WALO has played a pioneering role in the field of bituminous asphalt seals for over 80 years with its various services in Switzerland and worldwide. Apart from sealing reservoirs, canals, landfills and dams, various repairs are also part of our specialist department’s range of services.
WALO offers the bituminous sealing of newly built canals as well as repairs to existing canals.
In newly built canals, the asphalt liner is applied directly after the earthworks. With repairs, the old asphalt liner is initially removed with a milling machine and then asphalted or asphalted directly on the existing subsurface (e.g. concrete) depending on the type of seal in place. With the help of the canal paver designed by WALO, horizontal application is even possible in curves along the entire length of the canal embankment. Slopes of up to 1:1.25 on the canal embankment are possible here. As seen in reservoirs, waterproof connections to the inlet structures etc. are also realised by special joint constructions with expansion elements.
For over 60 years, dams have been made impermeable to water with asphalt core walls. There are more than 200 core walls of this kind 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 seal is installed step by step in layers up to 250 mm thick as the construction of the dam progresses. Bituminous core walls 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 these settlements without becoming damaged or permeable.
In bituminous seal construction, the mastic asphalt seal acts as a thin protective layer or wearing course.
It protects the seal below against UV radiation, amongst other things, thus making an important contribution to extending its service life. The mastic asphalt seal retains its protective function if replaced regularly as required. WALO evens out irregularities in the old layer during the repair of mastic asphalt seals and applies a new seal following thorough cleaning of the surfaces. As with complete repairs using milling machines, mastic asphalt 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 embankment.
In the latter case, the asphalt liner is applied to the embankment facing the water of the finished dam in strips between 2.5 and 6 metres wide. Embankments up to 200 metres long and with a maximum slope 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.
Since the layer is relatively thin yet at the same time extremely flexible in terms of absorbing settlements and deformations, asphalt is the ideal solution for sealing all kinds of reservoirs.
The bottom and embankments of small ponds, snow storage basins, right through to large pump reservoirs – all of which often have flowing geometries – can be mechanically 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 the inlet structures etc. are realised by 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.
We appreciate your interest in the WALO Group and are happy to answer any questions you may have.