Adelaide & South Australia

Pavement Design & Investigation Services, Adelaide

Understand the Subgrade, Design for the Load, and Build for Long-Term Performance

Pavement performance depends on more than the surface you drive on. Traffic loading, pavement thickness, material quality, subgrade strength, and moisture conditions all influence how a pavement performs over its design life. Our pavement material testing and design services assess these factors before construction to help reduce premature cracking, deformation, and costly remediation across Adelaide and South Australia.

Talk to Our Experts
  • 50+ Years Combined Experience
  • ISO Certified Management Systems
  • Engineers Australia Members
  • Australian Geomechanics Society Affiliates
  • Testing Undertaken by NATA-Accredited Laboratories Where Required

What Is Pavement Design & Investigation?

Characterising Subgrade Conditions and Designing Pavement Structures to Suit

Pavement design is the process of determining the pavement structure, which includes type, thickness, and material specification, required to carry the anticipated traffic loading over the design life without unacceptable deformation or deterioration.

A pavement must provide a safe and functional surface with appropriate drainage, durability, and riding quality throughout its service life. Pavement investigation is the geotechnical assessment that underpins the design, establishing the subgrade conditions, material properties, and moisture environment the pavement will be built on and must perform in.

Across Adelaide, pavement investigations may encounter reactive clay, variable fill, residual soils, and weathered rock. These conditions cause significant differences in subgrade strength, moisture response, and pavement support across a site, making appropriate investigation important before finalising pavement thickness and materials.

At BHM Geotechnical, our pavement investigation and pavement design services include:

Geotechnical investigation specifically scoped for pavement design purposes
Subgrade characterisation including CBR testing, moisture content, and plasticity assessment
Pavement material testing including soaked CBR, shrink-swell index, and gradation analysis
Reactive subgrade identification and subgrade treatment design in accordance with Department for Infrastructure and Transport (DIT) EW100 (Earthwork for Roads).
Flexible pavement design using Austroads Guide to Pavement Technology methodology
Rigid pavement design for high-load applications including concrete hardstands and industrial areas
Pavement investigation for distressed roads and carparks to establish the cause of premature failure
Reporting to support development approval, council requirements, and construction documentation

These services support residential subdivision, commercial development, industrial hardstands, road upgrades, and civil infrastructure projects across South Australia.

Pavement Design Services

Aligning Pavement Structure to Subgrade Conditions for Reliable Performance

A pavement acts as an engineered structure to spread wheel loads to the subgrade and provide a functional riding surface with proper drainage, skid resistance, and durability. Performance depends on matching the pavement structure to the underlying conditions.

01

Flexible Pavement Design

Flexible pavements are the most common road construction type across Adelaide’s metropolitan area and suburban growth corridors.

Our flexible pavement design services typically include

  • Subgrade CBR assessment and design subgrade CBR determination
  • Reactive subgrade evaluation including shrink-swell index testing and capping layer design
  • Empirical flexible pavement design using Austroads Guide to Pavement Technology Part 2
  • Mechanistic design for bound and full-depth asphalt pavements using elastic layer modelling
  • Pavement layer thickness and material specification for wearing course, base, subbase, and subgrade treatment
  • Review of design against Austroads & South Australian Requirements where applicable

Flexible pavements distribute wheel loads through the surface, base, and subbase before transferring them to the subgrade. The strength and behaviour of each layer and the underlying ground determine overall performance.

02

Rigid Pavement Design

Rigid concrete pavements are used where load requirements, traffic volumes, or operational demands exceed what a flexible pavement can reliably provide.

Our rigid pavement design services typically include

  • Subbase assessment and design for concrete pavement support conditions
  • Jointed unreinforced, jointed reinforced, and continuously reinforced concrete pavement design
  • Slab thickness design and joint spacing determination for the anticipated loading and subgrade conditions
  • Steel fibre reinforced concrete pavement assessment for industrial and heavy-duty applications
  • Specification of joint sealing and drainage provisions to protect subbase and subgrade from moisture
  • Review of design against relevant Australian Standards and project-specific performance criteria

Rigid pavements rely on the concrete slab to spread wheel loads over a wider subgrade area. Design considers slab strength and thickness, subbase support, jointing, drainage, and ground conditions.

03

Pavement & Subgrade Investigation

A pavement investigation establishes the subgrade conditions, existing pavement structure, and material properties that the design must account for.

Our pavement investigations typically include

  • Test pit excavation and DCP testing to characterise subgrade conditions and existing pavement structure
  • Subgrade sampling and laboratory pavement material testing including CBR, plasticity, and shrink-swell index
  • Assessment of in-situ moisture conditions and seasonal moisture variation relative to pavement equilibrium
  • Identification of contaminated, uncontrolled, or reactive fill requiring treatment or removal
  • Distress investigation for failed pavements to identify the cause of premature failure
  • Reporting of investigation findings in a format directly usable for pavement design

Pavement investigations across Adelaide’s outer growth corridors often encounter uncontrolled fill and highly variable residual soil profiles that significantly affect subgrade design CBR values, making targeted investigation essential before deciding pavement thickness.

