Nonlinear aggregate interlock model for concrete pavements

Abstract

The objective of the study was to develop a constitutive model that captures the nonlinear behavior of shear load transfer through aggregate interlock. A stepwise linear model was proposed. The model parameters were determined by optimizing numerically predicted to experimentally measured slab deflection basins. Continuous measurements of concrete deflection basins and truck loading were obtained using a specially designed large-scale slab tester. The numerical simulations were conducted using ABAQUS/Standard Version 6.2. Excellent deflection reproducibility was achieved for a wide range of crack widths and concrete containing different coarse aggregates. As expected, the results show that as the crack width increases, aggregate interlock is governed by the crack pattern and aggregate size. If the coarse aggregates are fractured, aggregate size does not affect aggregate interlock. The model was successfully incorporated in the pavement analysis tool EverFE 2.24 to demonstrate the significance of aggregate interlock on the efficiency of dowel retrofit across cracks. Further work is recommended on calibrating the model parameters using time-history data from falling weight deflectometer data at cracks and joints.

Keywords:

• Aggregate interlock
• Concrete pavement
• Constitutive model
• Crack surface

Acknowledgements

This work was sponsored by the Michigan Department of Transportation (MDOT) under the MSU-UM Pavement Research Center of Excellence program, the Center for Advanced Cement Based Materials (ACBM), and by MTS Systems Corporation. The model development is part of the Ph.D. dissertation of the first author. The authors would like to thank William Davids for help with EverFE. MDOT assumes no liability for the content or use of the results of this study. This work does not constitute a standard, specification, or regulation.