De invoering en het gebruik van nieuwe contractvormen heeft in de afgelopen jaren de verhouding tussen opdracht - gever en opdrachtnemer sterk veranderd. Steeds vaker wordt er gebruik gemaakt van geïntegreerde contracten waaraan ook onderhoud wordt gekoppeld - de DB(F)M-contracten. Dergelijke contractvormen leggen meer verantwoordelijkheden neer bij de opdrachtnemer, waardoor ook meer risico's bij de opdracht nemer komen te liggen. De opdrachtnemer is door deze ontwikkeling wel beter in staat de werkzaamheden aan te passen op zijn of haar uitvoeringsmogelijkheden, maar ook komt hierdoor de verantwoordelijk- heid voor het functioneren van de constructie (mede) bij hem terecht. Dit zorgt ervoor dat procesbeheersing en de verbetering van kwaliteit meer aandacht vragen van de uitvoerende partijen.

Recent significant changes in public sector procurement in the Netherlands are forcing road construction companies to professionalize one of their primary processes: on-site asphalt paving. This paper describes an initiative aimed at improving quality in the process. A literature review confirmed that research into the asphalt paving process seems to be in a state of infancy. Interviews with on-site plant operators confirmed that operational choices in the asphalt paving process depend heavily on craftsmanship and that the work methods and equipment are mainly selected on the basis of tradition and custom. Also, the operators were reluctant to use new (available) technologies. Since improving the paving process requires integrating new technologies with the learning of new work methods, this paper proposes an action research strategy. Such an approach involves operators and researchers in addressing the apparent mismatch between current technology development, work methods and the operators' (tacit) operational strategies.

Maintenance of flexible paved roads is faced increasingly with time constraints and spatial limitations. As a consequence rather often the maintenance process has to be carried out under less favorable circumstances, e.g. adverse weather conditions. It raises a number of questions, such as; “how do less favorable circumstances affect the quality of work?”, and, “how should the operating procedure of the maintenance process be adapted to unexpected or changing conditions?” The paper presents the results of a research project that focuses on the compaction process of asphalt pavements to determine the impact of varying conditions during this process. The main objective is the design of a simulation tool for the compaction effect of a roller under varying external conditions. During the compaction process material behavior is mainly elastic-plastic due to the reorientation of the particles. Large deformations can occur and, because of that, also large strains. Therefore, an elastic-plastic non-linear analysis is carried out to examine the relations between roller and material properties and the compaction result. Within the DiekA model, an Arbitrary Langrange Eulerian FEM approach, a material model derived from soil mechanics and called “Rock model” is implemented. This model describes material behavior in an elastic-plastic manner and has a closed yield locus. Calculations with the model show a realistic stress and strain pattern in the asphalt mix under a static roller while compacting. In the project, a field experiment has been set up to validate the model.