Effect of PCC Strength and Stiffness Characterization on MEPDG Predicted Performance of JPCP Structures

摘要

The hierarchical approach for specifying design inputs is a key feature of the new Mechanistic-EmpiricalPavement Design Guide (MEPDG). The three levels of design inputs for Portland cement concrete (PCC)strength and stiffness characterization range from level 1 laboratory measurement of modulus of elasticityand modulus of rupture at 7, 14, 28, and 90 days to level 3 estimation of the 28-day unconfinedcompressive strength. This paper evaluates the effect of design input level for PCC strength and stiffnessproperties on MEPDG performance predictions for jointed plain concrete pavements (JPCP). The effectof the different PCC stiffness and strength design input levels on predicted faulting, transverse cracking,and IRI are evaluated for eight different PCC mixtures in several different JPCP design scenarios.Faulting was found to be insensitive to the MEPDG PCC input level, transverse cracking was extremelysensitive, and IRI was only moderately sensitive. Most important, the results show that the level 3 inputcombination of measured 28-day modulus of rupture and measured 28-day modulus of elasticity yieldedpredicted distresses that were consistently in closest agreement with predictions using level 1 inputs.Reliable and accurate 28-day modulus of rupture and modulus of elasticity values can therefore be used asa less expensive alternative to full level 1 stiffness and strength characterization in JPCP analysis anddesign. When full level 1 characterization is performed, high quality testing is required to avoid smallanomalies in measured values that can lead to physically unrealistic predictions of stiffness and strengthgains vs. time by the MEPDG.