Chapter 2: General Observations

Throughout the study, the team gathered valuable information not only at formal presentations and discussions, but also during site reviews and travel between venues. Other good sources of information were the informal one-on-one discussions and question-and-answer sessions individual team members had with their hosts. The information derived through these and other methods of communication is included below. These general observations are categorized by subject matter and country.

The study validated the fact that pavement preservation strategies and techniques used throughout the United States enjoy levels of success similar to those used in the host countries. Among them are institutionalizing systematic methods of programming and dedicated funding, using high-quality materials and sophisticated construction equipment, including pavement preservation as an internal element of long-term performance, and recognizing and overcoming potential barriers to success.

ROAD SYSTEM

France

• The roadway system in France includes the following networks:
  
  
  • 10,711 kilometers of Motorway toll roads (7,186 kilometers under concession)
    
    
  • 2,500 kilometers of non-toll Motorway roads
    
    
  • 28,000 kilometers of national (state) roads
    
    
  • 316,000 kilometers of department (county) roads
    
    
  • 580,000 kilometers of commune (city) roads
    
    
• Each network is managed separately and has a distinct purpose and expected level of service. Generally, toll roads are maintained at a higher level than the rest of the system because of a dedicated, toll-supported revenue stream.
  
  
• Construction of the French Motorway system, which serves as the equivalent of the U.S. Interstate system, began in the 1960s. Pavement
  sections built sinces 1980 were designed with an expected life span of 30 years. Since the system is relatively young, its overall condition is quite good. Forty percent of traffic is on the national network and 90 percent of the system is asphalt concrete.
  
  
• Although research and development activities are centralized, contractors are involved both in quality assurance and in developing technologies to achieve better results through the use of proprietary products.

Figure 3. The team visited sites where pavement preservation treatments have been applied

South Africa

• The Republic of South Africa's road network includes national, provincial, and local systems. The national system includes about 19,000 kilometers of primary roadway, which is similar in function to the U.S. Interstate system. The South African National Road Agency Limited (SANRAL) manages about 7,000 kilometers. The remainder is managed provincially but has been identified as serving a national function. SANRAL is a registered company of which the National Minister of Transport is the sole shareholder. It was created in 1998 to replace the Chief Directorate, National Roads of the National Department of Transport. It is run like a business instead of a government department. Provincial road systems total about 170,000 kilometers, while local systems include about 350,000 kilometers. About 64,000 kilometers of the local system is surfaced. It is up to the provinces to fund, build, repair, and operate their individual systems.
  
  
• The national network consists of 45 percent seals, 46 percent hot-mix asphalt of various types, 8.7 percent jointed plain concrete pavement, and 0.3 percent continuously reinforced concrete pavement. South Africa has 100 kilometers of concrete overlays on flexible pavements and 30 kilometers of 160-to-230-millimeter concrete inlays on flexible pavements.
  

Australia

• The Australian road network is made up of national, state, and local systems. The national system includes roads that connect states and have been federally identified as serving national needs. Maintenance responsibility for the national road system lies with the states. Funding for maintaining this system comes from the national government. The remainder of the state-maintained system provides arterial service within each state. More than 75 percent of all traffic occurs on the state-maintained network. States are broken up into smaller regions that manage maintenance of the state system at the local level. Municipalities and other local entities manage local systems. Approximate network lengths are included in the following table:
  

• Truck rates are growing at rates similar to those in the United States. This has a significant impact on Australian roads because of permissible triple axle configurations.
  
  
• States use benchmarking to evaluate the progress and effectiveness of pavement maintenance strategies. The Victorian State Road Authority (VicRoads), for example, reduced routine maintenance costs from $920 per lane kilometer in 1993 to $730 per lane kilometer in 2000.
  

PRIVATIZATION

France

• Of the total Motorway network, 7,186 kilometers are owned and operated by concessionaires (builder/operator). A toll of half a franc per kilometer (6 cents per mile) is charged to users to cover costs of financing, construction, operation, and maintenance and to generate a profit. Concessionaires sell shares in the road system and are allowed to hire whomever they wish to do repairs.
  Concessionaires are totally liable for safety issues. The French government is a shareholder in the concessionaire companies and over half of the total system budget is generated from toll revenues. This partnership appears to be successful.
  
