• Sadowski, Lukasz

Abstract

The durability of concrete floors is to a high degree determined by the pull-off adhesion of the topping to the structural layer. Both when making and repairing concrete floors it is crucial to prepare the surface of the structural layer in order to obtain proper bonding. The measure of the latter is the adhesion value determined by the pull-off test. The search for concrete floor areas lacking adhesion at the interface between the layers was the subject ofpaper by Delatte who on the basis of pull-off test results produced a map showing the areas where delamination occurred. Also Garbacz proposed to use the pull-off method to obtain a map of delaminations on the surface of laminar concrete elements. However, the pull-off method is much less suitable for evaluating the bond between the layers or locating the places or areas in which there is delamination at the interface between the layers. In thelatter case its effectiveness depends on the number of drilled boreholes. The larger the number of boreholes, the larger the number of places in which the floor needs to be repaired after the tests. It seems that this problem can be solved by applying nondestructive methods, i.e. the impulse response method and the impact echo method.In this study the impulse response method and the impact-echo method were used in comparative tests of the interlayer bond in a model concrete floor specimen. The surface of the specimen’s structural layer was prepared in two ways, i.e. half of the surface was mechanically ground in order to increase adhesion, whereas the other half remained in its original post-concreting condition. The aim of the study was to find out how the results btained using the above nondestructive methods would differ for the two ways of preparing the bonding surface.

Topics

• impedance spectroscopy
• surface
• laser emission spectroscopy
• durability