Zero Stress Condition Construction Gradients Moisture and Heat At set: Slab Temperature = 105 F Gradient = +0.5 F/in Gradient = 0 F/in Stress as a Result of the Construction Gradient
Measuring Slab Response to Environmental and Applied Loads Instrumentation - Useful in the calibration/validation of models.
Pavement Design Bridge Design 1.Define critical load and axle configuration 1.Accumulate damage of each vehicle load for each hour of the day of each mth of the year
Pavement Design INPUTS Layer thickness Material properties Environmental conditions Axle loads and volumes STRUCTURAL MODEL FATIGUE DAMAGE MODEL n N CALIBRATION WITH FIELD DISTRESS OUTPUTS Cracking Faulting IRI Traffic, moisture & temperature prediction models, material models PROCESSED INPUTS
Models Consider Changing Conditions Time, years Traffic No Units PCC Strength Base Modulus Subgrade Modulus CTB Time increment 2864 0
Current Design Approach: INPUTS Slab thickness k-value ESAL PCC M r OUTPUTS PSI STATISTICAL REGRESSION MODEL Concrete Mixture Properties: Modulus of rupture (28 day) Elastic Modulus (28 day)
New MEPDG Design Guide Inputs Concrete Mixture Properties: Modulus of rupture (7, 14, 28 & 90 day, 28 day to 20 yr ratio) Elastic modulus (7, 14, 28 & 90 day, 28 day to 20 yr ratio) Poisson’s ratio Unit weight Thermal coefficient of expansion Drying Shrinkage Thermal conductivity Heat capacity Mixture Design Information Cement type w/c ratio Aggregate type Set Temperature Information Zero stress temperature Zero stress temperature profile
1. Project Title: Evaluation of the R1-37A Rigid Pavement Design Procedure Sponsoring Agency: Federal Highway Administration Pitt Expenditures/Duration: $100,000/1 year Collaborators: ARA, AET PI: J. Vandenbossche INPUTS Layer thickness Material properties Environmental Conditions Axle Loads and Volumes STRUCTURAL MODEL FATIGUE DAMAGE MODEL n N CALIBRATION WITH FIELD DISTRESS OUTPUTS Cracking Faulting IRI PROCESSSED INPUTS Traffic, moisture & temperature prediction models, material models
2. Project Title: Investigate the Design and Construction of Composite Pavement Systems Sponsoring Agency: SHRP 2/National Academy of Science Pitt Expenditures/Duration: $102,000/4 year Collaborators: ARA, U of Mn & UCDavis PI: M. Darter Objective: Focus on debonding, built-in curl and joint (crack) formation Pitt’s Role 1.Instrumentation of test sections 2.Use of instrumentation data for model calibration/validation (Bolander et. al. 2007) A PCC surface placed over a just placed PCC layer (“wet on wet”).
3. Project Title: Using Falling Weight Deflectometer Data with Mechanistic-Empirical Design and Analysis Sponsoring Agency: Federal Highway Administration Pitt Expenditures/Duration: $51,000/1.5 year Collaborators: ApTech, MSU PI: K. Smith Rigid Pavements 1.Backcalculate layer properties 2.Detect voids 3.Characterize joint performance NDT Sensors NDT Load r
4. Project Title: The Development of a Design Procedure for Thin and Ultra-Thin Concrete Pavements Sponsoring Agency: Federal Highway Administration Pitt Expenditures/Duration: $330,000/3 year PI: J. Vandenbossche Primary Concerns 1.Characterize effects of fibers 2.Bond strength/degradation Adapted from ACPA & Rosler
5. Project Title: Establish Inputs for the New Rigid Component of the Mechanistic-Empirical Pavement Design Guide Sponsoring Agency: PennDOT Pitt Expenditures/Duration: $509,000/3 year PI: J. Vandenbossche Primary Efforts 1.Material characterization 2.Pavement instrumentation Moisture and Heat
6. Project Title: Premature Deterioration of Jointed Plain Concrete Pavements Sponsoring Agency: PennDOT Pitt Expenditures/Duration: $257,000/1.5 year PI: J. Vandenbossche Material Characterization Strength development Fracture toughness Thermal coefficient Drying shrinkage Environmental loads Axle loads and volumes Structural Model