A 4pt bending bond test approach to evaluate water effect in a composite beam

Abstract

Considering that water may cause a separation of interfaces between layers of pavement structures, specific test on bi-layer specimens is performed in a water bath. For the study of the bond between layers made of cement concrete overlay on bituminous material, four-point bending results show a competition between different failure mechanisms. Actually a very good bond resistance between layers compared to the fracture tension resistance of the cement concrete layer is preliminary observed in dry conditions. In this work, first results of the water effect on the behaviour of such a material interface are presented. The final fracture length of the specimen and the corresponding curve of force-displacement highlight the influence of water immersion on the debonding failure mode. The field displacement measurement obtained by Digital Image Correlation is used to improve the understanding of the fracture scenario.

Keywords:

• Crack
• debonding
• four-point bending test
• water effect
• DIC
• heterogeneous material

Acknowledgements

The authors are grateful to Sofiane Guessasma, Octavian Pop, Marc François and Guillaume Le Gallec for their help of using DIC analysis.