EXPERIENCE ON DESIGN AND CONSTRUCTION OF ROAD PAVEMENTS USING THE CLAUSES OF EUROPEAN STANDARDS ON HYDRAULICALLY BOUND MATERIALS

Abstract

Hydraulically bound mixtures (HBM) are most effectively applied in the base layers of flexible road pavements to enhance their load bearing capacity and also in the base layers of rigid road pavements in the case of weak soils of the sub-grade. The evaluation of Ukrainian standards which are identical to European standards relating HBM leads to the point of subsequent implementation of new requirements trough design and construction of motor roads in Ukraine. The by European standards stated requirements and classification of HBM provide a modelling regime closer to the performance of bound pavement layer and give the wider range of HBM designations with different strength properties. Thus, this article reviews such aspects of design and construction of road pavements with HBM layers which are distinguished from the conception approved now in Ukraine. The reviewed clauses on design and construction concern road pavements which, in accordance with the European practice, are classified as flexible pavements or semi-rigid pavements and are comprised of flexible (bitumen-bound) upper layers laid on a HBM base. The reviewed types of road pavement constructions are most eligible to emphasize the possibilities of implementation of new standard requirements in the Ukrainian road building industry. As it was concluded, the European standards state classification of HBM by compressive strength RC and classification by tensile strength in combination with elastic modulus Rt, E. These methods of classification are equivalent with no correlation intended between them and have been successfully used during design and construction of road pavement constructions comprised of bitumen-bound layers laid on a HBM base. When designing the motor roads with the above mentioned pavement construction to be loaded with high traffic, HBM of strength classes RС from С8/10 to С9/12 shall be contributed where classes of strength are determined by the type of a hydraulic binder and can be accorded to the categories by ”Rt, E” values not less than T3 (from T3 to T5). Keywords: hydraulically bound mixtures, classification by values of mechanical properties, compressive strength, base layers from hydraulically bound mixtures.