XVIIIth World Road Congress - Brussels 1987 - National reports


Question 1: Earthworks, drainage, subgrade

Question 2: Flexible Roads

Question 3: Construction and maintenance of rigid pavements

Question 4: Interurban roads

Question 5: Roads in urban areas

Question 6: Roads in developing regions

Question I: Earthworks, drainage, subgrade.

  • A. Earthworks
    1. Site investigation
    1.1 Developments in methods and organisation (namely optimisation of the programme scope).
    1.2 Innovations in techniques and equipment.
    1.3 Innovations in interpretation and processing of the results.
    2. Embankments
    2.1 Foundations of embankments on soft or compressible soils (lime columns, vertical drains, etc.).
    2.2 Use of non-traditional materials (unstable materials, industrial waste products, light materials...).
    2.3 Improvement and stabilisation of soil layers (products used, proportions, etc.).
    2.4 Use of geotextiles (tests, classifications, recommendations of use).
    2.5 Strengthening of soils (in sheets, reinforcements, fibres...).
    2.6 Widening and repair of embankments.
    2.7 Variations of moisture content of embankments materials (effects and remedial measures).
    2.8 Taking account of seismic effects.
    3. Cuttings
    3.1 Stability of cutting and natural slopes (drainage, geotextiles, rock falls, erosion, repairs, etc.).
    3.2 Taking account of the environment in selecting a method for excavation of cuttings (vibrations, blasting, lowering of water tables, etc.).
    3.3 Taking account of seismic effects.
    4. Carrying out earthworks
    4.1 New construction and control techniques (automation, remote control, energy saving aspects).
    4.2 Cutting in difficult ground (rocky, compressible, uns table soils...).
    4.3 Compaction
    - Execution (new plant, dry compaction, thick layers, influence of the bearing capacity of the underlying layers, etc.).
    - Control and acceptance.
    4.4 Influence of weather conditions in carrying out earthworks (trafficability, frost, carrying out earthworks in very cold weather...).
  • B. Drainage
    1. Use of new materials (geotextiles...).
    2. Design and construction of drainage systems
    2.1 Design of drainage taking into account its influence on the performance of new and existing pavements.
    2.2 Draining courses under the pavement.
    2.3 Effects on the environment (storm lagoons, pollution, changes of water level...).
    3. Maintenance of drainage systems.
    3.1 Inspection and control.
    3.2 Repairs.
    4. Case histories of the influence of drainage on the performance of works
  • C. Subgrades
    1. Methods and non-traditional mate rials (geotextiles, indus trial waste products...).
    2. Stabilisation of subgrades (soil in situ) (sélection of agent, proportions, equipment...).
    3. Design of subgrades for construction traffic and as pavement support
    3.1 Economic optimisation of the subgrade taking into account :
    - its influence on pavement design,
    - climatic conditions,
    - sitework traffic.
    3.2 Protection of the subgrade against the action of sitework traffic and weather conditions.
    3.3 Assesment of the bearing capacity of the subgrade.

Pages 0-104 (19916 Ko)

Pages 105-210 (18344 Ko)

Pages 211-296 (17031 Ko)

Pages 297-417 (25082 Ko)

Question II: Flexible Roads.


Evolution in the general concept and use of traditional methods in the fiels of flexible pavements :
- effects of economic, social, energy conditions,
- influence of the change in the characteristics of the vehicle fleet (total weight, axle load, speed),
- design and behaviour in the long term,
- stratégies combining first investment/maintenance/strengthening.