  
• French concessionaires are totally integrated in both design and construction. France's unique contractor/owner relationship encourages innovation and has led to a number of patented processes and mixes.
  

Australia

• The general trend is toward privatization of road functions, including design, maintenance, and construction. The extent varies from state to state. According to the states' data, this has led to cost reductions. Western Australia has contracted out more than 90 percent of its activities and has reduced its staff from more than 2,500 to 700 employees. State agencies have some concerns about their ability to adequately administer maintenance contracts, but are committed to the success of the program.
  
  
• Privatization is carried out through a number of contract strategies:
  
  
  • Single-invitation contracts - Negotiated contracts with local governments to do work. Because rural populations are sparse and local economies may not remain viable, contracts are negotiated with local governments to support the local economy. This may have some effect on the type of work performed on the local network.
    
    
  • Performance-specified maintenance contracts - Long-term (10-year) contracts based on roughness, cracking, rutting, and texture for pavement performance and other measures for additional routine maintenance items.
    
    
  • Scheduled-rate contracts - Contracts with set schedules for unit costs of work necessary for maintenance items and rehabilitation work
    
    
  • Tendered contracts - Low-bid contracts.

FUNDING

France

• With the exception of tolls, no dedicated public funding source generates funds for roads. All taxes, including fuel taxes, go to a general fund from which a road budget is allocated. Funding allocations for preventive maintenance are based primarily on roadway use, not on condition. Specific treatments are selected at the local level. Funding allocations for rehabilitation, or structural repair, are based on condition. In both cases, funds available for allocation are obtained from a general fund and the magnitude of funds available for maintenance is determined through the political process.
  
  
• The Ministry of Transport's 1998 budget was:
  
  
  • 1.3 billion euros - state budget
    
    
  • 643 million euros - local authority financing (regions, counties, towns)
    
    
  • 2.4 billion euros - Motorway concession company financing (loans, self-financing, equity capital)
    
    
  • 564 million euros - proportion of toll revenue allocated to maintenance
    
    
• Maintenance of tollways where funding is consistent and predictable is good, but a 2001 analysis of government activities indicated not enough money is available for preventive maintenance on the national system.
  

South Africa

• SANRAL's policy is to foster social equity and sustained economic growth, as well as to promote employment and redistribution of wealth. Consequently, social needs have a high priority and are weighted against the role transportation plays in the country's economy.
  
  
• No ongoing dedicated funding source is available for road building and repair, although a three-year conditional grant provides some funding. Money is appropriated to SANRAL for national roads from a central budget system, but there is no specific formula or amount. The government also allocates money for each provincial budget. The provincial government then determines how much to spend on building and repairing roads. In most cases, toll revenues can be spent only on toll roads.
  

Australia

• No dedicated funding sources are available for transportation in Australia. Taxes are collected on fuel, automobile sales, and licensing and are deposited into general government accounts. Funds are then allocated to the states from the federal government through the budget process.
  
  
• Maintenance responsibility for the national road system lies with individual states. Funding for managing the system comes from the federal government, but in most cases funds provided are insufficient to fully maintain these facilities. Some states subsidize the funding shortfall, while others modify their national roads maintenance by optimizing their programs with the funds provided. These allocations are not based on pavement management analysis. For the most part, states spend a high percentage of their maintenance funding on preservation rather than rehabilitation. Some agencies such as VicRoads make minor improvements in each of their preservation projects without committing to a rehabilitation treatment.

PAVEMENT MAINTENANCE STRATEGIES

France

• In the French road system, the philosophy is to build a strong base so that the wearing surface needs repaving only every 10 or 15 years and a structural overlay needs to be placed every 20 years. Reconstruction is not common. Several overlay types (thin, ultra thin, etc.) are used, with a specific course thickness assigned to each. For the national highway system, rehabilitation projects are selected at the national level. For all other roadways, decisions on types of treatments are made locally.
  
