Repair of concrete road pavements with thin-layer new concrete

Duration: 01.08.2012 - 31.07.2014

Concrete pavements are subject to a variety of stresses during their service life, mainly from traffic and weathering. In view of the increasing traffic load as well as high stresses due to freeze-thaw attack, ever higher demands are being placed on concrete pavements in terms of durability. Against this background, the maintenance and repair of traffic surfaces is becoming increasingly important. The rehabilitation of concrete pavements with thin-layer new concrete is a largely new field. The decisive questions as to how a durable bond between old and new concrete can be ensured and which parameters have a particular effect on this were investigated in relevant studies on composite systems with thin-layer new concrete on existing old concrete, taking into account typical loads in concrete pavements. Following a flexural swell load on large-format beams with or without additional freeze-thaw loading, adhesive tensile and adhesive shear strengths were determined on cores taken. It was found that the moisture condition of the substrate at the time of concreting as well as the application of a bonding bridge only play a minor role with regard to bond strength. The use of a soft consistency of the new concrete with a higher compressive strength of the old concrete, on the other hand, had a positive effect. In the course of the production of the new concretes with shrinkage reducer, it became apparent that the air contents in the fresh concrete could only be adjusted with difficulty and that the air void characteristics in the hardened concrete were not achieved in some cases.