ADHESION BETWEEN LAYERS IN FLEXIBLE PAVEMENTS

The adhesion between the wearing courses or upper bituminous layers, and the roadbase is an important factor in the rheological behaviour of a bituminous surfacing subjected to static and dynamic loads. A study is made of the strength of flexible pavements by defining some types of failure and by giving special consideration to the adhesion between layers. The study is based on laboratory experiments. The following conclusions are drawn: (1) excess in the quantity of the binder in some surface treatment is harmful for not only does it affect the adhesion between the upper layer and the roadbase but it can also harm the stability itself of the upper bituminous layer; (2) the use of emulsions, which are easily diluted in water, permits small quantities to be utilized per square meter; furthermore, if there is insufficient curing at a later stage, this does not have such serious consequences as regards final adhesion; (3) uneven roadbases should be avoided as they cause the formation of zones with too much or too little binder. The number of the covering abstract of the annual meeting is 100980. /TRRL/