  • 1. Practical design
    1.1 Checking practical design methods (catalogues, nomographs...).
    1.2 Adjusting practical design methods when entrance objectives or parameters do not correspond to traditional assumtions : very heavy traffic, very long service life, minimum or zero maintenance, urban traffic, low number of heavy axle vehicles, etc.).
    1.3 Adjusting design methods to layers in non-traditional materials : draining courses, recycled courses, courses with modified binders, use of by-products, waste products or recycled aggregates.
    1.4 Taking account of real loads (overloads).
    I.5 Taking account of the residual value of pavements in the design of overlays.
  • 2. Pavement performance, pavement management systems
    2.1 State of the art for testing and monitoring procedures.
    2.2 Use of data banks for pavement management systems.
    2.3 Rules of intervention for pavement maintenance and overlay.
    2.4 Choice of strategy.
    2.5 Choice of priority (optimisation).
    2.6 Efficiency criteria.
    2.7 Maintenance cost.
  • 3. Bituminous binders
    3.1 Traditional binders : change in the specifications and their influence on the quality of bituminous materials.
    3.2 Operational use of modified binders, of additives, of sulphur, of natural asphalts.
  • 4. Traditional and non-traditional bituminous materials
    4.1 Traditional dense graded materials : choice of formulas, performance at extrême temperatures (low and high), résistance to plastic deformation, resistance to ageing and cracking (thermal, fatigue cracking, etc.).
    4.2 Use of open-textured coated macadam, draining courses.
    4.3 Use of thin and very thin layers : surface dressings and slurry seals ; cold-mix techniques : binders, mixing, spreading, compaction.
    4.4 Surface dressings for motorways and heavily trafficked roads (heavy traffic and fast traffic).
  • 5. Untreated stabilized layers
    5.1 Concept and design of pavements with untreated stabilised layers : their use in stage development.
    5.2 Evolution of spécifications for untreated mate rials for pavement stabilised layers.
    5.3 Dry compaction or with low water content.
    5.4 Use of untreated reconstituted and wet-mixed materials.
    5.5 Durability, performance under heavy traffic, contribution to pavement résistance to plastic deformation.
    5.6 Influence of water (during the construction period as well as for the pavement in service).
  • 6. Non-conventional materials
    6.1 Marginal aggregates, by-products, waste products, recycling products, démolition products : field of use, sélection of parameters and thickness.
    6.2 Limit of application of traditional spécifications, development of requirements and adaptation of the spécifications to the fields of use.
    6.3 Advantages and disadvantages for the environment of an increased use of non-conventional aggregates.
    6.4 Assessment on service life, consumption of energy, construction and maintenance costs compared with traditional aggregates ; characteristic examples of use.
    6.5 Possibilities of substitution for traditional aggregates : data banks on natural and artificial resources.
  • 7. Thermoregenerations, recycling of bituminous coated mate rials on the site and in mixing plant.
    7.1 Field of use.
    7.2 Sélection of method.
    7.3 Sélection of composition (aggregates, binders, regenerating agents) and thickness.
    7.4 Comparison of spécifications with spécifications of traditional materials.
    7.5 Assessment of the use of recycled coated mate rials on long term performance, on energy content and on construction and maintenance costs.
  • 8.. Equipment
    8.1 Equipment for filling ruts.
    8.2 Development of drum-mixers : their use for high performance mixes and for recycling.
    8.3 Development of equipment for thermoregeneration and recycling on the site.
    8.4 Limits to use of very intense compaction.
    8.5 Consequences of the concentration of fixed mixing plants (increase in transport distances and temperature losses).
    8.6 Consequences of high temperature mixing on the quality of coated material and pavement service life.
    8.7 Equipment for treating demolition products.
  • 9. Techniques for severe climate areas
    9.1 Laying at low temperatures.
    9.2 Weight limits imposed during thaw conditions : sélection of load limits and effectiveness.
    9.3 Insulating layers.
    9.4 Effects of de-icing salts on pavement performance (binders, aggregates, wearing courses and road bases, etc.).
    9.5 Effects of studded tyres : special formulas for coated materials to resist studded tyres, effects on coated materials with modified binders.
    9.6 Filling ruts.
  • 10. Semi-rigid pavements and mixed structure pavements.
    10.1 Current concept practices (taking into account particular aspects of each type of binder used and formula selected to complu with the requirements specifications of upper bituminous layers) and design practices for the use of layers stabilised with wet mixes in new and strengthened pavements. Importance given to cracking. Minimum
    thickness of layers stabilised with hydraulic binders and of layers in bituminous coated materials.
    10.2 Long-term performance.
    10.3 Economic and energy considerations.
    10.4 Means for the prevention of cracks in bituminous layers and maintenance of cracked surfacings.

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Pages 372-484 (20839 Ko)

Question III: Construction and maintenance of rigid pavements.

