THE EXPERIENCE OF SOUTH AFRICA, WEST GERMANY, SPAIN, JAPAN, USA IN THE CONSTRUCTION OF CEMENT CONCRETE PAVEMENTS

ABSTRACT

Sharing and disseminating knowledge is essential if we are to continue to advance the practice of concrete pavement construction and maintenance worldwide. Toward this end, this report presents the proceedings of the Harold J. Hulme International Symposium on Concrete Pavement Design.

АННОТАЦИЯ

Обмен и распространение знаний имеет важное значение, если мы хотим продолжать совершенствовать практику строительства и обслуживания бетонных покрытий во всем мире. С этой целью в данной статье представлены материалы Международного симпозиума Гарольда Дж. Халма по проектированию бетонных покрытий.

Ключевые слова: Бетонные покрытия, автомобильная дорога, консервативность.

Keywords: Concrete pavements, highway, conservative.

Experience working with concrete roads in South Africa

Until 1968, concrete pavements were used only in special cases in the Republic of South Africa (RSA). They are built using manual methods and rudimentary factories that do not create the longitudinal profile required for modern transportation. As a result, the use of concrete roads was discontinued in the 1950s and 1960s. However, AASHTO road test results and studies and observations of modern concrete pavement performance, particularly in the United States, have sparked interest in modern concrete pavements as a means of meeting the rapidly increasing traffic load on highways in South Africa. Construction of modern concrete pavements started in RSA in 1968 and accelerated from the mid-1970s. The technology currently in use is based on that used in regions of the United States with similar climate conditions. As it was recognized that existing concrete pavement designs were probably conservative for South African conditions, an extensive research and testing program was initiated.

It was necessary to solve the following problems.

• Design flaws.
• Road base problems.
• Demand for materials.
• Preparation of concrete mixes.
• Transportation of concrete mixes.
• Construction problems.

Construction of concrete pavements in West Germany

In West Germany, concrete pavements are usually laid on top of a hydraulically or bitumen-bonded foundation in a convenient laying method. The thickness of these pavements has recently been increased from 5 to 10 inches, and these pavements are divided into 5 m long and 4.25 m wide slabs by joints to relieve stresses caused by limiting volume changes. The plates are not reinforced, ordinary Portland cement is used. Transverse seams are doweled, and longitudinal seams are anchored. Both dowels and anchors are vibrated into compacted concrete. The aggregates used on the concrete surface must have high frost resistance and at least half of the coarse aggregate must be crushed. Concrete must also be entrained to withstand the effects of heat and cold preservation agents. When damaged slabs are reconstructed, high-strength concrete containing superplasticizer is used. In summer, reconstructed segments can be reopened for traffic within 12-14 hours. When old concrete pavements are renewed, either the old concrete is broken up and a new pavement is placed on top of it, or the old concrete is crushed by a cutter and used as a cement-bound base aggregate.

In Spain concrete cover construction

In Spain, traffic and climate pose serious limitations, so design and construction specifications developed in other countries usually have to be adapted to Spanish conditions. Although the first concrete pavements in the country date back to 1915, mechanized construction was not introduced until the 1960s. In 1971, along with the California approach, slip-shaped coatings were introduced. This technique has undergone significant changes since the 1970s. -Recent work shows that to avoid joint failures (due to the heavy traffic that is common in Spain), the joints should be equipped with dowels, and this practice has been made mandatory in the latest standards.

Figure 1. Cross-sectional view of cement concrete pavement construction

Characteristics of longitudinal surface textures used in Spain are described, as Spanish roads represent the only large-scale use of such textures in Europe. Finally, some observations are made on the use of rolled compacted concrete pavements, which are mainly used on secondary roads but have recently been used on some major roads. This paper describes the current state of pavement technology in Japan. Traffic and weather conditions affecting pavement design and methods of selecting the pavement to be used are reviewed. Emphasis is placed on the type and structure of cement concrete (PCC) used, as well as its performance and construction methods. Future trends in the development of PCC coating technology in Japan are also described.

