Effect of Portland cement Concrete Mix Properties, Thickness, Joint Layout and Traffic Loading on the PMED Software Predicted Distresses in Jointed Plain Concrete Pavement

Abstract

Between  September  2022  and  March  2023,  Transportation  Association  of  Canada  (TAC)  Mechanistic  Empirical  (ME)  Pavement  Design  Subcommittee  completed  five  sets  of  design  trials  using  the AASHTOWare Pavement ME Design (PMED) software to assess the effects of portland cement concrete (PCC) mix properties, coefficient of thermal expansion (CTE), slab thickness, dowel diameter, joint spacing and traffic loading on the predicted distresses in jointed plain concrete pavement (JPCP). The trial results using software v2.6 indicated that a better quality concrete results in improved performance in terms of predicted international roughness index (IRI), faulting and cracking. Only a high CTE of >8.0x10‐6/ºC seems to affect the predicted transverse cracking. Varying climate was shown to have significant effect on the predicted  IRI,  a  lesser  effect  on  the  predicted  faulting  and  no  or  negligible  effect  on  the  predicted  transverse cracking. The trial results also showed some inconsistencies and significant differences in the predicted distresses between software v2.6 and v3.0.  
The trial results using software v3.0 showed that an increase in the PCC thickness results in an increase in the predicted IRI and faulting, which is not expected. An increase in the PCC thickness showed a reduction in the predicted transverse cracking. The trial results also showed that thicker dowels provide a significant reduction in the predicted faulting and IRI, but have no or minimal effect on the predicted transverse cracking. PCC joint spacing showed no or minimal effect on the predicted IRI, a significant effect on the predicted joint faulting for PCC layer thicker than 200 mm and for high CTE values and a significant effect on the predicted transverse cracking. Traffic loading has a small effect on the predicted IRI. The minimum PCC thickness should be 205 mm and CTE should be 8.0x10‐6/ºC to produce an impact of traffic loading on the  predicted  faulting.  Transverse  cracking  is  highly  sensitive  to  traffic  loading  with  thinner  concrete.  Overall, a high CTE value has shown a greater impact on the predicted performance than joint spacing and PCC thickness, which seems to be unreasonable and requires further investigation.