DEVELOPER of poured asphalt-concrete core wall (core wall made of poured asphalt-concrete) – “B.E. Vedeneev VNIIG” Inc., Saint-Petersburg, Russia, General Director – Dr.tech.sc. E.N.Bellendir.
DESIGNER of rockfill dam of Boguchanskaya HPP – “Istitute Hydroproject” Inc., Moscow, Russia. Chief engineer of the rockfill dam project – I.I. Khabibullin.
OWNER of HPP – “Boguchanskaya HPP” Inc., Kodinsk, Russia. General Director – B.V. Efimov.
GENERAL CONTRACTOR – “Organizer of Boguchanskaya HPP building”, Kodinsk, Russia. General Director – V.A. Uporov.

The design novelty is that the core wall of 77 m height, 1800 m length is not as usually building of  tightened asphalt-concrete  but of poured self-tightened asphalt-concrete mix pouring hot as layers of 40-120 cm height or higher into a formwork of any type (Fig. 1, 2).
Development and use of poured asphalt-concrete core wall is connected with necessity to construct core wall at negative air temperatures (by Celcius) and foundation with strong atmospheric precipitations, i.e. in the conditions when it is impossible to use usual tightened asphalt-concrete for asphalt-concrete core wall construction. In particular, “B.E. Vedeneev VNIIG” Inc. has developed the method to design a composition of a mineral part for asphalt-concrete by the different graininess factor to realize the possibility of poured asphalt-concrete usage in hydroengineering construction.
The poured asphalt-concrete core wall at Boguchanskaya HPP is building at the air temperature to minus 25оC. Special kinds of work allow continue building at the temperature to minus 38оC with 100% grouting of horizontal and vertical joints. Laying rate into metallic knock-down formwork at Boguchanskaya HPP achieves 5000 m3 per month.
Asphalt-concrete mix is transported from the factory both special asphalt trucks and dump trucks; from asphalt trucks the pouring into formwork is carried out directly, but from dump trucks – by transfer using front loader (Fig. 3); it is also possible to pour into formwork just from the body of a dump truck.  After filling it is not needed to tighten the mix by compactor because the specially developed mixes are self-tightened during cooling, at that there is achieved the parameter of residual asphalt-concrete porosity less than 2.8% which is necessary to provide the required impermeability and durability. When asphalt-concrete has got cooled to the normal temperature the formwork is taken away, filled and the contact soil layer is tightened, the formwork is removed and the next layer is poured.
The poured asphalt-concrete core wall is more plastic and bears considerably more deformations without seal failure even at lower temperatures than the core wall made of tightened asphalt-concrete, if it is damaged there occurs self-grouting (self-curing). That is why the poured asphalt-concrete core wall developed for Siberian climate conditions has been recommended by “B.E. Vedeneev VNIIG” Inc. to use in other regions with extremely difficult conditions or soils for structure foundation, or the structure operation or building – on the 101 m height embankment dam of Irganayskaya HPP in the Caucasus on the river Avarskaya Koisu (2007), on the embankment dam with the height to 56 m and 10 000 m length of “Khadita” HPP on the river Euphrates, rockfill dam of 32 m height and 300 m length of Dnepropetrovsk aluminum factory. Operation of these structures has demonstrated the reliability and complete impermeability of poured asphalt-concrete core walls.

Fig. 1.  View of building site of rockfill dam with asphalt-concrete core wall

Fig. 2.  Cross-section of Boguchanskaya HPP rockfill dam
1 – rockfill, 2 – transition soil layers, 3 – asphalt-concrete core wall.

Fig.3. Filling of asphalt-concrete mix just from asphalt trucks and using front loader at the building site of Boguchanskaya HPP