04

When Do You Need Pavement Investigation or Design?

Common Project & Site Conditions Requiring Pavement Engineering Input

  • New road construction for residential subdivisions or commercial developments requiring pavement design to meet council standards
  • Industrial hardstand and carpark construction where load requirements and traffic patterns need to be matched to a specific pavement structure
  • Road upgrade or rehabilitation projects where existing subgrade conditions need to be reassessed before a new pavement structure is designed
  • Sites with known or suspected reactive clay subgrades requiring subgrade treatment design in accordance with DTI EW100
  • Development applications requiring pavement design documentation as a condition of approval
  • Distressed pavements showing premature cracking, rutting, or shape loss where the cause needs to be identified before remediation is designed
  • Fill sites or former industrial land where subgrade conditions are uncertain and require investigation before pavement construction
  • Import or reuse of pavement materials requiring testing to confirm compliance with specification requirements

Addressing pavement investigation and design before construction is consistently less costly than remediating a failed pavement during its design life.

Plan Your Pavement From the Ground Up

Connect With Adelaide’s Pavement Material Testing & Design Team

We provide pavement investigation, pavement material testing, and pavement design services for projects in Adelaide and SA region.

    Why Choose BHM Geotechnical?

    Geotechnical Investigation & Pavement Design Under One Team

    50+ Years Combined Experience

    BHM Geotechnical brings geotechnical engineering expertise, NATA-accredited laboratory testing, and direct experience of the subgrade conditions that govern pavement performance across Adelaide and South Australia.

    Our pavement investigations and designs are grounded in the actual subgrade conditions present on each site. We address reactive clay and variable fill conditions from the outset, preventing costly pavement distress later.

    Geotechnical Engineering Expertise

    Pavement investigations and designs led by qualified geotechnical engineers experienced with Adelaide’s reactive clay subgrades, variable fill profiles, and residual soil conditions.

    NATA-Accredited Laboratory Testing

    Subgrade and pavement material samples tested by NATA-accredited laboratories for CBR, shrink-swell index, plasticity, gradation, and other parameters required for design.

    Austroads and DTI Compliance

    Pavement designs prepared in accordance with the Austroads Guide to Pavement Technology and DTI South Australia standards applicable to the project type.

    Reactive Subgrade Experience

    Practical experience designing pavements on Adelaide’s reactive clay subgrades, including capping layer specification and subgrade treatment design to manage moisture-driven volume change.

    Responsive Project Delivery

    Investigation, testing, and design completed efficiently to keep subdivision, development, and civil construction programmes on track.

    Pavement Design for Roads, Hardstands & Developments

    Engineering Pavements Around Their Actual Loads & Ground Conditions

    The consequences of an under-designed or poorly investigated pavement show up quickly under traffic loading. Our services support:

    01

    Residential Subdivision Roads

    Design subdivision roads to meet council standards with pavement structures suited to the reactive clay and variable fill subgrades common across Adelaide’s growth corridors.

    02

    Commercial & Industrial Hardstands

    Specify flexible or rigid pavement structures for carparks, loading docks, and hardstands based on actual wheel loads and subgrade conditions. This approach avoids reliance on generic assumptions.

    03

    Road Upgrade & Rehabilitation

    Assess existing subgrade and pavement conditions before specifying a rehabilitation treatment. This process addresses the underlying issues that caused the original pavement to fail.

    04

    Distressed Pavement Investigation

    Identify the cause of premature cracking, rutting, or shape loss in an existing pavement and provide a design basis for remediation that addresses the root cause.

    05

    Fill Site Development

    Characterise uncontrolled or variable fill subgrades on former industrial or undeveloped land before pavement construction. This ensures pavement designs are properly matched to the fill’s support capacity.

    06

    Development Approvals

    Provide pavement design documentation to satisfy council or authority conditions requiring design compliance with Austroads or DTI standards.

    Could the Subgrade Compromise Your Pavement Design?

    Ground Conditions Worth Investigating Before Design Is Finalised

    Not every pavement problem is obvious before construction. A site with reactive clay near subgrade level, uncontrolled fill of unknown origin or depth, variable soil conditions across the pavement footprint, or a history of nearby pavement failures can indicate that a targeted investigation is needed before finalising design.

    In Adelaide, the prevalence of Hindmarsh Clay across the southern and western metropolitan area means reactive subgrade conditions exist on many sites that do not appear problematic from surface observation alone.

    Investigation and pavement material testing before design ensures geotechnical input delivers the most value, avoiding surprises during construction.

    The Pavement Design Process

    How We Turn Ground Conditions & Traffic Requirements Into a Pavement Structure

    01

    Site Review & Scope Definition

    Review project requirements, intended pavement use, design traffic loading, and available site information to define the investigation scope and applicable design standard.

