Stability Criteria

Marshall stability, flow, and quotient limits by traffic level per ASTM D6927 / AASHTO T245

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Marshall Design Criteria

Performance thresholds for stability, flow, and stiffness quotient

Heavy Traffic (≥ 10M ESALs)
Stability (min)≥ 8.0 kN (1800 lbf)
Flow2 - 4 mm (8-16 units)
MQ (Stability/Flow)≥ 2.5 kN/mm
Air Voids3% - 5%
VMA (min)> 13%
TSR (AASHTO T283)≥ 80%
Medium Traffic (1M - 10M ESALs)
Stability (min)≥ 5.3 kN (1200 lbf)
Flow2 - 4 mm (8-16 units)
MQ (Stability/Flow)≥ 1.8 kN/mm
Air Voids3% - 5%
VMA (min)> 13%
TSR (AASHTO T283)≥ 75%
Light Traffic (< 1M ESALs)
Stability (min)≥ 3.3 kN (750 lbf)
Flow2 - 4 mm (8-16 units)
MQ (Stability/Flow)≥ 1.2 kN/mm
Air Voids3% - 5%
VMA (min)> 13%
TSR (AASHTO T283)≥ 70%
Key Formulas
Stability = Pmax × Cthickness
Flow = Deformation at Pmax (0.25 mm units)
MQ = Stability / Flow (kN/mm or lbf/0.01in)
Air Voids = 100 × (1 - Gmb / Gmm)
VMA = 100 - (Gmb × Ps / Gsb)
VFB = VMA - Air Voids
Pmax = maximum load • Cthickness = thickness correction factor (1.0 for 63.5mm) • Gmb = bulk specific gravity • Gmm = theoretical max specific gravity • Ps = aggregate % by weight • Gsb = aggregate bulk specific gravity
Traffic Classification & Criteria
Traffic Level ESALs (Design Life) Min Stability (kN) Flow Range (mm) Min MQ (kN/mm) Min TSR
Very Heavy> 30M10.02-33.085%
Heavy10M - 30M8.02-42.580%
Medium1M - 10M5.32-41.875%
Light0.1M - 1M3.32-41.270%
Very Light< 0.1M2.22-40.865%
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