1. Louisiana Accelerated Pavement Research Facility
Zhong Wu, Ph.D., P.E.
Louisiana Transportation Research Center (LTRC)
Louisiana Department of Transportation and Development (LADOTD)
Louisiana State University (LSU)
4/14/2019
Project status

2. APT Devices ALF (9,750 – 18,950 lb; Uni-directional loading)
ATLaS (0 – 30,000 lb; Bi-directional loadig)

3. Recent APT Projects
Evaluation of Bonded Concrete Overlay over Asphalt under Accelerated Loading (on-going)
Accelerated Load Testing of Geosynthetic Base Reinforced Test Sections (on-going)
Roller Compacted Concrete over Soil Cement under Accelerated Loading (completed)

4. Bonded Concrete Overlay
The Louisiana DOTD has great interest in determining if thin bonded concrete overlays (usually 2-6 in.) are a suitable and cost-effective alternative to the current practice for medium- to high-volume roadway maintenance, which consists of
an existing asphalt concrete layer over a PCC or cement- stabilized soil base.

5. Bonded Concrete Overlay Sections
Detailed layered information of test sections
Section 2
Section 3
Section 1
Three sections constructed
Section 2 (4’’) completed
Section 3 (2’’) standby
Section 1 (6’’) under testing

6. Test Results of Section 2 (4” PCC)
Load sequence
Cracking area
9 kips
16 kips
Pumping
Cracking

7. Crack Mapping of Section 2
0.7M EASL
1M EASL
1.1M EASL
1.3M EASL
1.4M EASL
1.5M EASL

8. Section 1 (6” PCC) under Testing
Load sequence
9 kips
16 kips
After approximately 500,000 varied ATLaS wheel loading, No cracking found yet!

9. Accelerated Load Testing of Geosynthetic Base Reinforced Test Sections

10. Objectives
Evaluate the benefits of geosynthetics for subgrade stabilization and reinforcement of base aggregate layer in flexible pavements built on soft subgrade soils;
Evaluate the effect of pre-rut of unpaved sections on mobilization of geosynthetics, their benefits and performance;
Evaluate the design parameters of geosynthetic reinforced flexible pavement for incorporation them into the context of 1993 AASHTO pavement design and M-E pavement design guide.

11. Heavy clay (A-7-6), Mexico Limestone, Level 1 Superpave
Test Lane Sections
Six test lanes of different reinforcement configurations were constructed,
The dimensions of each section: 80 ft. long and 13 ft. wide.
10 in.
18 in.
6 in.
TENCATE
RS-580i
Tensar
TX-5
12 in.
Sand
3 inch
Heavy clay (A-7-6), Mexico Limestone, Level 1 Superpave

12. Results of ALF Test Lane Sections
Accumulated surface permanent deformation
Testing Criteria: All sections will be loaded to ¾” rut depth.
Experimental studies by different researchers indicated
10 in.
18 in.
6 in.
RS-580i
TX-5
12 in.
Sand
10 in.

13. In-Box Cyclic Plate Load Tests
Cross-Section Complete Test Set-up
Experimental studies by different researchers indicated

14. Results of In-Box Paved Test Sections6 1 3 2
Testing Criteria: All sections will be loaded to ¾” rut depth. 4 5
Accumulated surface permanent deformation
10 in.
18 in.
6 in.
RS-580i
TX-5
12 in.
Sand
10 in.

15. Roller Compacted Concrete over Soil Cement under Accelerated Loading (completed)
Final report will be available soon.

16. Accelerated Load Testing Facility (ALF)
About 100-ft long, 40-ft wheel path,
Adjustable axle load: 9,750 lb to 18,950 lb
Nominal speed: 10.5 mph,
Wander covering 30’’ transverse distance.

17. Pre-rut Testing - Phase I
Section 1
Section 2
Section 3
Section 4
Section 5
Section 6