Parked decks and ramps carry heavy vehicle loads, rubber tire transfer, oil and fuel spills, and wet cleaning under turning and braking traffic. Polished concrete handles this traffic, but the finish must be scoped around slope, drainage and slip risk, not copied from a showroom spec. This guide covers base-condition judgment, spill handling, wet-state slip ratings, joint details and acceptance clauses for the PM and owner representative.

What Parking Traffic Demands From a Polished Slab

A parking slab sees repeated static loads from cars and light vans, plus wheel loads on tires and cart casters. The finish does not carry this load; the slab does. Wear comes from tire scrub in turns and brakes, doors and dragged equipment. Stains build from leaked oil, grease, fuel and coolant; densification and seal choice decide whether a spill releases with neutral detergent or etches the paste. Densifier and sealer add abrasion resistance, not structural capacity.

Base Survey: Age, Moisture, Joints and Existing Wear

Before grinding, survey the slab on a parking-level plan. A new slab should cure at least 28 days before densification; in-situ RH below 75 to 80 percent, surface temperature 10 to 30 degrees Celsius. Flag spalling, hollow zones, prior patches and moving cracks for repair before the finish pass. Mark saw-cut, expansion and construction joints, noting open or degraded fills that trap dirt and catch casters.

Vehicle Loads, Tire Marks and Rubber Staining on Decks and Ramps

Vehicle load spreads over the tire contact patch, but turns and brakes concentrate scrub into a small patch that wears the paste and leaves rubber transfer. Black tire marks build fastest at ramp entrances, stop lines and turning circles. A densified sealed slab releases them with neutral cleaner and damp mop; an under-densified slab absorbs rubber and oil, leaving a permanent gray patch after sealing.

Slope Geometry and Wet-State Slip Ratings

Parking slip testing separates dry walking surfaces from wet ramp and runoff zones. In dry decks and walkways, a pendulum PTV of at least 36 is the usual target. On ramps where washdown persists, wet PTV reads 10 to 20 points below dry, so the wet measurement governs the spec. DCOF stays at or above 0.42 in wet ramp zones, and R10 to R12 classes grade traction on slopes and circles. Test after sealer cure at the same dry and wet points; a low wet reading calls for finer grit or treatment.

Oil, Grease and Fuel Spill Removal Before and After Polishing

Existing oil and grease must be cleaned before grinding, because hydrocarbons glaze resin pads and stop densifier wetting the paste. Sweep loose dirt, apply matched degreaser, scrub and rinse until water clears. After polishing, damp-mop with neutral detergent pH 6 to 9, rinse spills within 15 minutes, avoid acids or abrasive pads. Sealer reduces future uptake but does not remove an existing deep stain; re-coat every 3 to 5 years in decks, 2 to 3 years in ramps.

Drainage, Joints and Edge Details on Ramps and Turning Lanes

Polished parking floors depend on the slab falling to drains and channels, not the finish itself. Check ramp runs drain to the low edge and no standing water collects at slope breaks or thresholds. Joints must be filled flush or sealed with flexible material so tires and casters do not catch an open gap. At walls, curbs and grates, grind the perimeter back and seal joints to adjacent material.

Grit Sequence, Densifier and Finish Targets for Parking Zones

A standard run opens with metal-bond diamonds at 16, 20, 30 and 40 grit to level joints, spalling and patches, then resin pads at 100, 200, 400 and 800 grit toward the chosen sheen; skip a grit only when scratches are gone. Densifier goes on after 40 to 100 grit, at 1:64 or about 15 ml per liter. On ramps and lanes, stop at matte to satin rather than mirror gloss. Check sheen with a 60 degree gloss meter at 2 to 3 m spacing; bays differ by up to 5 units, over 15 units means rework.

Acceptance Walkthrough, Defect Limits and Handover to the Operator

Most handover disputes come from unstated expectations: sheen level, wet ramp slip rating, joint treatment and stain resistance are assumed but never written into the spec. Close the job with a documented walkthrough by zone: gloss readings, dry and wet PTV or DCOF results, joint and drain photos, and the maintenance schedule signed by the owner representative.

1. Verify slab age over 28 days, RH below 75 to 80 percent, soundness and joint condition before grinding.
2. Record vehicle classes per zone and confirm slab thickness and reinforcement against the structural drawing.
3. Measure dry PTV at least 36 and wet PTV or DCOF at or above 0.42 on every ramp and runoff zone after seal cure.
4. Clean existing oil and grease to a clear rinse before grinding; re-check repellent patches before the seal pass.
5. Check joint fill flush, drain fall and edge sealing along walls, curbs and grate transitions.
6. Hand over the sealer re-coat interval, 3 to 5 years general and 2 to 3 years ramps, and the pH cleaning limits.

When base conditions, loads, slip ratings and drainage details are agreed in writing before the grind, the finish behaves predictably under traffic, and disputes stay limited to touch-ups. The contractor's role is to judge what the slab can carry, lock zone targets into the spec, and deliver acceptance measurements the owner representative signs without qualification.