• Traffic conditions, weather conditions and special problems.
• The role of concrete pavement.
• Construction and use of concrete guides.
• Concrete pavement performance.
• Construction methods for concrete roads in Japan
• Construction methods used on national highways and major local roads.
• More efficient maintenance and repair methods.

Concrete pavements. USA

The article describes the current state of concrete pavement construction in the United States and examines changes to accommodate increased traffic volume and loading on road projects. The history of the development of traffic on interstates and other major highways is discussed, and the sharp increase in traffic loads that has accelerated the deterioration of the interstate and primary highway system is noted. This degradation called for some sort of rehabilitation strategy to preserve the existing system, and thus ushered in a new era in highway construction that focused on maintaining the highway system through rehabilitation, resurfacing, reconstruction, and recycling. . Different types of concrete pavements are discussed, along with typical highway designs, and different types of road structures used in interstate and heavy-duty mainline systems are considered ¬. Typical designs used for major hubs, civil and general aviation airports are reviewed, and concrete pavements for container ports, parking lots and cargo terminals are also discussed. Equipment development over the past 30 years has brought about major changes in PCC road construction methods, increasing production to meet the needs of major road construction programs during this period. Design changes that improve the performance of PCC pavements are reviewed along with examples of innovative technology.

Conclusion

Progress made and ideas that can be considered established

• A survey of pavement conditions and the need for a central database appears to be an accepted goal.
• The need to establish pavement maintenance intervention limits and maintenance strategies is generally accepted.
• Preventing water ingress into pavement structures is an important design and maintenance requirement.

• Concrete overlays (thick and thin) continue to increase in value and reliability over older concrete and flexible overlays. This storage method is now widely used.

Unsolved problems

• Although this is important, few countries have a central database of pavement condition. This would be more easily implemented if cheaper and faster survey systems were available. Photographic (including video) and other automated electronic systems of pavement condition assessment need further research and development.
• Retrofitting of effective drainage structures for existing road structures requires further research.
• Detailed technical and economic studies are needed to determine the full potential of concrete pavement recycling options.

Necessary studies

• Creation of a central database of road pavement condition, problems and solutions and use of data;
• The most modern technologies for laying concrete pavements on road surfaces;
• Processing of concrete coatings;
• The role of roller compacted concrete for pavement rehabilitation.

ABBREVIATIONS

AASHTO  American Association of State Highway and

PCC  portland cement concrete

References:

1. C. R. Freeme, E. Otte, and M. F. Mitchell. The Economics of Pavement Type Selection. National Transport Commission, Pre· toria, 1980.
2.  M. F. Mitchell and R. N. Walker. The Economics of Pavement Type Selection. Proc., Third International Conference on Con- crete Pavement: Design and Rehabilitation. Purdue University, West Lafayette, Ind., 1985. pp. 23-32.
3. H . Liiwenberg. Betonstrassenbau: Stand der Technik. Strassen- und Tiejbau, Vol. 33, 1979. 12. T. Moss and H. Harbert. Grunderneuerung von abgiingigen Betondecken auf Autobahnen: Betonbauweise. Hochtief Nach- richten-Betonstrassenbau, No. 3, 1985.
4. V. Faraggi, C. Jofre, and C. Kraemer. Combined Effect of Traffic Loads and Thermal Gradients on Concrete Pavement Design.
5. Proc. , Workshop on Theoretical Design on Concrete Pavements, Epen, the Netherlands, Netherlands Centre for Research and Contract Standardization in Civil and Traffic Engineering, Ede, the Netherlands, June 5-6, 1986. 2. C. Kraemer. Test section in the CN-II (in Spanish). Proc. , First Meeting on Concrete Pavements, Barcelona, Spain, Catalonian Cement Manufacturers Association, December 16-18, 1981, pp. XIV-1-XIV-6.
6. Manual for Cement/Concrete Pavement. Japan Road Association, Tokyo, 1984.
7. The Status of the Nations Highways: Conditions & Pe,formance. Report of the U.S. Secretary of Transportation to 100th Congress, 1987.
8.  Ronald L. Hutchinson. NCHRP Synthesis of Highway Practice 99: Resu1facing with Portland Cement Concrete. TRB, National Research Council, Washington, D.C., 1982.