CRCP with Ground Texture – Experiences and Results of the Geseke Access Road Pilot Project

In 2009, an innovative road pavement "Continuous Reinforced Concrete Pavement with Ground Texture" was successfully realised by HeidelbergCement AG with the pilot project, "Geseke access road ". In an extensive measurement programme, long-term measurements are being made over a period of 5 years to investigate the behaviour of the carriageway under traffic, as well as the evolution of surface characteristics of the ground textures, e.g. noise reduction and skid resistance under high heavy traffic load. The scientific backing and measurements are being carried out by the Ruhr University Bochum (RUB) and the German Federal Highway Research Institute (BASt). The aim is to create a lifespan and economic efficiency forecast for the CRCP with ground texture based on these measurement values. For the dimensioning of the CRCP, the road concrete class StC 35/45 - 4.0 according to AL-Sp Beton 06 [1] has been taken as a basis. The road is driven on daily by approximately 500 clinker and limestone transport lorries with a total weight of 40 t. The approximately 1 km-long and 7.50 m-wide road was built with a longitudinal and transverse reinforcement made from steel bars (0.75 % reinforcement). The concrete (strength class C35/45 - XF4, XM2 according to DIN EN 206-1) [4] with a thickness of 22 cm was installed using a slipform paver onto a 10 cm thick asphalt base layer. The texturising of the surface with a grinding process used for the first time in this new construction has shown that an extremely quiet and high-grip surface texture can be produced with this type of surface finishing. Through the grinding or profiling of the surface, all the irregularities created during the construction of the concrete were eliminated, therefore enabling the construction of an absolutely flat surface with extremely high driving comfort and outstanding driving dynamic properties. By means of a longitudinally aligned texture geometry with a defined grinding depth and groove and gap width, the drainage of the surface water is influenced positively, which leads to a reduction in spray generation and the risk of aquaplaning, and therefore leads to a substantial improvement in road safety. Two different groove spacings were implemented on the test section (blade distance 2 mm and 3 mm / blade width 3.2 mm / grinding depth 3 mm). Very good results were measured with the Close Proximity Method (CPX) as well as with the Lateral Force Measurement method (SKM) with regard to noise reduction and grip in 2010 and 2013 (e.g. grinding 2 mm: CPXP,80 km/h 94.9 / 95.2 dB(A) and ?SKM,60 km/h 0.84 / 0.81). The HeidelbergCement AG "Geseke access road" pilot project proved impressively that all the requirements of a modern, quiet, roadworthy and low-maintenance construction are safely and sustainably fulfilled through a jointless CRCP with ground texture.