Pavements & Hardstand

Pavements and hardstand are the external trafficked surfaces of a site: car parks, driveways, loading and truck hardstand, service roads, footpaths and plazas. They are asphalt, concrete or segmental pavers over a base course and subgrade, with kerbs, edge restraints, line marking, wheel stops, and the drainage that keeps water out of the structure. Suspended car park decks are structure and have their own page; this page covers pavements on the ground.

Water is the main enemy of pavements: once it gets through cracks into the base and subgrade, the pavement loses support and fails under traffic. Drainage, crack sealing and resealing protect the investment far more cheaply than rebuilding.

What shortens life:

• Water entering cracks and saturating the base and subgrade.
• Heavy vehicles on pavements designed for cars, such as trucks, garbage trucks and cranes.
• Poor drainage and ponding.
• Tree roots lifting pavements and pavers.
• Deferred resealing, which lets asphalt oxidise and crack.

Asphalt ageing and cracking

Asphalt binder hardens and becomes brittle in sun and air. The surface greys and ravels, then cracks in blocks. Once cracks open, water enters and accelerates failure.

Fatigue (alligator) cracking

Interconnected cracking in wheel paths, like crocodile skin, means the pavement structure is failing under repeated loads, usually because the base is weak or wet. It cannot be fixed by surface treatment.

Rutting and shoving

Heavy or slow-moving loads, and soft asphalt in heat, push the surface into ruts and ripples, which hold water.

Potholes

Potholes form where water and traffic break out cracked asphalt and pump out base material. They grow quickly in wet weather.

Concrete pavement faults

Joints spall and lose sealant; panels crack across corners; panels settle and fault (step) at joints where the subgrade has softened or been pumped out.

Paver settlement and displacement

Pavers settle where bedding washes out or the base was inadequate; they rock, spread and lose joints where edge restraints fail; roots lift them; weeds grow in joints.

Trip hazards

Steps between slabs, lifted pavers, broken edges and potholes in pedestrian areas trip people, especially the elderly and people with impaired vision. Many public liability claims start here.

Edge and kerb failure

Unsupported pavement edges break away where vehicles run off them, and broken kerbs let edges crumble and water enter the base.

On site

• Greyed, ravelled asphalt; block cracking; alligator cracking in wheel paths.
• Potholes, patches, ruts and ponding after rain.
• Concrete panels cracked, spalled at joints, or stepped.
• Pavers rocking, sunken or lifted, with weeds and open joints.
• Trip edges on footpaths and around services pits.
• Faded line marking and missing wheel stops.
• Tree roots lifting surfaces.

In the records

• Pavement design and construction records.
• Resurfacing and resealing history.
• Trip and fall incident claims.
• Drainage drawings.

• Water ponding against kerbs and in low spots for hours after rain, showing where the base is being saturated.
• Patches of different ages and materials, recording where the pavement has failed before.

The pattern of cracking is the key to treatment: random block cracking across a whole area is age and can be sealed; cracking confined to wheel paths, truck turning areas and loading zones is structural and needs the base repaired; cracks along the line of a buried service or near a tree point to those causes.

Findings are graded by what they demand: safety (can hurt someone now), failure (failed and damaging the building), condition (distress present and progressing), lifecycle (renewal due on age and exposure), deadline (a regulator or ordinance sets the date), check (investigate before sizing works) and nil (cosmetic or stable).

A civil or pavement engineer for larger pavements; a building surveyor for small sites.

• Condition survey mapping distress types and extent, scored using a pavement condition index method so areas can be ranked and tracked.
• Trip hazard survey of pedestrian routes, measuring height differences.
• Cores and test pits to measure asphalt thickness, base quality and subgrade.
• Deflection testing on heavy-duty pavements to measure structural capacity.
• Drainage review: falls, pits, ponding and subsoil drains.
• Traffic review: vehicle types and loads now using the pavement.
• Accessibility check of accessible parking, kerb ramps and routes.

The report should give a condition map, priorities, recommended treatments by area, and a resurfacing programme.

Pedestrian trip surveys are best repeated annually on busy sites, so that hazards are found before they cause claims.

• Crack sealing to keep water out of sound pavements.
• Resealing asphalt with seal coats or thin overlays on a cycle.
• Patching: full-depth repair of failed areas, including base.
• Mill and overlay where the base is sound.
• Reconstruction where the base has failed, designed for current traffic.
• Concrete joint repair and panel replacement; slab lifting by grout.
• Relaying pavers with new bedding and edge restraints.
• Trip hazard removal by grinding, lifting or replacing.
• Drainage improvements.
• Line marking renewal.

• Kerb and edge repair with new edge restraints where pavements are breaking away.
• Heavy-duty sections rebuilt in concrete where trucks turn and stand, the zones that fail first in asphalt car parks.
• Permeable pavement maintenance: vacuum sweeping to restore infiltration.

Surveys are lump sums. Crack sealing is priced by length; resealing, overlays and reconstruction by area; patching by area and depth; pavers by area; line marking by length or per bay. Traffic management and night work in operating sites add cost.

Resealing and resurfacing are lifecycle on a cycle; patching and crack sealing are repairs and maintenance; trip hazards are immediate; accessibility rectification is code compliance.

Resurfacing in a busy car park is usually staged so parking remains available.

• Australia. Austroads guides cover pavement design and maintenance; AS 2890.1 covers parking facilities and AS 1428 access; councils and owners carry public liability for trip hazards, often using a threshold of around 20 millimetres for intervention.
• United Kingdom. BS 7533 covers paving with pavers and flags; highways authorities use intervention levels for trips; the Equality Act 2010 and Approved Document M set access; occupiers have duties under the Occupiers' Liability Acts.
• United States. ASTM D6433 sets the pavement condition index method; the 2010 ADA Standards set accessible routes and parking, including limits on changes in level; AASHTO guides pavement design.

In all three jurisdictions, owners and occupiers owe a duty of care to people using their pavements, and documented inspection and repair is the main defence to trip claims; strata and condominium car parks and driveways are typically common property.

• Pavement design and construction records.
• Resurfacing, resealing and repair history.
• Trip and fall incident and claim records.
• Drainage drawings.
• Traffic and vehicle use, especially heavy vehicles.
• Accessibility audit for external routes and parking.

• Trip hazard survey records and repair actions.
• Permeable pavement maintenance records where present.