Road Marking on Concrete Roads

On several of the concrete roads that were constructed in Sweden during the 1990s problems have been experienced in making the road marking compound adhere to the road surface. The problem would appear to be greatest during the first few years. In earlier studies, the problem was analysed by laboratory research and by inspection the road markings on concrete roads in Sweden. The studies have resulted in recommendations for improving adhesion between the road marking compound and the concrete surface: ? Mechanical cleaning of the surface with a wire brush or by milling ? High-pressure washing of the concrete surface ? Drying of the surface ? Treatment with primer ? Laying road marking compound with a thickness of 3–4 mm A field test was carried out in autumn 1999 on the E20 road at Eskilstuna to verify the recommendations. Three different marking products were studied: ? Thermoplastic, extruded compound ? Thermoplastic, spray compound ? Cold plastic compound, single component, acrylic-based The field test has so far shown that the recommendations that have been drawn up give good results as regards thermoplastic compounds. For cold plastic compounds, results are more difficult to interpret. The weather conditions during laying were not suitable for the cold plastic compound which is sensitive to moisture and low temperatures. It was difficult for the cold plastic compound to harden at the low temperature prevalent at the time of laying. After the first winter all the cold plastic road markings had separated from the surface to which they had been applied.