Airport Pavement &
Aggregate Crushing
Presented by Kristen Blake, Shelby Brevogel, Lauren Hillis,
Nate Rahaim, and Andrew Short
Under the micromechanics of crushing by considering individual particle crushing strengths and triaxial shear tests on laboratory scale samples
Model the densification of the soil layers under airport pavements using the gyratory compactor and compare results to field compaction
Objectives
Leonards, 1995
Large Scale Versus Small Scale
Super Gyratory Compactor
Field Trafficking
versus
Past Work
Data acquisition from FAA testing facility
Effort to replicate data within the laboratory
Computations to create a comprehensible relationship
Current WorkConcentration on P-154
Energy Relation Determination
Density and Energy Calculations
•Energy based approach
•Reason being crushing in sub layers
Background
- When particles break, it will break into similar shapes as the original particle
- Higher coordination # will result in large particles breaking
McDowell (1996)
- Particles eventually reach a stable gradation, once the crushing of particles result in decreased volume
Coop (2004)
Equipment
•Skyscan 1072 micro-CT•Triaxial Compression Test
Particle Crushing
Concrete Sand in crushing Calcareous Sand in Crushing
Triaxial Compression Tests
Soil Properties
Sand Gs emax emin
D50 (inches)
Φ (degree
s)
Concrete 2.64 0.74 0.47 0.0270 34
Ottawa 2.65 0.86 0.5 0.0185 32.7Calcareous 2.73 1.014 0.77 0.0175 -
Soil Failures
50 60 70 80 90 100 110 120 130 1400
20
40
60
80
Ottawa Sand Stress Path
q' (psi)
p' (p
si)
10 15 20 25 30 3505
10152025
Ottawa Sand Stress Path
q' (psi)
p' (p
si)
Goals
Publish energy relation findings
Determine inherent soil properties and crushing characteristics for Calcareous Sands from Triaxial tests
Create Discrete Element Models of sand samples
Questions?