Optimizing Concrete Pavement Type Selection Based on Aggregate Availability
Design concept and structural responses of jointed plain concrete pavement (CPCD) and continuously reinforced concrete pavement (CRCP) are quite different. In CPCD, concrete volume changes are allowed to a full extent, and accommodations are made to ensure good load transfer at discontinuities, i.e., transverse contraction joints. On the other hand, concrete volume changes are restrained to a significant degree in CRCP by longitudinal reinforcement and base friction. Because of this vastly different behavior between the two pavement types, concrete with a high CoTE is not an ideal material for CRCP. In other words, the performance of CRCP with a high CoTE concrete will be compromised, with resulting spalling. Concrete with a high CoTE should be used for CPCD if at all possible. This study investigated the correlation between spalling and concrete CoTE. CRCP sections with severe spalling were identified. Sections with no spalling and delamination distresses were also identified. A minimum of two cores were taken from those sections, and CoTE and modulus of elasticity were evaluated. There was an excellent correlation. Concrete material properties of selected coarse aggregates were extensively evaluated in the laboratory. Also, an in-depth analysis was made of the life-cycle cost of the pavement with coarse aggregates from different sources. Concrete with a CoTE larger than 5.5 microstrain per °F is quite prone to severe spalling. The findings from this study indicate that, if concrete with a CoTE greater than 5.5 microstrain/°F is used in CRCP, the risk of severe spalling increases substantially. Accordingly, if the only coarse aggregate type available locally produces concrete with a CoTE greater than 5.5 microstrain/°F, it is strongly recommended that this aggregate not be used in CRCP. Instead, the use of CPCD should be considered. Whether low CoTE aggregates need to be brought in for use in CRCP, or a locally available high CoTE aggregates is utilized in CPCD, should be based on the local experience with CPCD performance.