PAVEMENT ENGINEERING

Knowledge and understanding

This course provides students with the technical knowledge relevant to the field of Pavement Engineering, addressing asphalt materials, pavement design and maintenance. Starting from the constituent materials — bitumen, aggregates and asphalt materials — the course develops the understanding of Asphalt Concrete mix composition and design, and then of pavement design, describing the recent evolution of design procedures from empirical to analytical (mechanistic) methods, together with the assessment of pavement conditions and design for maintenance, including overlay design.

On successful completion of the course, students will know the procedures for pavement analysis, design and maintenance, including material selection and characterisation, mix design of asphalt concrete, design of pavement layers using both empirical and mechanistic methods, and performance evaluation of existing pavements through visual inspection, manual systems, high-speed equipment and instrumented vehicles. Students will also acquire the fundamental knowledge underpinning the laboratory testing of materials.

Applying knowledge and understanding 

Students will be able to apply the acquired knowledge and the fundamental laboratory testing skills to solve practical pavement engineering problems. In particular, on successful completion of the course students will be able to:

• classify the bearing capacity of the subgrade, its swell potential and frost susceptibility;
• select the most appropriate technique for soil stabilisation;
• identify and analyse traffic load parameters;
• identify and analyse weather factors for pavement design;
• select and test materials for pavement layers;
• perform the mix design of asphalt concrete;
• design the layer thicknesses of the pavement structure;
• identify maintenance needs over the service life of the pavement;
• identify the distress and performance of in-service asphalt pavements;
• design overlays to improve the residual life of the pavement

Making judgements 

Students will develop the ability to critically evaluate the alternatives available in pavement engineering — from material selection and mix design to structural design and maintenance strategies — comparing solutions in terms of technical performance, durability, cost and sustainability. They will be able to interpret the results of laboratory tests and pavement condition surveys, and to formulate independent judgements on the most appropriate design and maintenance options for a given traffic, subgrade and climatic context, including under conditions of incomplete data.

Communication skills 

Students will be able to present and justify, using appropriate technical language, the methodological choices adopted and the results of their analyses and tests, both in written form through the preparation of technical reports and design deliverables and orally in the presentation and discussion of their work. They will also be able to communicate effectively with the technical and non-technical stakeholders involved in the design, construction and management of road pavements.

Learning skills

Students will have acquired a method of study and work that will enable them to independently update their competences in line with the evolution of materials, testing methods, design procedures and technologies in the field of Pavement Engineering, so as to approach subsequent educational pathways and professional practice with autonomy.

The course is delivered through lectures, tutorials, laboratory activities and the development of a design project (technical report). 

Lectures, supported by teaching materials and presentations, introduce the theoretical foundations concerning materials, structural design and pavement maintenance. 

Tutorials, of a numerical and applied nature, guide students in solving practical problems such as material characterisation, mix design of asphalt concrete and thickness design of pavement layers using empirical and mechanistic-empirical methods. 

Laboratory activities, also delivered in demonstrative form, illustrate the main tests on materials (aggregates, binders and mixes) and the systems used to survey pavement conditions. The design project, carried out individually, requires the integrated application of the acquired knowledge to a case study and concludes with the preparation of a technical report and its presentation and discussion.

Traffic, environmental conditions, soil and drainage

Weather and Environment factors. Traffic and load distribution concepts. Load Equivalency Factors. Subgrade, Subbase, Drainage. Soil stabilization concept and methods.

Material characterization and asphalt mix design

Historical background. Pavement performances. Pavement Type: Flexible pavement, Rigid pavement, Special Pavement: Draining-Sound Absorbent, Composite. Asphalt Concrete. Properties and characteristics of binders and aggregates. Laboratory material characterization. Viscoelastic nature of asphalt and direct measure of stiffness. Types, properties and design of asphalt mixes. Marshall and Superpave mix Design. Harmonized European Specifications.

Structural design

Resilient modulus, Dynamic modulus of asphalt concrete. Fatigue cracking, Rutting and permanent deformation. Pavement performance and analysis period. Pavements catalogs. Empirical Methods. Mechanicistic-Empirical Methods.

Maintenance and rehabilitation

Maintenance and rehabilitation of asphalt pavement. Pavement Management Systems (PMS). Pavement Survey. Nondestructive tests. Bearing capacity, Unevenness, Skid resistance and surface texture, visual evaluation of Distress. Overlay design.

Textbooks

Guide for Design of Pavement Structures, 4th Edition, AASHTO, 1993 (pdf)

Mechanistic-Empirical Pavement Design Guide, AASHTO, 2008 (pdf)

Catalogo delle Pavimentazioni Stradali, CNR, 1994 (pdf)

Highway Engineering - Pavements, Materials and Control of Quality. A. Nikolaides. CRC 2015

Pavement Engineering, Rajib B. Mallick, Tahar El-Korchi, CRC, 3nd edition, 2016

F.A. Santagata et al. Strade. Vol. 2 Teoria e Tecnica delle Costruzioni Stradali - Pearson, 2016

Huang Y. H. (2003). Pavement Analysis and Design. Prentice Hall.