  
• Pavement preservation and maintenance activities focus on functional issues, such as improved skid resistance, noise reduction, and enhanced ride. This emphasis mirrors the Ministry of Transportation's stated goals for maintenance of improved safety, environmental protection, and greater efficiency of public service.
  

South Africa

• Pre-coating of aggregate is used to a large extent to prevent aggregate loss. Pre-coating is accomplished by blending bitumen and aggregate in the stockpile. The primary pavement maintenance treatment is a variety of surface seals, selected on the basis of both research and hands-on experience. Each maintenance project is engineered on the basis of established design guidelines, including a decision-tree approach.
  

Australia

• Asset management programs for pavement maintenance and rehabilitation are used by all state road agencies in Australia. These programs, similar to pavement management systems in the United States, vary from state to state. Asset management programs are well thought out and include prioritization modeling as well as cost-benefit analysis. Asset management programs have been used effectively in identifying needs and in convincing management that more funding is needed for road maintenance.
  
  
• Except in urban areas, the road-building philosophy in Australia is to build a deep subbase and a strong unbonded base course with a thin asphalt wearing course.
  
  
• In New South Wales, the Roads and Traffic Authority has developed a strategy that includes a five-year infrastructure maintenance plan. This plan identifies road maintenance needs based on road system performance, assessment of road features, condition, and community benefits.

Figure 4. A typical heavy-duty granular pavement section includes a deep subbase

	Surfacing - Size 14/7 Two-Coat Chip Seal
	Base - 200 mm Class 2 Crushed Rock
	Upper Subbase - 150 to 200 mm Class 3 Crushed Rock
	Lower Subbase - 150 mm Granular Material
	Select Filling - 150 to 450 mm (CBR 5 to 10)
	Subgrade - Average CBR 2 to 5

• In Western Australia, the most commonly used preservation treatment in urban areas is milling the surface layer and applying a stress-absorbing membrane
  interlayer followed by a thin (30-millimeter) overlay. On lower-volume roads, they reseal (chip seal) roadways and achieve good performance. Seals are
  expected to last 12 to 15 years and asphalt overlays 20 years. Crack sealing is often done to prevent water from getting into the base course, as keeping the
  subgrade dry is considered crucial.
• In VicRoads, the maintenance strategy consists of a six-year program with the goal of maintaining the pavement roughness of the network at an international
  roughness index (IRI) of less than 4.2 meters per kilometer (270 inches per mile). Since 1994, 10 percent of the network each year has been preserved using this strategy.

MATERIALS

France

• Quality aggregates, considered very important, are the foundation for the performance and longevity of both initial construction and pavement preservation or maintenance treatments, including the use of gap-graded fine mixes.
  
  
• Aggregate properties include 100 percent fully crushed, Los Angeles (LA) abrasion loss less than 15, micro-duval less than 20, and polished stone value less than 0.5. The gradations range from continuously graded to gap-graded. Gradation bands are also tight, which ensures a quality material.
  
  
• Half of surface dressings are done with hot bitumen and half are done with emulsions.
  
  
• The primary crude oil source for bitumen is Venezuela.
  
  
• A number of hot mixture types are used and include the following:

• For microsurfacing applications, a concentrated solvent sealer emulsion made from 50-70/70-100 penetration grade base stock is used. Often fibers are used with an additive system attached to a standard microsurfacing machine. These fibers improve adhesion.
  

South Africa

• Factors critical to the success of pavement preservation treatments include a willingness to invest in quality aggregates, even if they must be transported long distances, along with paying significant attention to size and gradation. Specifications require 100 percent crushed material with 0.5 percent or less passing the 200 sieve for a single aggregate used in hot and cold applications.
  
  
• Typical aggregate top sizes, lift thickness, names, and binders used for hot mixes are as follows:

• Refiners are available and crude is imported from a variety of sources.
  
  
• The principal use of emulsions is for fog sprays and rejuvenation for seals. Most surface dressing is done using modified hot binder.
  
  
• Some surface treatments use aggregates with a maximum size of 19 millimeters.
  
