Asphalt Hydraulic Engineering

WALO offers bituminous membrane solutions for newly built canals as well as repairs to existing canals.

In newly built canals, the asphalt liner is installed directly after the earthworks. In the case of repairs, the old asphalt liner is initially removed with a milling machine and then asphalted, or is asphalted directly on the existing subsurface (e.g. concrete) depending on the type of waterproofing membrane present. With the help of the canal paver designed by WALO, the membrane can even be installed horizontally in curved sections along the entire length of the canal embankment. Gradients of up to 1:1.25 on the canal embankment are possible here. As seen in reservoirs, waterproof connections to the inlet structures and so on are also created using special joint constructions with expansion elements.

For over 60 years, dams have been made impermeable to water with bituminous core membranes. There are more than 200 core membranes of this kind currently in use worldwide in dams up to 150 metres in height.

An asphalt liner wall is built inside the dam at the same time as the support body is filled. Using core pavers specially developed by WALO, the membrane is installed step by step in layers up to 250 mm thick as the construction of the dam progresses. Bituminous core membranes are particularly recommended in regions that are vulnerable to earthquakes since the viscoelastic and ductile properties of the asphalt liner mean that it can compensate for any settlement that occurs without becoming damaged or permeable.

In bituminous membrane construction, the asphaltic mastic seal coat acts as a thin protective layer or wearing course.

It protects the membrane beneath it against UV radiation, amongst other things, thus making an important contribution to extending its service life. The asphaltic mastic seal coat retains its protective function if replaced regularly as required. When repairing existing seal coats, WALO evens out irregularities in the old layer and applies a new seal coat following thorough cleaning of the surfaces. As with complete repairs using milling machines, asphaltic mastic can also be repaired if there is water below the surfaces to be repaired. Suitable barriers prevent the materials or any pollutants from entering the water.

Dams can be made impermeable to water by both a sealing layer on the inside of the dam wall (core wall) as well as an external sealing layer on the dam’s embankment.

For this external sealing, the asphalt liner is applied to the water-facing side of the dam’s embankment in strips between 2.5 and 6 metres wide. Embankments up to 200 metres long and with a maximum gradient of up to 1:1.5 are possible here. The high resistance of the asphalt to mechanical influences (e.g. ice drift) means that no additional measures are needed to protect the sealing layer. The asphalt liner is environmentally friendly and non-toxic, making it also ideal for dams containing drinking water.

With a relatively thin structure that can still flexibly compensate for settlement and deformations, asphalt is the ideal solution for sealing all kinds of reservoirs.

The base and embankments of small ponds, snow storage reservoirs, and everything up to large pump reservoirs – all of which often have flowing geometries – can be machine-lined with asphalt reliably and quickly by WALO. Stresses caused by large temperature and load changes are absorbed and relieved by the asphalt liner. Waterproof connections to inlet structures or similar are realised using special joint constructions with expansion elements.

We can renew surface seals in need of repair on both a small and large scale.

The old asphalt liner is removed using milling machines that can also operate on embankments with slopes up to 1:1.5 thanks to special winch cars. The new asphalt liner is installed following the subsequent cleaning and preparation of the surfaces. The repair work can also be carried out above water, i.e. when there is water below the surfaces to be repaired. Suitable barriers prevent the materials or any pollutants from entering the water.