1. Presentation 2 Phase A – Deformation Studies
A. Abu Abdo

2. Phase A: Mix Resistance to Deformation (E* and GS/CEI)
Tasks
Literature Review
Analytical Analysis
Agg and Binders Evaluation
Preparation and Evaluation of HMA Mixtures
Data Analysis
Phase A Reports

3. Experimental Program

4. Mix Matrix
4 Aggregates Structures (Fine Mix, SP3, SP4 and Coarse Mix).
8 Binders; PG 70-34, PG 70-28, PG 70-22, PG 64-34, PG 64-28, PG 64-22, PG and PG
7 Field Mixes.

5. Aggregate Gradation

6. 8 22 13 PG High Grade PG Low Grade -34 -28 -22 70 AC% -0.5 Opt 0.5
Coarse Mix 8
Mix 1
> 30x106 22 13
Mix 2
3 - 30x106
Fine Mix 64 58
17 mixes –
Total Number of Lab mix samples = 265
Total Number of Field mix samples = 49

7. Field Mixes In addition to MnROAD Mixes Mix PG AC% APA E* GS/Jc/Jc*
1. (Jerome IC)
70-28
4.90% 2 3
2. (Topaz to Lava)
60-34
4.35%
3. (Lapwai to Spalding)
5.40%
4. (US 95/SH 6)
58-34
6.20%
5. (US 20)
5.12%
6. (SR270)
5.90%
7. (SR270)
5.10%
Total 14 21
In addition to MnROAD Mixes

8. Tests Binder G*, and Master Curves - Completed
Gyratory Stability (GS) - Completed
E* and FN - Completed
APA (In progress)
Image Analysis

9. Data Analysis

10. Gyratory Stability, GS

11. Gyratory Stability
Ndesign
Gyratory Stability, GS =  SN . de
NG1

12. GS Sensitivity to Binder Content Changes
The GS values were calculated for Mix 1 and Mix 2 at different asphalt contents; Optimum and ±0.5AC% from optimum, all these mixes were designed to achieve four percent Air voids. As per Superpave Mix Design, these mixes should perform best at the optimum asphalt content, at which the air voids of the compacted specimen at N-design is four percent. As shown in the Figure, both mixes yielded the highest GS at -0.5% AC from optimum instead of at optimum asphalt content. It is believed that the decrease of binder content led to higher GS values due the increase of friction between aggregate particles.

13. GS Sensitivity to Different Binder Grades
Mix 1
Mix 2
GS sensitivity to binder type (PG grade) was evaluated for these two mixes. It was speculated that GS would not capture the changes in binder grade, since GS is determined while compaction, when all binders are heated to achieve the same viscosity (0.28±0.30 Pa.s) and the difference in grade does not influence the performance of the mix at these temperatures. The results showed as expected that overall GS is not very sensitive to the changes in binder grade.

14. Lab vs. Field Mixes
To evaluate the possibility of utilizing GS as a quality control tool in the field, GS values for lab mixes were compared to field mixes. When tested, Field Mix 1 had different mix properties than the mix design (lab mix). Field Mix 2 exhibited the same mix properties as the mix design. When GS was compared for lab and field mixes, it was found that GS could capture the changes in mix properties as shown this Figure. Results showed that GS for Mix 1 changed with the change of mix properties (e.g. Gmm). Mix 2 GS values were the same for field and lab mix due to no change has occurred in mix properties

15. Field Mixes
GS was evaluated for other five field mixes . A trend has been observed, the lower the asphalt content the higher the GS values, due to the increase of friction and interlocking between aggregate particles

16. Initial Results
Flow Number, FN

17. FN vs. GS (Field Mixes)

18. Initial Results
Dynamic Modulus, E*

19. G* - PG 70-28
E* - PG (Mix 1)

20. Master Curves
G* - PG 70-28
E* - PG (Mix 1)