    02

    Subgrade Investigation

    Carry out test pit excavation and DCP testing to characterise subgrade conditions across the pavement footprint and collect samples for laboratory testing.

    03

    Pavement Material Testing

    Submit subgrade and pavement material samples to a NATA-accredited laboratory for CBR, shrink-swell index, plasticity, and other pavement material testing required for design input.

    04

    Design Subgrade Assessment

    Determine the design subgrade CBR and assess subgrade reactivity, identifying treatment requirements for reactive or weak subgrade materials before pavement layers are specified.

    05

    Pavement Structure Design & Reporting

    Design the pavement structure according to Austroads and South Australian (DTI) requirements, specifying layer thicknesses and materials. Prepare a report documenting investigation findings, design inputs, and pavement specifications.

    Design for Long-Term Pavement Performance

    Reduce Premature Failure by Getting the Ground, Materials & Structure Right

    Prevent Premature Pavement Failure

    Insufficient subgrade characterisation often results in under-specified pavements that crack and deform well before their intended design life.

    Address Reactive Subgrade Conditions

    Adelaide’s reactive clay subgrades need targeted design treatment to control moisture-driven volume change. Identifying and addressing these conditions before construction prevents cracking and distress.

    Meet Council and Authority Standards

    Residential subdivision and commercial development roads must meet council and DTI standards for pavement design and material specification; documented investigation and design provides the evidence base for compliance.

    Reduce Long-Term Maintenance Costs

    Pavements designed for actual subgrade conditions and traffic loading outperform generic designs and lower long-term maintenance and rehabilitation costs.

    Support Cost-Effective Material Decisions

    Pavement material testing of existing site materials confirms if they can be reused in the pavement structure, potentially reducing import costs and disposal needs.

    Provide a Basis for Remediation When Failure Has Occurred

    A distressed pavement investigation identifies the cause of failure, such as reactive subgrade, inadequate thickness, or poor drainage. This provides a design basis for remediation that targets the root cause and achieves long-term performance.

    Explore Related Services

    Related Geotechnical & Environmental Services

    Geotechnical Site Investigations

    Characterise soil and rock conditions through drilling, test pits, sampling, and laboratory testing to inform pavement and foundation design.

    Bearing Capacity Assessment (DCP/PSP)

    Assess in-situ subgrade bearing capacity using dynamic cone penetrometer and plate load testing to support pavement and foundation design.

    Site Classifications

    Classify sites for footing design in accordance with AS 2870, including assessment of reactive soil conditions relevant to pavement subgrade behaviour.

    Compaction & Earthworks

    Provide specifications and testing for compaction of pavement subgrade, capping layers, and fill material to support pavement construction quality.

    Preliminary Site Investigations (PSI)

    Identify historical land use and contamination concerns on former industrial or undeveloped sites before pavement construction commences.

    Salinity & Aggressivity Assessments

    Assess soil and groundwater aggressivity to concrete and steel to inform pavement subbase and drainage structure material selection.

    Trusted for Pavement Design Across Adelaide

    BHM Geotechnical supports developers, road authorities, civil contractors, and councils with reliable pavement investigation, material testing, and design services throughout Adelaide and South Australia.

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    Efficient, concise geotechnical engineering advice.
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    Design Your Pavement on What the Ground Actually Contains

    We help you establish the subgrade conditions, material properties, and structural requirements needed to design for expected traffic loads and long-term performance.

    Get a Custom Solution
    FAQs

    Frequently Asked Questions

    What is the difference between flexible and rigid pavements?

    Flexible pavements distribute wheel loads through layered surface, base and subbase materials, while rigid pavements use concrete slab action to spread loads over the subgrade. The appropriate pavement type depends on traffic loading, ground conditions, performance requirements and project constraints.

    What is pavement material testing?

    Pavement material testing evaluates the properties of subgrade soils and construction materials used in pavement design. Testing may include CBR, plasticity and particle-size distribution to assess strength, behaviour and suitability for the proposed pavement structure.

    Why is reactive clay a concern for pavement design in Adelaide?

    Reactive clay can shrink and swell as moisture conditions change, causing movement beneath pavement structures. Pavement design in Adelaide should account for reactive subgrades to reduce the risk of cracking, deformation, moisture ingress, and premature pavement deterioration.

    When is a pavement investigation required?

    A pavement investigation is typically required before designing roads, carparks, or hardstands where subgrade conditions are unknown or variable. It can also investigate existing pavement failures and identify reactive clay, uncontrolled fill, or weak subgrades before rehabilitation or construction.

    Does BHM Geotechnical carry out both investigation and design?

    Yes. BHM Geotechnical provides pavement investigation and design services across Adelaide and South Australia. Combining both services allows investigation findings, including subgrade strength, reactivity, and material properties, to directly inform pavement thickness, material selection, and other design recommendations.

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