Geotechnical Aspects of Pavements

By the end of this course, you will be able to:

• Identify geotechnical risks that affect pavement and embankment performance during design and construction
• Interpret geotechnical data to support informed pavement and foundation design decisions
• Evaluate and select appropriate ground improvement and remediation strategies for subgrade and foundation conditions
• Develop practical design alternatives to address subgrade and embankment challenges under real‑world constraints
• Apply empirical and mechanistic‑empirical procedures to the design of asphalt pavement systems

Description

Pavement performance is highly dependent on how well subsurface conditions are understood, characterized, and incorporated into design and construction decisions. In practice, inadequate geotechnical input or misinterpretation of subgrade behaviour can lead to premature distress, constructability issues, and increased lifecycle costs. Engineers are often required to make design and remediation decisions while balancing uncertainty in soil conditions, traffic demands, climate effects, and construction limitations.

This course provides a practical framework for integrating geotechnical engineering principles into asphalt pavement design, evaluation, and construction. You will examine how soil properties, groundwater conditions, settlement, strength, and stiffness influence pavement behaviour and how these factors are addressed through investigation, testing, ground improvement, and material selection.

Through applied discussions, design procedures, and case examples, the course connects geotechnical fundamentals with empirical and mechanistic‑empirical pavement design approaches. Emphasis is placed on methods that can be applied directly to new construction, rehabilitation, and reconstruction projects, supporting more reliable, defensible, and performance‑based pavement design decisions.

Who Should Attend

This course is designed for:

• Civil engineers and engineering technologists involved in pavement or roadway projects
• Geotechnical, pavement, and materials engineers supporting design or construction
• Engineers working in transportation, municipal, and infrastructure organizations
• Consultants responsible for investigation, design, specifications, or quality assurance
• Professionals involved in pavement rehabilitation, reconstruction, or asset management

Part 1 - Geotechnical Engineering for Pavement Engineers

Background
Soil types, mass-volume relationships, grain size distribution, index properties, USCS/AASHTO classification, total vs. effective stress, load distribution

Water and Soils
Capillarity, shrinkage/swelling, freeze-thaw, frost heave, permeability/hydraulic conductivity, seepage flow (one- and two-dimensional), constant and falling head tests

Consolidation and Settlement
Components of settlement, time-rate, laboratory consolidation (oedometer) tests, compressibility characteristics, pre-consolidation pressure, over-consolidation ratio, secondary consolidation (creep)

Strength and Stiffness of Soils
Cohesive/frictional components of shear strength, undrained vs. drained strength, field and laboratory testing, repeated loading effects, modulus and resilient modulus

Ground Improvement
Deep vs. shallow methods, stabilization, geosynthetics, compaction, equipment, and procedures

Applications and Case Studies
Embankments, excavations, dewatering/drainage, ground improvement for stability and settlement mitigation

Part 2 - Pavement Engineering

Pavement Investigation
Geotechnical investigation, visual inspection, drainage, laboratory testing, non-destructive testing

Subgrade and Granular Layers in Pavement Structure
Requirements for subgrade, testing including CBR and Falling Weight Deflectometer (FWD), compaction requirements, standard and modified Proctor tests; granular layers - objectives, material types, granular base and subbase

Hot-Mix Asphalt
Asphalt cement (AC) - performance grading testing, advanced testing (MSCR, DENT, Ash, Extended BBR); compatibility of AC and aggregates, stripping; other HMA materials, characteristics; HMA mix design methodologies - Marshall and Superpave - basics, volumetrics, procedures

Pavement Design and Performance
Empirical and mechanistic-empirical including AASHTO MEPDG; the concept of Equivalent Single Axle Loads (ESAL); inputs - subgrade soil, traffic, climate, materials, other; design analysis and performance models and analysis; specifications; the importance of drainage

Construction
Introduction: subgrade preparation, granular layers, HMA production, delivery and placement, joint construction; Quality Control/Quality Assurance testing and acceptance

Questions and Answers, Feedback on Achievement of Learning Outcomes

Concluding Remarks and Final Adjournment