FE 07.0323/2023/GTC - Investigation of the mode of action and duration of action of asphalt preservation

In road construction, asphalt pavements have hardly been sealed so far, despite their exposed location. They are therefore freely exposed to environmental influences (UV radiation, weathering, freeze-de-icing salt, etc.). Consequently, depending on these effects, accelerated ageing effects occur, such as the hardening of the asphalt and embrittlement of the binder, which leads to a structural and thus monetary loss of substance or to a shortened service life of the road.

The results of these ageing effects are, for example, cold cracks, fatigue cracks or grain loss, which accelerate the loss of substance of the road due to water penetration into the deeper layers. The result is high repair costs and road closures with high economic costs. In order to avoid this monetary damage and to ensure the performance of the infrastructure in the long term, the approach of asphalt preservation by sealing is to be proven in this project.

According to initial findings, the use of preservatives can significantly delay the ageing and thus the loss of substance of existing asphalt pavements. The economic savings potential of the construction method has also already been proven in individual studies.

The "coating" has been used on asphalt surfaces in the USA for more than 25 years and is already part of the regulations in force there. Various substances can be used in the sealing of asphalt pavements. The majority of products in the USA are based on natural asphalts of one provenance. However, there are numerous suitable deposits that can be used in combination.

Currently, different products are used for preservation on the European market. The main distinguishing feature of the products is the solvent content and the type of binder used. The aim of this project is to investigate the efficacy and technical feasibility of asphalt preservations both on real test tracks and on asphalt test specimens in order to enable an assessment of the effect on service life.

In addition, the economic effect of asphalt conservation on the preservation of the intrinsic value will be investigated in more detail and, for the first time, numerically recorded. This will make it possible to establish asphalt conservation in the technical regulations in the future. As a result, construction practice also has a benefit, as public contracting authorities can put out to tender the asphalt conservation construction method based on well-founded data in the context of the technical regulations.