PFC5 Marshall Stability and Flow

Use this skill after a load-ready specimen exists. The PFC5 fistPkg dc.fis controller can provide a two-head setup/loading skeleton, but Marshall is not converted into a validated test merely by replacing planar platens, and it must not be interpreted as a Brazilian tensile-strength calculation.

When to use

• create or audit curved Marshall loading heads in PFC5;
• adapt a private fistPkg26 DiamCompTest working copy;
• extract load-deformation histories, peak load and edition-correct flow;
• compare PFC results against a laboratory Marshall test;
• diagnose wall IDs, axes, sign, head contact, smoothing or stopping logic.

Use pfc-asphalt-mixture for specimen generation and pfc5-asphalt-workflow for the complete case.

Required inputs

• PFC2D/PFC3D 5.0 and the unit system;
• legal <FISTPKG_ROOT> plus a passing dependency check/baseline run;
• governing standard edition, method ID and clauses;
• specimen dimensions, conditioning and test temperature;
• head geometry/radius/width and PFC5-compatible wall representation;
• prescribed loading rate/control mode and stop condition;
• head-particle contact properties and friction;
• definition/correction procedure for stability and flow;
• laboratory curve/targets, tolerances and desired crack/failure outputs.

For current work use JTG 3410-2025 T 0709-2025, effective 2025-10-01, and trace the specimen to the selected T 0702-2025 forming route. JTG E20-2011 T0709 is retained only for declared legacy reproduction. Do not mix current curve correction/reporting rules with legacy apparatus or conditioning values.

Audited fistPkg26 contract

The inspected dc.fis:

• calls _dcMakeWalls during dcSetupPhase;
• expects head pointers dcWp0 and dcWp1, normally found from wall IDs 1 and 2;
• uses the second coordinate as axial position/velocity;
• initializes wall-force and wall-strain callbacks;
• can stop after force falls to a fraction of the recorded peak.

_dcMakeWalls is the minimum geometry hook. A complete adapter must also verify:

1. wall IDs/pointers and head initial gap;
2. curved-facet orientation, head translation and prohibited rotations;
3. PFC5 wall import/generation syntax;
4. current and future grain-head contact laws;
5. suitability of ft_SmoothGrainWallInterface;
6. force, displacement and sign conventions in 2D/3D;
7. peak capture, sampling rate and post-peak termination;
8. edition-specific flow correction and unit conversion.

Workflow

1. Run the unmodified fistPkg DiamCompTest baseline in a PFC5.0 runtime.
2. Copy the project privately and preserve an upstream/change manifest.
3. Replace the planar-head construction through a separately documented override.
4. Run a no-particle/head-motion probe, then a small-particle contact probe.
5. Install the actual specimen, remove unintended overlap without altering the intended fabric, equilibrate and save the pre-load state.
6. Initialize independent reaction-force and head-separation/displacement histories. PFC5 wall.force.contact is the global-coordinate sum of contact forces acting on each wall; keep both heads and verify their equal/opposite balance before deriving a scalar load. Set a displacement reference explicitly because wall.disp is an accumulated wall displacement and is writable.
7. Load at the edition-specific rate; retain enough post-peak data for the selected stop and flow procedure.
8. Preserve the raw curve, apply the selected edition's origin correction, and branch explicitly when the peak is not obvious; never replace the current correction with raw peak displacement or a fixed post-peak fraction.
9. Compare the full curve, peak/flow and failure pattern against laboratory data and run seed/resolution/rate sensitivity.

Working rules

• Keep all case commands PFC5-pure; newer geometry/FISH syntax requires an explicit port.
• Do not claim dc_wfa/dc_wda automatically equal final normative stability/flow; independently audit sign, units, sampling and correction.
• Do not add the signed forces from two opposed heads and call the cancellation a specimen load. Resolve both forces on the declared loading axis, compare magnitudes, and state the scalar-load convention.
• Treat dry stability, immersed stability and vacuum-saturation stability as distinct protocols. A dry DEM solve cannot be relabeled as water sensitivity.
• Do not claim that _dcMakeWalls is the only required change.
• Keep setup, equilibrated pre-load and loaded milestone saves.
• If the standard text or runtime is unavailable, deliver the raw curve and mark the normative result/runtime gate pending.

Output contract

• PFC2D/PFC3D 5.0, units, standard edition/method/clause and source manifest;
• specimen/head geometry and audited PFC5 head construction;
• wall/contact/control/stop parameter tables;
• baseline, no-particle and contact-probe results;
• load-deformation history, raw peak load/displacement and standard-corrected metrics;
• equilibrium and sensitivity evidence;
• laboratory validation and runtime_validated status.

Local contents

• references/overview.md — legacy fistPkg dc.fis parameters and adapter notes.
• references/jtg-t0709-note.md — legacy 2011 checklist; not a current numeric source.
• references/jtg-3410-2025-t0709.md — current method chain, raw/corrected curve contract and PFC5 mapping.
• ../pfc5-asphalt-workflow/references/standards-policy.md — current/legacy policy.
• scripts/marshall_head_contact_pilot.p3dat — executable curved-head PFC3D 5.0 contact pilot; not a normative Marshall model.
• dependencies.json — package-level sibling-skill assets required for the complete workflow.
• agents/openai.yaml — Agent metadata.