Design & Construction of an Experimental Two Layer Concrete Pavement Motorway Section in Spain

In June 2006, GISA a Public Company, within the Department of Planning and Public Works of the Catalonian Regional Government, awarded CEDINSA the concession for the project of constructing and operating the projects of converting into a dual carriageway the stretch Vic-Ripoll of the C-17 highway. As a participant in the UTE (Joint Venture) designated to carry out the project and with the aim of deepening the knowledge in new technologies for rigid pavements, FCC proposed to the Catalonian Regional Government to take the opportunity to build an experimental section, using a new technology for concrete pavement. The demonstration stretch is located between stations 8430 and 9350 of the design document. This technology consists of placing two layers of concrete of dry consistence made up of different components. Spreading of both layers is done almost simultaneously in such a way that they work jointly when in service. In addition, surface mortar is removed, in order to obtain a negative roughness improving both the traffic comfort and noise-related effects, which are more satisfactory than traditional concrete paving technologies. The upper layer is made up of concrete with a cement content of 460 kg per cubic meter; it has a water/cement ratio of 0.4, an 11 mm maximum siliceous aggregate size and a splitting strength at 28 days over 4.2 MPa. Concrete for the lower layer has a cement content of 390 kg per cubic meter, a water-cement ratio of 0.44 and a required splitting strength of 3.5 MPa at 28 days (i.e, lower than that specified for the upper layer), with a maximum aggregate size of 25 mm. The texture is obtained through the use of a surface retarder followed by a sweeping of the paving’s surface to enable the elimination of a thin layer of unset mortar, resulting in a negative roughness. Once the approval of the Direcció General de Carreteres de la Generalitat de Catalunya (the Regional Government’s Roads Department) was obtained, and under the supervision of technicians from GISA (Gestió d’Infraestructures, S.A.U., the company cited above in charge of the management of infrastructures), the project was carried out in the designated area between March 15th and 18th, 2010, by pouring the lower layer of 21 cm and the upper layer of 4 cm both of concrete. A team from Alpine, an Austrian company subsidiary of FCC, highly experienced in this type of solution, moved special equipment and skilled labor to Spain to execute the experimental section.