Hybrid strengthening system for road maintenance
In the project precast concrete elements for the rehabilitation and upgrading of urban traffic areas were developed, theoretically investigated and tested in construction practice.
New materials for use in urban infrastructures contribute to the execution of measures aimed at achieving a durable and consistent construction that is conducted in an energy and resource efficient way, thereby supporting sustainable mobility. An efficient and lasting road infrastructure constitutes the basis for a successful economy. In future, durable strengthening and repair systems with fast construction times are needed to guarantee the availability of roads. Modular systems that can be implemented quickly are therefore to be tested for the targeted and optimal use of future available resources. In the research project on the subject of “New materials for urban infrastructures (HighTechMatBau)” - that is being sponsored by the Federal Ministry of Education and Research (BMBF), precast concrete units are modelled and developed for repairing urban road surface structures, for example bus stops, junctions and roundabouts.
In a first step, a dimensioning process was developed that, among other aspects, takes into account the impact of traffic and temperature, the geometry of the precast units and the effect of the base layer in a sufficiently accurate way. All parameters for the precast as well as for the underfill and bedding material which are relevant to the dimensioning had to be clearly defined in this process. It was furthermore necessary to determine the parameters that describe the interaction between the different construction materials, for example the bonding between the concrete and underfill material (silicate resin) layers.
Based on this, the precast system was mapped with the corresponding base layer with the help of a 3D FEM model. In the ongoing project, the FEM model is constantly calibrated and further developed using an iterative approach based on results which will be generated from small-scale and large-scale tests.
The manufactured concrete part demonstrator will be used to investigate in particular the lateral force transmission of different coupling systems. Among other things, defined mechanical loads by simulation of wheel rollovers (MLS30) in the joint area as well as the metrological determination of the load carrying capacity by means of FWD will be carried out. The investigations are planned until the end of 2018.
The demonstrator produced in the HESTER research project on the duraBASt serves not only to assess the practical feasibility of construction for highly stressed urban areas, but in particular to analyse and test innovative coupling systems.
Initially, it is planned to put this technology into practice for the repair of bus stops. The first successful applications took place in August 2017 and in May and June 2018 in Berlin.