Report on the thermal International Conference at Bad Meinberg

Abstract

The author gives the characteristics, specifications and constructional processes of items that are very important in road building: the rock sub-base, and the pavement sub-base. He refers specially to the base layers of low cement content, which are recommended for heavy traffic pavements. The construction of the rock sub-base has been difficult to control so far, and is an important technical problem, owing to the risk of differential road settlements under the action of heavy overloads. In the specifications to which this papers refers, obtained from the performance of experimental pavements in Britain, the maximum size of the materials are fixed with accuracy, also their proportioning, the thickness of the layers and the best methods of compaction. This is the source of novelty of the specifications. Poor concrete bases, with proportionings of about 6% by weight, provide greater stiffness for flexible pavements, so that their thickness is twice the equivalent of a granular base. This reduces the difference in cost of both pavement designs.