This investigation was aimed at studying the effect of test methods on bond strength between concrete substrate and repair material. Four test methods with cementations or modified-cementations repair materials, and two surface roughnesses were studied. The methods used were pull-off, slant shear, splitting prism and a new direct shear named Bi-Surface shear test. While the coefficient of varia...

The direct shear test is a widely used method of determining peak and critical state strength parameters for soil and for soil-manufactured material interfaces. However, stress conditions inside the box during shear are not well known. This paper presents a new micromechanics-based approach that modifies existing relationships between plane strain and direct shear friction angles taking into ac...