--- name: pfc-rutting-test description: Design, implement, and audit PFC3D 5.0 asphalt wheel-tracking/rutting simulations using RVE-to-strip-to-full-size scaling, PFC5-compatible wall motion and reaction-force control, Burger-calibrated contacts, rut-depth histories, edition-specific dynamic-stability calculations, and explicit equivalent-load validation. ---

# PFC5 Wheel-Tracking and Rutting Test

Use this skill after specimen generation and Burger calibration. Prefer PFC3D because wheel width, lateral confinement, contact patch and rut geometry are intrinsically three-dimensional.

## When to use

- plan a wheel-tracking/rutting model in PFC 5.0; - choose a moving, rolling-faceted or fixed equivalent cyclic load; - servo a wall/head to a target reaction rather than assign a read-only contact force; - extract rut-depth histories and an edition-specific dynamic-stability metric; - scale an RVE to a strip/pilot and then a full-size slab.

Do not use this skill for Marshall or for specimen generation.

## Required inputs

- exact PFC3D 5.0 build, units and runtime budget; - governing standard edition, method ID, clauses and machine/specimen coefficients; - slab, mold, wheel and travel geometry; - conditioning/test temperature; - wheel motion definition and whether “count” means one-way pass or complete cycle; - prescribed pressure/load and the physical/equivalent contact-area definition; - load-control implementation and tolerance; - load-ready specimen plus calibrated contact parameters; - rut-depth measurement region/reference and stop condition; - laboratory rut curve/dynamic-stability targets.

The current reviewed route is JTG 3410-2025 T 0719-2025, effective 2025-10-01. JTG E20-2011 T0719 is a legacy route and must not supply current default dimensions, time windows or coefficients.

## Modeling hierarchy

1. **RVE/material check** — calibrate creep/recovery and timestep sensitivity. 2. **Strip/pilot model** — verify boundaries, contact patch, load servo, wheel motion, rut measurement and computational cost. 3. **Full-size model** — use only after the first two gates pass.

The exact dimensions and test values come from the selected standard edition or laboratory protocol, not from a remembered default.

## Loading routes

| Route | Meaning | Acceptance gate | | --- | --- | --- | | moving faceted wheel/head | translation over slab | reaction and footprint match target throughout travel | | rolling faceted wheel | translation plus angular velocity | kinematic sign, slip and facet-resolution sensitivity | | fixed equivalent cyclic patch | accelerated surrogate | correlation to moving-wheel pilot; never label as normative motion |

In PFC5, contact force is normally an observed reaction. Apply load by a verified servo or velocity/position control and demonstrate that the reaction meets the target. Pressure-to-force conversion requires a declared reference area; the evolving DEM contact area is not automatically that area.

## Workflow

1. Freeze standard edition, physical parameters and numerical equivalents separately. 2. Restore the load-ready specimen, audit boundaries/contact groups and equilibrate. 3. Build and motion-test the wheel/head with no specimen. 4. Run a small contact/load-servo probe; quantify reaction error and oscillation. 5. Run the strip pilot for a short declared number of cycles/passes. 6. Record wheel position, commanded motion, reaction, reference surface, rut depth, the seven fixed-position measurements or an approved equivalent, timestep, equilibrium/inertia indicators, one-way pass count and round-trip count. 7. Confirm no wall penetration, particle escape, axis/sign error or callback duplication. 8. Run the production duration with restart saves. 9. Compute the standard metric only from the selected edition's formula, intervals and coefficients; otherwise report the raw rut history with the metric pending. 10. Compare against laboratory curves and run seed/resolution/rate/load-route sensitivity.

## Working rules

- Keep PFC5 command/FISH syntax version-pure. - Do not set `wall.force` as if it were a prescribed actuator without proof from the exact PFC5 API; use a verified motion/servo controller. - Do not assume a rectangular patch, accelerated cycle or fixed load is equivalent to a moving rubber wheel. Calibrate and label the surrogate. - For T 0719-2025, compute DS from the current method's pass-count interval and width coefficient. Do not use the legacy `45 min/60 min` shorthand or an unverified extra correction coefficient. - Preserve RVE, strip, pre-load, pilot and production milestone saves. - Full-size output without pilot load-control evidence is not validated.

## Output contract

- PFC build/units and standard edition/method/clause; - physical versus DEM-equivalent parameter table; - specimen/wheel/boundary/contact assignment; - actuator/servo pseudocode or PFC5-verified code plus reaction-error history; - rut-depth measurement definition and raw time/pass/cycle history; - edition-correct metric calculation with units/coefficients, or pending status; - RVE/strip/full-size stage evidence and sensitivity results; - laboratory comparison and `runtime_validated` status.

## Local contents

- `references/overview.md` — current T 0719-2025 measurement, count and PFC3D mapping. - `references/jtg-t0719.md` — current-version gate, user-input template and symbolic metric; no standard data tables. - `references/modeling-strategy.md` — PFC5-safe hierarchy and controller pseudocode. - `../pfc5-asphalt-workflow/references/standards-policy.md` — standards policy. - `scripts/rutting_contact_pilot.p3dat` — executable curved-wheel PFC3D 5.0 contact/translation pilot; not a normative wheel-tracking model. - `dependencies.json` — package-level sibling-skill assets required for the complete workflow. - `agents/openai.yaml` — Agent metadata.