H P PFIFFNER AND W FLEMME from Swiss construction company Walo Bertschinger have replied to Lance Carter’s Letter to the Editor which was published in the July 2001 issue of IWP&DC. Carter was asking for information about construction methods of reinforced concrete placed on steep, sloping reservoir walls. One of the Walo Bertschinger’s specialities include the construction of jointless asphalt sealings for all kinds of dams, reservoirs and canals, either for new construction or refurbishment.

Currently the company is designing asphalt blankets for all kinds of slopes up to an inclination of 1:1.3. It has different types of equipment to place the various asphalt mixes and its certified laboratories work according to Swiss and German asphalt standards.

The systems, applied in hundreds of projects worldwide, are impervious, flexible and stable on slopes. The different asphalt layers are placed in structures with varying slope length from the bottom to the crest in lengths from 3-6m, in structures of uniform slope length (canals) in a horizontal placing method with a bridgetype placing machine. The asphalt mixtures are accepting deformations because of settlements of up to 10% of its diameter. See www.walo.ch for more details.

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