innovative uses for rap in road construction and repair
TRANSCRIPT
Innovative Uses for RAP in Road Construction and Repair
Amanda Hufft
Outline
• RAP Availability• FDOT’s Research
RAP in Florida: A Call for Innovation
Introduction to ReCharge™
• 100% RAP Surface Paving• 100% RAP Base Construction• Pothole Patching
Construction of Cold Mixtures
Outline
RAP Availability
February 25, 20213
→ Reported tonnage of stockpiled RAP represents roughly 1½ years of inventory nationwide
→ About 94% producers reported having stockpiled RAP
NAPA’s Asphalt Pavement Industry Survey on Recycled Materials & WMA Usage (2019)
What can you do with a surplus of RAP??>>
High RAP Asphalt Mixes forLow Volume Roads
BACKGROUND
→ 1.8 million tons of RAP produced each year from FDOT yearly maintenance and rehabilitation
→ Agency representatives expressed interest in economical solutions for:→ Paving unpaved roads→ Resurfacing existing low volume roads
February 25, 20214
BE 194 (FDOT and TTI, Nov. 2018)
High RAP Asphalt Mixes forLow Volume Roads
February 25, 20215
BE 194 (FDOT and TTI, Nov. 2018)
21,780
84,320 106,100
14,728
1,563 16,291
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Rural36,508 mi
Urban85,883 mi
Total122,391 mi
Mile
s
Paved and Unpaved Proportions forRural and Urban Roadways in Florida
(Table HM-51, FHWA 2014)
UnpavedRoadsPavedRoads
Length by Functional System with Less than 1,000 ADT in Florida
(Table HM-57, FHWA 2014)
Functional System Rural Urban Total % ADT
< 1,000 (mi) (mi) (mi) Principal Arterials 20 --- 20 0.3 Minor Arterial 105 14 119 1.9 Major Collector 1,210 232 1,442 13.8 Minor Collector --- 118 118 2.3 Total (mi) 1,336 363 1,699 % of Total Length 3.7 0.4 1.4
COMMON DRAWBACKS OF UNPAVED ROADS→ Require frequent maintenance
→ Higher risk of rutting and washboarding
→ Requires routine dust control treatments
Cold Recycled Mixtures
February 25, 20216
→ Cost comparison indicated savings of 20-50% with cold recycling
→ LCCA concluded the most favorable option was 100% RAP foamed cold recycled mixture
→ Cold recycled mixtures generally did not meet strength requirements and experience accelerated rutting at early load cycles
Conserve Resources
Low Cost(40-50% less than other methods)
Ease of Use(commonly used with emulsified or foamed asphalt)
BE 194 CONCLUSIONS
ReCharge™ — An advanced cold mix additiveReCharge™ allows for easy blending, spreading, and compaction of 100% RAP material by activating the aged binder on the surface of RAP withoutheat and no additional asphalt.
→ Allows for resurfacing dirt roads at minimal cost
→ Ideal for cold-mix/pothole and patch repairs
→ Job site mixing or off-site pre-mixing
→ No special equipment required
→ Remains workable for several hours
→ Allows traffic within hours of construction
February 25, 20217
KEY BENEFITS
ReCharge™ — Laboratory Study
SPECIMEN PREPARATION
→ Dose RAP with ReCharge™ and compact to 150 gyrations
→ Place specimen in front of fan for 30 minutes
→ Cure in 60°C oven for 48 or 72 hours
February 25, 20218
Laboratory Study on Curing
2378
2800
Min. 1,250lbtested @ 40°C
0 1 2 3 4
0
500
1000
1500
2000
2500
3000
48 72
Mar
shal
l Sta
bilit
y (lb
)
Curing Time @ 60°C (hr)
Marshall Stability vs. Curing Time @ 60°C
100% RAP Cold Mix — Surface PavingPROJECT OVERVIEW
February 25, 20219
Location: Gulf Point Rd, Santa Rosa Beach, FL
Traffic: residential road with mostly car traffic
Objective: pave a 100% RAP road using existing RAP stockpileon top of an existing RAP aggregate base
Construction Dates: 07/31/19 to 08/02/19
100% RAP Cold Mix — Surface Paving
February 25, 202110
Additive Dosing
Mixture Blending Final Product
MIXPRODUCTIONSanta Rosa Beach, FL
100% RAP Cold Mix — Surface Paving
February 25, 202111
CONSTRUCTIONSanta Rosa Beach, FL
100% RAP Cold Mix — Surface PavingINITIAL PERFORMANCE
→ Cars were able to drive on roadway within minutes of compaction
→ No visible signs of rutting
→ Hardness comparable to HMA after placement
→ No significant tenderness→ Edge compaction is crucial to performance
February 25, 202112
Santa Rosa Beach, FL – 08/02/19
100% RAP Cold Mix — Surface PavingFIELD SURVEY – 02/12/20
→ Ride quality: light vibrations with no speed reduction necessary
→ No rutting or cracking
→ Some weathering and raveling mostly along edges
February 25, 202113
Santa Rosa Beach, FL – 02/14/21
100% RAP Cold Mix — Base ConstructionPROJECT OVERVIEW
February 25, 202114
Location: Riverview Park Rd, Hannibal, MO
Traffic: park road leading to a water treatment plant, low traffic
Objective: mill existing over-crowned asphalt pavement and usemilled RAP to create a stable base for an asphalt overlay
Construction Dates: 09/29/20 and 10/01/20
100% RAP Cold Mix — Base Construction
February 25, 202115
MIX PRODUCTIONHannibal, MO
100% RAP Cold Mix — Base Construction
February 25, 202116
BASE CONSTRUCTIONHannibal, MO
Spreading Mix
Compaction
Finished Product
100% RAP Cold Mix — Base Construction
February 25, 202117
OVERLAY PAVINGHannibal, MO
100% RAP Cold Mix — Pothole PatchingPROJECT OVERVIEW
February 25, 202118
Location: City of Ridgeland, MS
Traffic: all city roads with varying traffic
Objective: use existing RAP stockpile to patch potholes on cityowned roads
Construction Dates: Ongoing since early 2020
100% RAP Cold Mix — Pothole PatchingMIX PRODUCTIONCity of Ridgeland, MS
February 25, 202119
100% RAP Cold Mix — Pothole Patching
February 25, 202120
POTHOLE PATCHINGCity of Ridgeland, MS
References
February 25, 202121
→ Arambula-Mercado, E., Chavarro-Munoz, S.J., Hu, S., Epps, J., Sug Park, E., and Epps Martin, A. (2018). High Reclaimed Asphalt Pavement (RAP) Asphalt Mixes for Low Volume Roads. Florida Department of Transportation, Tallahassee, FL.
→ Cox, B.C. and Howard, I.L. (2015). Cold In-Place Recycling Characterization Framework and Design Guidance for Single or Multiple Component Binder Systems. Report No. FHWA/MS-DOT-RD-15-250 Vol. 2, Mississippi Department of Transportation, Jackson, MS.
→ Williams, B.A., Willis, J.R., and Shacat, J. (2020). Asphalt Pavement Industry Survey on Recycled Materials and Warm-mix Asphalt Usage: 2019. Information Series 138 (9th
edition). Federal Highway Administration, Washington, DC.
Questions?