  
• Crumb rubber asphalts and other types of modified bitumens are used in a variety of pavement applications, ranging from surface dressing to hot-mix asphalt.
  

Australia

• Polymer-modified binders are used extensively in Australia for both chip seals and hot-mix asphalt. For chip seals, hot applied bitumen is used predominantly. Some cutbacks and emulsions are used as well. The hot applied bitumen is modified with a number of different types of additives - styrene butadiene styrene (SBS), styrene butadiene rubber (SBR), ethylene vinyl acetate (EVA), ethyl methacrylate (EMA), and crumb rubber - but SBS and crumb rubber are the two most widely used. The same is true for hot-mix asphalt mixes. Most are SBS-modified class 170 (80-100 penetration grade), class 320 (50-60 pen), and class 600 (40 pen) binders. The polymer loadings are normally in the six percent range, nearly twice the amount generally used in the United States. The amount of crumb rubber ranges from 16 to 20 percent.
  
  
• In general, the Australians have strict requirements for the quality and gradation of aggregates used in surface courses. For example, chip seal aggregate is friction resistant, clean (maximum of 0.5 percent passing the 200 sieve), a maximum size of 10 or 14 millimeters, and single sized. In most instances, chips are pre-coated with bitumen to promote adhesion and early return to traffic. Typical aggregate spread rates for single-layer seals are as follows:

• In rural areas, poor-quality materials called bush gravel with California bearing ratio (CBR) values of 10 or less are used for base material. A "grass-roots grade" is prepared. The poor material is treated with lime for stabilization, and then a cutback asphalt primer is applied and finished with a chip seal. The local gravels are often sensitive to moisture infiltration. This use of local materials for base courses is one reason for the Australian emphasis on maintaining a waterproof surface and the country's intensive chip seal program.
  
  
• If locally available base course materials are of a lower quality, they are stabilized with a number of different products, including lime, fly ash, bitumen, and cement. In some areas, crushed rock base is treated with two percent cement and left in stockpiles at the quarry to be hydrated.
  
  
• In New South Wales, crushed basic rocks such as basalt, intermediate rocks such as dacite, and less frequently acidic rocks such as granite are used in asphalt and sprayed seals. Crushed river rubble is also used on low-traffic roads. In addition, specialized aggregates are used in surface courses to increase friction and improve skid resistance.
  
  
• Geotextiles are used in most states in a number of different applications. They can be used as a stress-absorbing membrane interlayer, in a sandwich seal, in a double application, and directly under a chip seal. The primary reason for use is the delay of reflective cracks from the treated base courses.
  
  
• In Western Australia's rural areas, natural gravel base courses are sometimes primed with cutback bitumen, covered with river sand or crusher dust, and left open to traffic for six to eight months. A single chip seal is then applied to serve as final wearing surface.
  

PAVEMENT MANAGEMENT SYSTEM

France

• A large variety and amount of data are generated about pavement and roadway conditions on all roads through the use of specially developed equipment. The entire roadway system is evaluated on a three-year cycle. France's ultimate goal is to use its pavement management system for designing surface preservation treatments, as well for as providing information to management about system pavement conditions.

South Africa

• The data-intensive system uses state-of-the-art technology, computer programs, and global positioning system technology. The information is used for measuring system condition, predicting service life, and selecting future projects. The well-managed program is used to validate cost benefits of pavement preservation and maintenance activities.
  
  
• The pavement management system applies a two-step process of generating strategies and their optimization. The optimization process aids in selection of the most economical strategy within budget parameters. Even though the pavement management system determines optimum strategies, a field panel selects the final construction work program. This selection is then reviewed and final project selection may be modified to meet local needs and considerations.
  
  
• A key component of the pavement management system road condition analysis is the annual visual evaluation, which is based on a national standard (TMH9). Raters are trained and certified to insure consistency among the provinces. The annual evaluation is combined with mechanical measurements for use in the calculation of road condition indices. Mechanical measurements of the road, done every two to three years, include transverse and longitudinal profiling. The road indices are then used to formulate optimization of preventive maintenance based on available funds.
  

