A proposal for sealing deformation joints on hydraulic engineering structures

Superficial asphalt seals in joints of hydraulic structures

“…J e h (2) in which ~: is the safety factor, taken as 1.1-2.0 depending upon the operating conditions, considering that the more pronounced the texture of the mastic, the higher the value of r; t is the design period; and v is the constant rate of opening of the joint.…”

“…At most hydraulic developments built on soft compressible foundations an established practice at the present time is the waterproofing of construction joints with asphalt seals having a cavity measuring 1.5 x 1.2 m (seals used at the Volgostroi). The waterproofing of the joints with asphalt seals 80 x 100 cm in cross section at the Bratsk hydroelectric plant and 60 x 80 cm in cross section at the Plyaviusk hydroelectric plant [3], although sufficiently reliable, was so complicated that at the Krasnoyarsk and Ust'-Ilimsk dams asphalt seals were not used, and the joints were waterproofed with metal compensators.The development, in recent years, of fundamentally new asphalt-polymer waterproofing materials [3] opens up new prospects for the use of superficial asphalt seals under a sharply continental climate [2].At the Sarrans darn in France (1936, height 114.5 m), the joints were waterproofed by means of a reinforcedconcrete beam 1 x 1 m in cross section with an adjacent asphalt seal 7 x 21 m in cross section. Although this seal …”

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Asphalt seals are a reliable method of waterproofing contraction joints of hydraulic structures, especiallywhen subjected to temperature-settlement deformations [1,2]. However, owing to the thermoplasticity of the asphalt filler, it is necessary to have a reliable protection against sharp temperature variations, since under high temperatures the asphalt mastic may flow, and under low temperatures it may lose its plasticity; leading to cracking when the joint is opened or to excess pressure in the seal cavity when the joint is closed.

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