First publication: asphalt, Germany, edition 5 | 2020, page 34.
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In 2019, the renowned engineering firm Oppermann GmbH was awarded the contract for planning a residential area in the municipality of Burgwald, Hesse.
The contract included the construction of asphalt roads. To join the asphalt to gutters, joints had to be formed in line with ZTV Asphalt-StB (1). From previous projects, Oppermann was already aware that the formation of joints using the “cutting and pouring” method often did not provide satisfactory results. In particular, it is extremely difficult to create a professional joint around curves. As a result, the joints created using this method were often too wide and the surrounding area was contaminated. After consulting with DENSO GmbH, the engineering firm decided to invite tenders for the formation of joints using the TOK®-Band for the Burgwald project.
Certified bitumen joint tapes for permanent sealing
Bitumen joint tapes have achieved the best results for joints in asphalt traffic areas (Fig. 1) for decades and have long-since established themselves on the market. When selecting the products, attention needs to be paid to the certification of the properties by recognised institutes, which confirm compliance with the regulations. The working group of experts required and specified the formation of joints when combining asphalt mixes with different properties in the ZTV Asphalt-StB for good reason. In addition, joints must be formed when, for example, joining asphalt to gutters or kerbs. Movements need to be absorbed at these points in order to ensure a permanent seal and the bonding of the different building materials. This significantly reduces the risk of damage and ensures a safe, state-of-the-art structure. Moreover, the joint sealant supports the edge of the asphalt, which largely eliminates spalling at the edges.
In rolled asphalt areas, the bitumen joint tape is installed with a 5-mm protrusion of the tape. This protrusion is automatically rolled into any breaks at milled edges when compacting the asphalt so that they are reliably sealed.
When using mastic asphalt, the TOK®-Band can be installed flush due to the different construction (no roller compaction). This type of design has also been established for many years and is described accordingly in the ZTV Fug-StB. Similarly, when installing asphalt in “compact construction”, bitumen joint tapes have been used with optimal results for years.
The construction work in the Hessian municipality was completed by Heinrich Naumann GmbH und Co. KG from Münchhausen. The asphalt was mechanically installed with an asphalt finisher. Hirsch GmbH took over responsibility for the joints on behalf of Naumann.
For 30 years: TOK®-Band convinces
The TOK®-Band was cost-effectively and professionally installed using an installation unit developed by Hirsch (Fig. 1). Hirsch has long been a partner of DENSO GmbH, the manufacturer of the TOK®-Band in Leverkusen. The method is impressive in practice, as explained by Managing Director Andreas Hirsch: “At Hirsch GmbH, we have been installing the TOK®-Band for over 30 years. We cannot imagine a better method of installation, especially for curves, such as those at traffic islands. The joints are formed quickly and cleanly and no damage is caused.”
Naumann also successfully uses this construction. “The TOK®-Band efficiently creates completely reliable joints. For us as a construction company and for our clients, ensuring clean and reliable work by our partner companies is the top priority. Quality is simply a must. This is absolutely the case with Hirsch as well as the TOK®-Band”, confirms Site Manager Frank Kesting.
When working with great lengths, mechanical installation is recommended to facilitate the work. This may take place using an installation unit or in situ with the TOKOMAT® (Fig. 2). In this case, the bitumen joint tape from the TOK®-Riegel is manufactured on-site and installed directly along the edge. In the warm and plastic state, the sealant can optimally adapt to irregular edges, such as natural stones.
TOK®-Band: Permanently high quality - confirmed by independent institutes
Both the ready-made TOK®-Band as well as the TOK®-Riegel joint sealant used with the TOKOMAT® method are certified and approved joint materials in accordance with the TL Fug-StB. The suitability of the materials was verified in an initial test. Besides this, external monitoring by an independent test institute accredited in line with the RAP Stra (4) is conducted three times a year. This strict, independent quality audit ensures a consistently high and enduring quality. By contrast, in many cases no external monitoring is required for products certified under the European standards, such as the hot applied sealant types N1 and N2 in line with DIN EN 14188-1 (5).
The benefits of the bitumen joint tape were clearly visible when joining the road asphalt to gutters in the Hessian municipality: rapid installation in exceptional quality. The method is extremely efficient and reduces the construction time, as no second traffic closure is required, as is the case when using the pouring method. The bitumen joint tape should be the preferred solution for asphalt surfaces as the joint is always in the right position and no cutting can occur alongside.
(1) ZTV Asphalt-StB 07/13, “Zusätzliche Technische Vertragsbedingungen und Richtlinien für den Bau von Verkehrsflächenbefestigungen aus Asphalt“, FGSV, Cologne 2013
(2) TL Fug-StB 15, "Technische Lieferbedingungen für Fugenfüllstoffe in Verkehrsflächen“, FGSV, Cologne 2015
(3) ZTV Fug-StB 15, “Zusätzliche Technische Vertragsbedingungen und Richtlinien für Fugen in Verkehrsflächen“, FGSV, Cologne 2015
(4) RAP Stra “Richtlinie für die Anerkennung von Prüfstellen für Baustoffe und Baustoffgemische im Straßenbau“, FGSV, Cologne, 2015
(5) DIN EN 14188-1, “Joint fillers and sealants - Part 1: Specifications for hot applied sealants; German version EN 14188-1:2004”, Berlin, 2004.
DENSO Group Germany
For almost a century, DENSO Group Germany has built its reputation on high-quality and forward-thinking solutions for sealing technology and corrosion prevention. DENSO products - Made in Germany - reliably protect road construction, buildings, pipelines and station construction. With branches in six European countries DENSO Group Germany is leading the key Central European markets and continues its dynamic growth in Eastern Europe, Asia, Africa, and South America with sales partners in over 100 countries worldwide.
You can find more information on denso-group.com.