A New Parameter Based on Fractography to Assess Mechanical Properties of New-to-Old Concrete Interface Employing Probability Density Function of the Height of Fractured Surface

Abstract

This study discusses an effective parameter for the mechanical properties of new-to-old concrete interface of concrete specimens. The authors employed probability density function (PDF) of the height of fractured surface and the standard deviation from it for discussion, which is the main feature of this study. The conclusions are as follows. 1. The fractured surface of new-to-old concrete interface is able to be modeled to a specific shape (such as a square pyramid or a square pillar) by evaluating the PDF of the height of the fractured surface and finding the same PDF of the specific shape. Modeling the real fractured surface to such a simplified surface body to a dowel has a potential to clarify the mechanical properties of the interface. 2. The standard deviation (Sd) calculated from the PDF of the fractured surface and some parameters employed in the previous studies (such as roughness parameters and fractal dimensions) have a close relation. The Sd value of the specimen is a better parameter than the ones used in the previous studies for evaluating the mechanical properties of new-to-old concrete interface.