320 likes | 709 Views
INVERTED BASE Pavement Design Ju ne 1, 2010 The Virginia Experience. Randy Weingart, P.E. Director: Materials Management / Product Research Luck Stone Corporation Richmond, Virginia. Inverted Base. Characterize the materials for use in the Mechanistic design equations for the ICAR protocols
E N D
INVERTED BASEPavement DesignJune 1, 2010The Virginia Experience Randy Weingart, P.E. Director: Materials Management / Product Research Luck Stone Corporation Richmond, Virginia
Inverted Base • Characterize the materials for use in the Mechanistic design equations for the ICAR protocols • Design an inverted base using the ICAR Model and compare to the current MEPDG AASHTO model • Estimate comparable construction and material costs of alternative designs.
Primary Outcomes • Develop and Document a Case study for an Inverted Pavement application • Design • Construction and Instrumentation • Periodic Performance testing • Collaborative effort between Industry, VDOT and FHWA • Provide knowledge to Pavement Design Community of alternative performing design choice • Demonstrate predictive aspects of ICAR model relative to actual documented performance.
Test Section - Current Design48+00 to 53+00 500 ft Current Design - Instrumented Inverted Design
Test Section - Inverted Design53+00 to 58+25 500 ft Inverted Design Inverted Design
Original Section Inverted Section 1.5" SM-9.5D 2" HMA Surface 2.0" IM-19.0A 3" HMA Intermediate 6" Unbound Aggregate Base 7.5" BM-25.0 3.0" ODGL (Open Graded Drainage Layer) 10" Cement Treated 8.0" Cement Treated Sub-grade (Design CBR 5.0) Untreated Subgrade 10,000 psi
PAVEMENT DESIGN BULL RUN BYPASS • MEPDG (Mechanistic Empirical Pavement Design Guide) • ICAR (International Center Aggregate Research)
Advantages of ICAR Approach • ICAR Considers the UAB (Unbound Aggregate Base) as a nonlinear and stress sensitive particulate medium. • ICAR models account for directional dependency of the stiffnesses in the unbound layer (Anisotropic vs Isotropic behavior) • Accurate modeling of UAB stress states • Gives realistic stress distribution • Eliminates or reduces significant horizontal tension
Nonlinear Anisotropic Ex= 0.3 Ey Linear Isotropic Ex = Ey 25 38 20 30 15 25 10 5 20 0 -10 15 -20 10 -30 5 -40 2 Pavement Response AnalysisHorizontal Stress in Base layer
= EASL ( ADT ) ( T ) ( T ) ( G ) ( D ) ( L ) ( 365 ) ( Y ) f Traffic Calculation Design Period ADT % Truck Growth Rate Growth factor Truck Factor % Truck in Design Lane ESAL 30 10,000 0.21 0.05 66.44 0.413 0.85 17,877,353 25 10,000 0.21 0.05 47.73 0.413 0.85 12,842,399 20 10,000 0.21 0.05 33.07 0.413 0.85 8,897,381 15 10,000 0.21 0.05 21.58 0.413 0.85 5,806,356 10 10,000 0.21 0.05 12.58 0.413 0.85 3,384,457 5 10,000 0.21 0.05 5.53 0.413 0.85 1,486,836
Original Section Inverted Section 1.5" SM-9.5D 2" HMA Surface 2.0" IM-19.0A 3" HMA Intermediate 6" Unbound Aggregate Base 7.5" BM-25.0 3.0" ODGL (Open Graded Drainage Layer) 10" Cement Treated 8.0" Cement Treated Sub-grade (Design CBR 5.0) Untreated Subgrade 10,000 psi
Construction Cost Comparison - Original Section vs. Inverted Section
Potential Savings • Original section $20,640 per 100 linear ft • Inverted section $16,071 per 100 linear ft • Difference of 22.14%
INVERTED BASEPavement DesignJune 1, 2010The Virginia Experience Randy Weingart, P.E. Director: Materials Management / Product Research Luck Stone Corporation Richmond, Virginia