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Granular Base Stabilization with Emulsion in Las Vegas,
Nevada
Washington Avenue Rehabilitation Project
Todd Thomas, P.E. - Presenter
Authors Chris Finberg, City of Las Vegas
Department of Field Operations Dan Quire, Account Manager,
SemMaterials, L.P. Todd Thomas, Product Development
Engineer, SemMaterials, L.P.
Outline Purpose of the project Project description Existing conditions Laboratory evaluation Construction Observations Results
Purpose Provide structural capacity, saving
time and money relative to the alternative
Discuss technical aspects Discuss improvements
Project Limits
Rancho DriveM
artin
L. K
ing
Washington Ave.
0.8 Miles
Las Vegas, Nevada
Project Description2 Lanes in each direction, turn
lanes0.8 miles long (37,143 yd2)Mix of residential, small businesses,
a school and fire stationCurb and gutter15,500 AADT, 3% Trucks, TI = 9
Project DescriptionExisting asphalt was milled off in order
to stabilize the remaining aggregateHMA overlay over the emulsion-
stabilized base – match curb height
Existing PavementPavement Evaluation by Stantec
GPR – asphalt thicknessFWD – before and after
Existing SN = 3.0PQI = 6.5Layer Thickness
HMA: 4.5 to 7 inchesBase: 13.5 to 19.5 inches
Existing Pavement - BasePoorly graded sand or gravel with silty clay (fines PI of 6 or 7)Modified Proctor density of 145.2 pcf and OMC of 5.7%Passing No. 200 = 11.0%Material stabilized with asphalt emulsion – 5%
Existing PavementSubgrade
Symbol PI R-valueGC 28 18SM 9 35
CL-ML 7 13
ChallengesExisting base material was contaminated
– need for removalConventional design - remove and
replace18” agg base had to be removed18” of Type II had to be placedUtilities were 6” deep in the base
Construction Time (120 days) – Access and traffic delays
Asphalt Emulsion Provides flexibility and lower
susceptibility to cracking Binds the materials for improved
cohesion and strength Improved formulas that coat better
and build strength faster
Mix Design4, 5, 6, and 7% emulsion evaluated
5% used during construction4% water before mixing with emulsion
Superpave gyratory compactor – 150 mm mold, 30 gyrations
276,000 psi resilient modulus40 psi indirect tensile strength (dry)27 psi conditioned ITS
Construction Process
Construction Process
Construction Process
FDR Quality Control Moisture content Emulsion content Density Depth
Structural Comparison
6” HMA
18” Type II Aggregate Base
5.5” HMA
6” FDR
Total SN = 4.73 (from FWD)$925,685
Total SN = 4.50$1,248,346
7-12” existing Aggregate Base
Emulsion FDRTypical Reconstruction
Design SN = 4.35
FWD Results – Before and After
FDR AASHTO Layer Coefficient 0.28 per FWD testing. (HMA is typically 0.35 to 0.42)
Advantages
•$322,661 cost savings (30%)
•Construction time reduced from 120 to 40 days
•3,000 fewer loads of materials were trucked on and off the project
•Almost immediate traffic access to business
•Underground utilities weren’t affected
Chris Finberg (City of Las Vegas) – 702-236-4759
Dan Quire (SemMaterials, L.P.) – 303-915-2851
Todd Thomas (SemMaterials, L.P.) – 918-960-3828
Questions?