America and Canada are reviewed together with a summary of their results. Methods are also reviewed of utilising bitumens, chemicals, waste chemicals and local materials for dust-proofing unpaved roads, and a critical appraisal is made of the techniques. The conclusions of the research are that most of the dust proofing treatments currently available vary considerably in their effectiveness and, with the exception of the local materials, are usually more expensive than bituminous surface dressing. Where the latter techniques are unavailable, chemical stabilisers can provide an alternative solution. (Author/publisher)
Samenvatting