Hydraulic structures such as power station dams, water reservoirs, canals and dikes for protection of coasts, rivers and harbours, frequently require a protective coating against the effects of waves, flowing water, and water pressure. These protective surfaces must be immediately and permanently effective, withstand very heavy loads, have long durability, and be flexible and easy to repair.
Asphalt-a mixture of aggregate and bitumenfulfils these requirements to a very great extent.
The properties of bitumen and its behaviour in relation to the requirements, is explained by examples. The composition of, asphalt and its application are discussed. Methods of construction are described.
Almost all over the world we observe every day how bitumen-mixed with stone aggregate to form asphalt-is used for road construction, even in circumstances which from the construction and traffic point-of-view are trying. It may, however, be less known that some thousand years ago, hydraulic engineers of the ancient world used asphalt for the construction of river embankments as mortar to fill the joints of brick and stone walls. Large parts of these structures are still intact today, serving their purpose and thus demonstrating the efficiency and durability of this material's.
Having lost its importance during later centuries, due to the preference given to other materials, until it was practically forgotten, asphalt began, some thirty years ago, to regain attention and has become an established and indeed an essential material for hydraulic structures during the last decade. The increasing demand for water and hydraulic power of expanding industries, the growing importance of navigation and waterways as well as the need to provide for efficient coast protection presented challenges also to hydraulic engineering that can only by D. ROSE, BP Benzin und Petroleum Aktiengesellschaft, Germany.
Rsum Des constructions hydrauliques e.a. des usines hydrauliques, rservoirs d'eau potable ainsi que digues pour la protection des ctes, des fleuves et des ports exigent souvent des revtements de protection contre l'attaque des vagues, courants et pressions. Ces revtements doivent tre efficaces et d'un effet immdiat, rsistants aux plus hautes charges, de faon durables et flexibles et facilement rparables.
Asphalte-bitume incorpor aux minraux-peut satisfaire toutes ces exigences.
La proprit des bitumes en fonction des exigences imposes est explique l'aide d'exemples. La composition des asphaltes et ses possibilits d'emploi sont discutes. Des mthodes de constructions sont dcrites. be met by developing rational and efficient construction methods using approved materials. Basic research, test results and experience gained in asphalt road construction on the one hand show that the use of bitumen can be the answer to construction problems which, in the past, seemed almost too difficult to be solved. On