Characterization of concrete pavement joint surfaces

In many concrete structures especially pavements, the ability to transfer shear load across crack/joint and the cracking resistance are important. This research was conducted in order to develop a testing method and roughness parameter that could better predict the shear load transfer across crack/joint. In addition, the research intended to improve both the joint shear stiffness and concrete cracking resistance through the selection of proper concrete constituents. In the study, fractured concrete surfaces resulting from various aggregate types, sizes and gradations were manufactured. A 2D laser profiling device was developed to capture the fractured surface profiles. Existing surface parameters, such as surface roughness number, volumetric surface texture ratio and fractal dimension, were calculated to represent the surface's roughness. The study showed weak to no correlation between the existing roughness parameters and the shear load transfer ability. Therefore, a new surface parameter called Power Spectral Area Parameter was developed and validated in order to better predict the shear load transfer across crack/joint. Wedge splitting test was conducted in order to correlate the concrete's fracture energy with the shear transfer ability. The fracture energy was able to represent both the concrete's fractured surface and shear load transfer properties for several coarse aggregate types and sizes. Strong, large and gap-graded coarse aggregates could improve concrete joint and cracking performances compared with weaker, smaller-sized and dense-graded aggregate mixes.