Concrete slot drains for Dutch de-icing salt support bases

Wherever substances hazardous to water are filled, handled or stored, they must be prevented from getting into the groundwater. De-icing salt is one of these substances: if it seeps into the groundwater, it can cause extensive damage. In addition to the standard longitudinal drainage along roads, it is necessary to ensure the “safety” of storage and handling sites for de-icing salt. Strict requirements are therefore placed on the drainage systems of these sites. A good solution to this problem is applied in the Netherlands, where a special drainage system is used in the refurbishment of numerous so-called road support bases.

In the Netherlands, our neighbor to the northwest, the road support bases located in the vicinity of motorways are referred to as “Wegensteunpunten” (WSP). The support bases are used to store equipment and de-icing salt and mainly serve the purpose of black ice control and incident management. Road inspection vehicles and gritting vehicles set out from here to do their work on the motorways. The authority in charge of operating these support bases is “Rijkswaterstaat” (RWS), which is responsible for the construction and maintenance of roads and waterways in the Netherlands. 42 of 55 road support bases will be either newly built or refurbished as part of the “Wegensteunpunten Rijkswaterstaat” program. One third will be new construction, one third will be substantially refurbished, and the remainder will be only slightly modified. The goal is for all support bases to be state of the art by 2026. One of these support bases, located in Den Bosch, was officially opened on 7 April, 2022.

Rinninger supplies DIBt-approved slot drains

Special slot drains supplied by concrete producer Rinninger based in the Allgäu town of Kißlegg were used to ensure proper drainage of the support base. Jurgen Smeets from Jura BV based in Meerssen near Maastricht is Rinninger’s exclusive sales partner for the Benelux countries and describes the specific features: “The slot drains from concrete producer Rinninger used in this project have various national technical approvals. The RIKI drainage system complies with the strict requirements and stipulations specified by the German Institute for Structural Engineering (Deutsches Institut für Bautechnik; DIBt) in Berlin and may therefore also be used in areas dealing with substances hazardous to water. This includes the road support bases storing de-icing salt.”

Reduce carbon emissions with RiKi-Ceton

An important and distinctive feature of the slot drains, however, is the RiKi-Ceton ultra-high performance concrete used in their production. Ceton is an ultra-high-performance concrete with ductile properties complying with DIBt general national technical approval No. Z-74.4.178. It represents a new generation of concrete because, despite the use of binders with reduced clinker content, it has significantly improved product properties in comparison to a standard concrete. With a flexural strength of between 16 and 20 N/mm² and a compressive strength of 129 N/mm², the material has properties that are similar in magnitude to those of metals but without any loss in ductility. “The special feature of this concrete is that it allows the reinforcement to be reduced both in the channel element and in the substructure,” explains Jurgen Smeets. “And because the drains are of monolithic design and feature cast grates, they can always be checked quite easily for the required tightness. Lengths of 4 m ensure quick installation requiring only a few workers. All of these factors have a very positive effect on the carbon footprint, which definitely plays a major role when it comes to awarding contracts,” says Smeets.

After Houten, Baarn, Nijmegen, Wieringerwerf, Delfgauw, Staphorst and Zevenaar, the Den Bosch “Wegensteunpunt” was the eighth support base to be completed as part of the refurbishment program – 20 more bases will follow. Jurgen Smeets is certain: “The slot drains from the Rinninger concrete plant in the Allgäu town of Kißlegg will be used in these projects, too.”