Mallick R. B., El-Korchi T. (2008). Pavement Engineering. Chapman and Hall/CRC.

The assessment of learning is based on an optional mid-term oral test, a final oral examination and the evaluation of the assigned homework and of the final pavement design project. No written tests are envisaged: assessment is carried out through an oral interview with open-ended questions, aimed at evaluating knowledge of the contents, the ability to apply it and command of technical language.

Registration. Registration for the final examination is made through the University portal, in the sessions published in the examination calendar; registration for the mid-term test is made by e-mail to the lecturer, within the deadlines indicated during the lectures.

Mid-term test (optional) — weight 30%. It is held during the teaching period and covers the topics listed in the examination questions: section A) 1÷10, 12, 16, 17 – section B) 1÷3. It consists of an interview lasting approximately 20–30 minutes, with a number of open-ended questions. Passing the mid-term test exempts the student from the corresponding topics in the final examination.

Final examination — weight 45%. For students who have passed the mid-term test, it covers the topics listed in the examination questions: section A) 11, 13÷15, 18, 19 – section B) 4÷10 – section C) 1÷4. For students who do not take the mid-term test, the final examination covers all the topics in the list of questions and also absorbs the weight of the mid-term test (overall weight 75%). It consists of an interview lasting approximately 30–45 minutes, with open-ended questions and discussion of the deliverables.

Homework and design project — weight 25%. The evaluation takes into account the timely execution and quality of the assigned homework and the quality of the final pavement design project. Submission of the homework and of the design project is mandatory and is a prerequisite for admission to the final examination; deliverables must be submitted within the deadlines agreed with the lecturer and are discussed during the oral examination.

Grading scale. Marks are expressed out of thirty. The examination is passed with a minimum mark of 18/30; the maximum mark is 30/30, with the possible award of honours (cum laude). The final mark is determined by the weighted average of the tests according to the weights indicated above (mid-term test 30% + final examination 45% + homework and project 25%, or final examination 75% + homework and project 25% in the absence of the mid-term test). Attendance and active participation in the teaching activities are positively taken into account.

Attendance and active participation will be positively evaluated.

Topics and Exam questions [reference number of the teaching material]

A) Materials

1.Subgrade classification [3.0]

2.Bearing Capacity Investigation Plate test (static plate, FWD, LWD) [3.0]

3.Bearing Capacity Investigation Resilient Modulus [3.0]

4.Bearing Capacity Investigation Empirical tests (CBR) [3.0]

5.Compaction (proctor test, site control) [3.0]

6.Seasonal variation, equivalent design value of Mr [3.0]

7.Aggregate characteristics and laboratory test [5.1; 5.2, 5.3]

8.Asphalt Concrete components and Mix Volumetric properties [5.4]

9.Asphalt binder typologies and applications (natural, artificial, cutback, emulsion, foamed, modified, special) [6.1]

10.Asphalt binder empirical testing and classification [6.2]

11.Asphalt binder rheology: viscosity definition and laboratory test (dynamic, kinematic viscosity) [6.2]

12.Asphalt binder stiffness (IP, Van der Poel) [6.2]

13.Asphalt binder rheology: viscosity and complex modulus (RV, DSR) [6.3]

14.Asphalt binder rheology: Ageing, stiffness and Strength (RTFO, PAV, BBR, DTT) [6.3]

15.Asphalt Binder Performance Grade [6.4]

16.Asphalt Concrete Mix Design: Marshall [7.0]

17.Asphalt Concrete Mix Design: Superpave [5.3; 8.0]

18.Asphalt Concrete Characteristics: Complex Modulus model and definition [9.0]

19.Asphalt Concrete Characteristics: Modulus Laboratory testing and empirical formulas [9.0]

B) Design

1.Empirical Mechanistic Design: Traffic factors (Traffic load types and distribution) [2.0]

2.Empirical Mechanistic Design: Environmental factors (temperature, moisture) [2.0]

3.AASHTO empirical Design: Equivalent Standard Axle Load, ESALs in the design period [2.0]

4.AASHTO empirical Design: Structural Number (PSI, Mr, R, S, ESAL) [12.0]

5.AASHTO empirical Design: Swelling [12.0]

6.AASHTO empirical Design: Layer coefficients and thickness distribution [12.0]

7.AASHTO Overlay design [16.0]

8.Empirical Mechanistic Design: Multilayer Elastic System [10.0]

9.Empirical Mechanistic Design: Fatigue cracking model, laboratory test and design formulas [10.0]

10.Empirical Mechanistic Design: Rutting model, laboratory test and design formulas [10.0]

C) Maintenance

1.Effective Pavement bearing capacity: Falling Weight Deflectometer (test, layer moduli, SNeff) [11.0]

2.Skid resistance: GRIP, SCRIM (equipment and coefficient estimation) [13.0]

3.Pavement longitudinal profile: micro-macro-mega texture, MPD, IRI (equipment and coefficient estimation) [13.0]

4.Pavement surface distress: classification and measurement systems (cracks, rutting) [10.0; 13.0]