Repairs with High-Performance Concrete

 

Modeling and Computational Verification of Effectiveness

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Thin (TWT: 10-20 cm) or ultra-thin (UTW: 5-10 cm) concrete wearing courses (whitetopping) can be built on old asphalt and concrete pavements to eliminate deformation damage, e.g. ruts or washboard-like bulges. High-performance concrete (HPC) or ultra-high performance concrete, or UHPC for short, is used to construct ultra-thin pavements. Such concretes have long been used successfully in structural engineering wherever extreme compressive strength and slender structures are required. In addition, the high resistance to chemical attack (chlorides, de-icing salts) should also be mentioned as an important property that qualifies UHPC for use in road construction in particular.

However, ensuring the desired properties requires the highest standards in manufacturing. The aim of the research project is therefore the development of basic principles for the superstructure of existing conventional concrete layers with UHPC slabs. In doing so, information on the mode of action and suitability of such measures and on the influences of various boundary conditions is to be developed with the aid of FE simulations. The boundary conditions to be investigated include the bond between the layers, the effect of bond bolts, the distributions of stiffnesses, constraints due to (partially) hindered temperature strains in the fixation, horizontal displacements of the layers as well as the effect of dowels in the existing concrete layers including possible mislocations of dowels. Furthermore, different geometric configurations have to be investigated and the influence of storage conditions on the overall bearing behavior has to be estimated.

Detailed studies of damage mechanisms (crack propagation, etc.) are not addressed within the scope of this work. The findings are to be prepared in the form of a report in such a way that they serve as a dimensioning aid for setting up large-scale tests on new repair construction methods using UHPC at the Federal Highway Research Institute.