  • 1. Design and behaviour in service
    1.1 Present design of new pavements, emphasising the new developments of the problems raised by the introduction of concrète technology.
    Interaction between maintenance policy and pavement design. Management systems. Models for forecasting pavement service life. Cost trends.
    1.2 Non-conventional and experimental pavements.
    1.3 Assessment of the technical and economic performance of old pavements.
    1.4 Pavements of low traffic and housing estate roads.
    1.5 Urban pavements (including pavements with a concrète roadbase and bituminous wearing course).
    1.6 Concrète block pavements.
    1.7 Concrète slabs on low-bearing or high volume change soils.
    1.8 Effects of very heavy vehicles. Considération in road pavement design.
    1.9 Pavements in sévère climate.
    1.10 Other applications of concrete : at airfield runways, harbour and industrial areas, on engineering structures, safety barriers, etc.
  • 2. Materials
    2.1 Cements for roads, blended cements. Changes brought by these cements to the concrete.
    2.2 Marginal and non-conventional aggregates. Properties, specifications and behaviour.
    2.3 Properties, specifications and behaviour of fresh and hard concrete.
    2.4 Use of admixtures for pavement concrete.
  • 3. Construction and control
    3.1 New equipment and construction methods.
    3.2 Provisions for slab/support interface.
    3.3 Dowels. Placing methods and tolerances.
    3.4 Methods of achieving evenness and surface texture, performance.
    3.5 Control methods, equipment and control tests during construction.
  • 4. Maintenance and rehabilitation
    4.1 Maintenance strategies. Pavement condition assessment and nondestructive monitoring. Intervention threshold. Maintenance costs.
    4.2 Maintenance methods and techniques. Local repairs. Resurfacing and retexturing : long-term assessment.
    4.3 Overlays on old concrète pavements.
    4.4 Concrete overlays on flexible pavements.
    4.5 Drainage of existing pavements.
    4.6 Recycling of pavement concrete.
  • 5. Subbases and road bases treated with hydraulic binders (concrete pavements and semi-rigid pavements)
    5.1 The cracking process and its control.
    5.2 New developments in the composition and construction of lean concrète and aggregates treated with hydraulic or pozzolanic binders (cément, slag, fly ash, etc.).
    5.3 New developments in the concepts and exécution of stabilised or improved materials (manufactured in mixing plant).

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Question IV: Interurban roads.

  • 1. Design and drafting of projects
    1.1 Planning objectives.
    1.2 Methods taking into account the economic and social factors and decision criteria.
    1.3 (Mathematical) models of traffic forecasting.
    1.4 Influence of the energy policy on project planning and design.
    1.5 Computers for data processing and design.
    1.6 Road data banks (general problems).
  • 2. Environment problems
    2.1 Methodology : environmental studies and impact studies in the various stages of project design.
    2.2 Factors considered in thèse studies.
    2.3 Environmental studies and impact studies ; implementation cases.
    2.4 Public participation and consultation.
  • 3. Safety
    3.1 Interaction of the various factors of the vehicle, infrastructure, driver, environment system.
    3.2 Actions taken to improve safety ; assessment of the efficiency of thèse actions :
    - technical characteristics or roads and vehicles,
    - equipment and operation,
    - control.
  • 4. Geometric standards
    4.1 Basic parameters independent from user behaviour (roads and vehicles).
    4.2 Basic parameters subject to driver fitness and behaviour.
    4.3 Adaptation of the géométrie characteristics in relation with the basic parameters, including the energy factor.
    4.4 Geometric characteristics of junctions and interchanges.
    4.5 Geometric characteristics for the improvement of existing roads.
  • 5. Level of service
    5.1 Factors influencing the level of service.
    5.2 Parameters considered (namely traffic costs, including use, vehicle maintenance and fuel consumption costs).
    5.3 Assessment of the level of service in terms of significant terms.
    5.4 Selection of the level of service for the various categories of roads, for motorways and interchanges.
    5.5 Relation between the level of service and the corresponding costs of the infrastructures and their equipment.
  • 6. Equipment and operation
    6.1 Information techniques for the users and communication with them :
    - external signalling by traffic signs with variable indications,
    - information given inside vehicles.
    6.2 Information techniques for the staff responsible for traffic.
    6.3 Traffic control techniques (for road networks, running sections, at road intersection).
    6.4 Service and rest areas.
    6.5 Spécial opération techniques (winter maintenance, blinding control...).

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Question V: Roads in urban areas.

