The Mechanistic-Empirical Pavement Design Guide (MEPDG) is a tool developed by NCHRP used to aid engineers in pavement design and performance analysis. MEPDG is currently incorporated into the software program AASHTOWare Pavement ME Design. In order for the software to perform at the highest level of accuracy, AASHTO recommends a local calibration of inputs to be performed.
The purpose of this research study was to provide additional material inputs for Portland cement concrete to the proposed catalog of inputs developed based on research performed as part of a previous NCDOT research project, RP2015-03 and evaluate the impact of these inputs on the predicted performance of North Carolina rigid pavements.
To accomplish this, concrete mixtures with varying materials and proportions were batched and tested for mechanical properties, thermal properties, and durability performance.
A range of findings related to the impact of fly ash content and aggregate types/sources onmechanical/thermal properties and durability performance along with information on the time-dependent change of selected properties and durability prediction measurements is presented. An expanded catalog of input values was prepared for NCDOT’s consideration for use in future pavement design.
JPCP pavement layers
Pavement ME Design (PMED) software is the latest tool for design and performance analysis of rigid pavements. Simulations were conducted using PMED software to evaluate the effects of concrete material inputs, climate, and input levels on the performance and design slab thickness of jointed plain concrete pavements (JPCP) and unbonded concrete overlays.
The simulation results were analyzed, and the detailed findings are presented in this report. It was found that the coefficient of thermal expansion (CTE) is the most significant material input affecting the JPCP design and performance. The other thermal properties including heat capacity and thermal conductivity also significantly affect the design and performance of rigid pavements and using PMED default values for these inputs may result in under designed pavement systems.
It was also found that the strength gain for concrete paving mixtures that include fly ash takes longer to gain full strength. Level 3 material inputs restrict an accurate representation of fly ash’s strength gain properties with only the 28-day compressive strength value while Level 1 material inputs simulate a better depiction of how fly ash properties are included in JPCP pavements. The findings of this report will help the pavement engineers towards improved design of rigid pavement systems.