Australia

• All states use pavement data collection systems. Data gathered includes, but is not limited to roughness, rutting, strength (deflection), texture, cracking, skid resistance, and seal coat age.
  
  
• Queensland has developed in-house software to serve as a decision support tool for the road asset maintenance policy and strategy at the state and district levels. Other states use commercially available software for this purpose.
  

MISCELLANEOUS

France

• The French are concerned about the impact of traffic noise in urban areas and require open-graded mixes to reduce noise and increase friction.
  
  
• Most maintenance is under contract, with the exception of mowing, winter maintenance, signs, and trash pickup. Consequently, concession providers are typically roadway contractors partnered with toll operators.
  
  
• The Ministry of Transport completes an annual user survey, pulling highway users off the road to ask them a set of questions. The same questions are asked each year to determine trends and measure performance. Each year, 10,000 users on the Motorway system and another 20,000 users on the national system are surveyed. The maintenance division responds to the survey by modifying priorities and budget. On department and municipal roads, comment cards located at gas stations are available for users to complete with any comments they desire - positive or negative.

South Africa

• SANRAL and provinces rely on consultants for design, analysis, and on-site construction management.
  
  
• Build, operate, and transfer facilities constructed by concessionaires are gaining popularity. These are constructed and operated using performance-based contracts and the concessionaire has full maintenance responsibility for the life of the contract, up to 30 years. This approach not only provides capital for road construction in a tight budget environment, but it also generates revenue because concession profits are shared with the government above a certain rate of return. Also in use is a product certification and product performance guarantee system that requires guaranteed results for various distresses, such as skid, rut, and ride.
  
  
• The product certification and product performance guarantee system has three levels. Level I is a one-to-three-year guarantee on workmanship. Level II is a guarantee on product of three to 10 years. Level III is a guarantee on product performance by the contractor of 10 to 30 years.
  
  
• Surfaces are kept sealed to keep water from getting into the base. Visual observation or inspection by experienced personnel is critical to an effective pavement preservation or maintenance program.
  
  
• A serious problem for managing pavement assets in South Africa is overweight vehicles. It is estimated that 17 to 20 percent of all trucks are overloaded and that these trucks account for 60 percent of road damage. The legal single axle load is 9,000 kilograms = less than 9 kN, and the maximum truck weight is 56,000 kilograms = less than 56 kN. It is not uncommon to have greater than 900 kPa tire pressures.
  

Australia

• National guidelines for pavement condition data collection and treatment selection have been established in Australia through AUSTROADS.
  
  
• Overweight trucks are a problem in Australia. Large trucks called road trains are used in various states. The largest of these trucks are 53 meters long, weigh 250,000 pounds, and have 98 wheels and 25 axles. The loads on these trucks meet Australian axle load limits of 80 kN. Tires on these trucks cause significant shear stresses on pavement, however, because of their drive axle configuration and high tire pressures that can reach 900 kPa. Australia discourages the use of wide single tires known as super singles by reducing loading allowances, as these tires have been shown to cause seven times more damage than dual tire configurations.
  
  
• In Queensland, state weight enforcement includes not only fines on the driver, but also fines on the trucking company and possible impoundment of the vehicle. Telemetric devices are used to read weight-in-motion data and identify trucks for detailed weighing.
  
  
• On rural roads in New South Wales with good sight distance, edge stripes are used without centerlines on two-lane, eight-meter-wide roads. Trucks are encouraged to use the center of these roads to preserve roadway edges.
  
  
• Regions submit projects to state transportation offices, where a mix of projects is selected. The project mix is based in part on pavement management data and analysis and in part on local factors.
  
  
• For low-volume, unsealed roads, a technique of stabilizing the edges of the formed roadway is used occasionally to keep moisture out of the traveled way. This is used in lieu of edge drains.
  
  
• Road safety is an important aspect of overall maintenance activities. Special programs focus on localized roadway improvements, including surface or pavement treatments for high-accident locations. Special funding derived from vehicle insurance company profits supports some of these programs.