  • 1. Transport policy and planning of urban roads
    1.1 Général urban transport policies
    - Provision of new urban roads.
    - Methods to increase vehicle occupancy rates, including restraints of car use.
    - Pricing policies to influence modal split.
    - Urban planning to minimise the need for transport.
    - Introduction of restrictions for traffic through areas.
    - Policies for solving problems by improved enforcement.
    - Other policies.
    - Future possibilities and studies.
    1.2 Economic and other aspects
    - Expérience in the economic benefit from new road building and improvements.
    - Balance between long and short-term road building and improvement projects on existing roads.
    - The effect of limited finance and budgetary restrictions on road building programmes and road designs.
    - Public participation.
    - Methods to reduce total energy costs.
    1.3 Planning aspects
    - Balance between the provision of improved urban and rural road networks.
    - Evaluation techniques for urban road proposals.
    - Facilities for public transport, interchanges, etc.
    - Park and ride, kiss and ride schemes.
    - Parking provision, cars, motorcycles and cycles, number and type of places.
    - Pedestrian zones and cycle track networks.
    - Access to and from high traffic generating points (i.e. exhibitions, stadia).
    1.4 Freight management
    - Freight policies including provision and location of depots and distribution terminals.
    - Benefits from the provision of other lorry facilities.
  • 2. Environmental aspects, safety, traffic forecasting and statistics
    2.1 Environmental aspects
    - Traffic noise, including effects of différent surfacings, noise level calculations, standards, noise in cuttings, noise protection measures and improvements in existing areas by new road construction.
    - Improving the environ ment of historic towns including use of unconventional vehicles.
    - Air pollution and its reduction.
    - Vibration and road designs to reduce the problem.
    - Environmental protection including justification for environmental measures.
    - Environmental impact studies.
    - Environmental impact of works during construction including statutory undertakers works.
    - Clearance of visual clutter.
    2.2 Safety
    - Measures adopted for safety reasons.
    - Effects of raodside furniture.
    - Accident studies.
    - Accident reporting including consistency of statistics.
    - The effect of different traffic speeds on residential roads including low speed limits (e.g. 30 km/hr) and layouts to achieve design speeds.
    2.3 Traffic forecasting
    - Survey techniques, modelling techniques and analysis of results.
    2.4 Statistics
    - Road data banks, underground services, road characteristics, etc.
    - Statistics and flows for car, pedestrian, public transport and cyclists movements.
    - Speed/flow relationships.
    - Accident, vehicle and travel time costs and analysis.
  • 3. Design and construction of urban roads
    3.1 The network
    - Provision for cyclists, pedestrians, lorries and other specific classes of traffic including the re-allocation of road space.
    - Choice of pedestrian areas, location and standards.
    - Segregation of pedestrians, cyclists, etc.
    - Provision of urban motorways.
    - Use of railway routes.
    3.2 Design of junctions
    - Geometric design.
    - Roundabout capacity and design.
    - Redesign of existing junctions.
    - Urban and suburban junctions design.
    - Junctions in tunnels.
    3.3 Surfacings
    - Developments in surfaces specifically designed for the urban road including footpaths, cycle tracks, parking areas, bus stops, etc.
    - Use of surface mate rials such as concrète blocks where disturbances from water, gas, electricity services, etc. are likely.
  • 4. Management and operation of urban roads
    4.1 Traffic management
    - Intersection capacity, including optimisation and priority junctions.
    - Major route management, including corridors, and introduction of physical limitations (&dquo;Woonerf&dquo;) techniques.
    - Priority for public transport.
    - Parking control and enforcement inculding residential and verge parking.
    4.2 Application of electronics to roads
    - Urban traffic control.
    - Traffic signal developments.
    - Use of microprocessors.
    - Communications with drivers.
    - Urban motorway entry and exit slip road control.
    4.3 Pedestrians and cyclists.
    - Pedestrian areas, problems of retail goods distribution.
    - Provision for low numbers of pedestrians and cyclists.
    4.4 Maintenance of the urban network
    - Management of maintenance in the urban environment, including statutory undertakers openings, access problems during works.

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Pages 115-214

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Pages 279-375 (20603 Ko)

Question VI: Roads in developing regions.

  • 1. Justification of road investments
    1.1 Accessibility : significant parameters, relationship between accessibility and development, including the case of remote and/or sparsely inhabited areas.
    1.2 Effect of pavement strength and roughness on transport costs.
    1.3 Social and economic impacts of road construction. Harmonisation of traffic and transport matters to facilitate road transport between countries.
    1.4 Geometric standards, including single lane roads.
    1.5 Regional network planning.
  • 2. Management of road investments
    2.1 Methods of monitoring and laws of pavement performance.
    2.2 Road management models.
    2.3 Maintenance stratégies : costs and performance.
    2.4 The control of construction costs.
  • 3. Operation of road network
    3.1 Accidents, users safety and behaviour, vehicle condition, legislation.
    3.2 Control of overloading and of vehicle condition.
    3.3 Road data banks : collection of appropriate data and adequate computer processing systems.
    3.4 Protection of the environment : pollution, noise, etc.
    3.5 Environmental influences on pavement performance.
  • 4. Design and construction technology
    4.1 Selection of pavement surfacing types for paved and unpaved roads.
    4.2 Evaluation of non-traditional materials and techniques : investigations and quality control.
    4.3 Design and strengthening of pavement : standards and nature of materials, methods and techniques adapted to local conditions.
    4.4 Laterites : state of the art.
    4.5 Modern methods for site investigations and availability of materials.

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