1. 2019 Pavement Workshop May 21-23, 2019
Improve Material Inputs into Mechanistic Design Properties for RCA & RAP
Bora Cetin
Assistant Professor
Iowa State University
+ 46 Associate Members

2. RESEARCH TEAM Iowa State University GeoEngineering Consulting, LLC
Principal Investigator – Bora Cetin
Assistant Professor – Department of Civil, Construction & Environmental Engineering
Research Personnel – Patrick Bollinger
PhD Student – Department of Civil, Construction & Environmental Engineering
GeoEngineering Consulting, LLC
Co-Principal Investigator – Tuncer B. Edil
President and Chief Engineer

3. OUTLINE Introduction Research motivation Objectives Research plan
Future expectations

4. INTRODUCTION
Base Course
HMA/PCC/Granular
Subgrade

5. INTRODUCTION 2 billion tons/year aggregate produced (FWHA 2004)
200 million tons/year of RCA and 90 million tons/year of RAP generated (FHWA 2011)

6. INTRODUCTION
Annual Quantity Used
RAP
RCA
From Edil et al. (2012)

7. Use of Material Characteristics
INTRODUCTION
Use of Material Characteristics
Pavement M-E Design
AASHTO 1993

8. INTRODUCTION Range of Materials Reclaimed Asphalt Pavement
Unbound Materials
Reclaimed Asphalt Pavement
Fine-Grained Soils
Recycled Concrete Aggregate
Stabilized Soils
Macadam

9. OBJECTIVES
1st Goal – Establish a database for RAP and RCA materials` characteristics:
Resilient modulus (Mr)
CBR/UCS
Index properties
Construction specifications
2nd Goal – Form a pavement design specification

10. RESEARCH PLAN
Task 1 – Initial memorandum on expected research benefits and potential implementation steps
Task 2 – Data collection
Task 3 – Sensitivity Analyses
Task 4 – Draft/final report

11. Task 2-Data Collection Characterization of RAP & RCA
Stiffness/Resilient modulus (Mr)
Permanent deformation
Shear strength
Index properties
Hydraulic conductivity/permeability

12. Task 3-Sensitivity Analyses
Normalized Sensitivity Index (NSI)
NSI = ∆𝑌 𝐷𝐿 ∆𝑋 𝑋
∆Y = the change in pavement performance due to change in design input
DL = the design limit for the pavement performance parameter
∆X = the change in the design input from the baseline X
X = the baseline design input value

13. Task 3-Sensitivity Analyses
IRI = Roughness
LC = Longitudinal Cracking
AC = Alligator Cracking
AR = Asphalt Rutting
TR = Total Rutting

14. Task 4-Draft/Final Report
Given the complexity of the system and dynamics of Iowa’s ever-changing granular road conditions due to:
Traffic, seasonal and weather conditions, and heavy ag loading; Conditions can change in hours rather than years, so surface condition (although important to know for maintenance purposes); is an ongoing effort and what we really interested in knowing is whether the system can withstand these pressures and continue to provide the desired service to the public.
GRAMS proposes to develop a user-friendly, systemic, risk-based evaluation tool to
Allow county engineers to better
-Tell the Story of Iowa low-vol roads to the public and elected officials.
-Perform meaningful Technical analysis, Based on objective criteria that supports tried and true rule-of-thumb decision making,
-As well as providing a tool to optimize granular resurfacing strategies and policies.

15. SCHEDULE

16. Thank You