Factors influencing pull-off tests on concrete

Abstract

The pull-off technique has grown in popularity for testing the surface zone strength of concrete, and when used in conjunction with partial coring is particularly suitable for the bond testing of repairs. Theoretical and laboratory experimental studies have been undertaken to examine a number of important practical factors which influence the results obtained during surface and partially cored pull-off tests. Finite-element methods were used to analyse failure zone stress distributions. Disc material and proportions were shown to be particularly significant in both types of test, and in some circumstances the results are also affected by the elastic modulus of the concrete. These factors may influence correlations with compressive strength, demonstrating the importance of standardization of disc characteristics to permit direct comparisons of results. This will also be an important consideration when comparing measured test results with specified values. A very wide range of loading rates is provided by currently available test equipment, and this feature merits further study, together with other factors relating to partially cored tests as applied to repairs.

A comparative study of the surface glaze characteristics of concrete treated with CO2 and high power diode lasers Part II: mechanical, chemical and physical properties

“…These aspects were: the pull-off strength; the surface roughness; the rupture strength; the wear resistance and the corrosion resistance. 4 To determine the strength of the bond between the CO 2 and HPDL generated glazes on the OPC surface and the concrete substrate itself, pull-off tests were conducted based on the work of Bungey et al [1] and Carino [2]. For experimental convenience the concrete was prepared as relatively small area samples (25 mm x 25 mm).…”

Variability of the Pull-off Technique for Adhesion Strength Evaluation on Ceramic Tile Claddings

“…It is necessary to mention that European standards EN 1015-12 [22] and EN 1348 [23] recommend the use of metallic discs with thickness higher than 1 cm. Bungey et al [29] refer 2 cm for steel metallic discs. Therefore, a constant (1 to 2 cm) thickness of metallic discs should be used in pull-off tests on ceramic cladding adhesion testing.…”

Hybrid Metaheuristic-Neural Assessment of the Adhesion in Existing Cement Composites

“…This method is time consuming due to the delay time of the curing of the resin used for bonding the steel disc. Moreover, results can be influenced by variation on the rupture surface, the orientation and position of the aggregate onto the disc, the disc material, diameter, and thickness, the backpressure system, and also the speed of load application [6][7][8]. The tested surface in each of the measuring places is damaged and the efficiency of this method depends on the number of measuring places.…”