Centro de Estudios de Carreteras

The Centro de Estudios de Carreteras has engaged itself, during the year 2001, in activities of experimentation, applied research, specialised technical assistance and standardisation. These activities have occurred in all the different fields of the road engineering technical domain: Placing of bituminous layers in the Full Scale Test Track pavements, includin...................g.

The Centro de Estudios de Carreteras has engaged itself, during the year 2001, in activities of experimentation, applied research, specialised technical assistance and standardisation. These activities have occurred in all the different fields of the road engineering technical domain: pavements, including its constituent materials, its structural assessment and design, and the study and evaluation of its surface characteristics; road equipment; measuring of traffic and road safety.

Public administration, public agencies and entities, as well as private enterprises, interested in the field of roads, have been the recipients of the different works carried out by the Centro de Estudios de Carreteras. Of particular note, among the first group of recipients, is the Directorate General of Roads (DGR) of the Ministry of Fomento, and with a growing specific weight, the road organisations of the Regional Administrations in Spain; other examples include the European Union and Public Entity Puertos del Estado; finally, the activities developed for the private sector have primarily focused on the manufacturers of pavement materials.

Placing of bituminous layers in the Full Scale Test Track

The LABORATORY OF ROAD INFRASTRUCTURE deserves special mention for the planning and the start of the construction of the pavements to be tested in the Full Scale Test Track on six different types of subgrade for the Directorate General of Roads (DGR). This test represents a continuation of the previous one on subgrades, where significant results in the field of appropriate solutions for subgrades in critical zones were obtained. Results were particularly applicable to those presenting water-related problems where solutions based on either lime stabilizations or insertion of geotextiles performed excellently. In the coming test, variations of the thickness of cement stabilized soil and soil with high bearing capacity (CBR = 20) on different types of soil will be assessed. In addition, four different layers of wearing courses including two types of stone mastic asphalt (SMA), a porous asphalt with a very high content (>25%) of interconnecting voids and a cold micro-asphalt, are planned to be tested in the curves of the Full Scale Test Track. The final report on the previous test, and an additional one on the design and construction of these new sections, were edited during 2001. The beginning of the new test is expected to happen in February 2002.

The survey of highway pavements, whose main objective was the determination of the performance of the pavement sections referred to in the Spanish Code 6.1 and 2 IC for Pavement Design and intended for heavy traffic, has been completed. These results may be taken into account in future versions of the code. The surveying campaigns, which are performed annually, are executed with an average of every three years for each type of pavement since the expressways of the National Road Network, built after 1987, include about 2000 km of flexible pavements, 3000 km of semirigid, and 800 km of rigid ones. The report on rigid pavement from inspections, for the Regional Department of Asturias, as well as the summary document for this type of pavement in the whole National Road Network, was prepared during 2001. On the other hand, work on the inspection and analysis of pavements has continued, having been assessed the performance of the Zuzones-Vadocondes section in the N-122.

Diagram of the pavement sections used in the new test in the Test Track

Pavement recycling techniques have represented another important area of study. A report on the performance of pavement cold-recycled with emulsion in road N-525, in the province of Zamora, has been published. This document presents the history of the road section pavement, the mechanical characterization data of its recycled material, and the corresponding analysis of performance.

The activities developed for Public Entity Puertos del Estado belong to a different framework. Reports on the ports of Vigo and Pasajes, corresponding to the new assessment of port pavements designed according to ROM 4.1-94, were edited.

Works on the monitoring of port pavements for the 2001/02 campaign have been carried out, with the objective of developing an inventory of existing pavements in the main Spanish ports as well as data gathering for a future updating of ROM 4.1-94 "Design and Construction of Port Pavements".

The Road Departments of several Regional Administrations have been recipients of work developed by the Laboratory of Road Infrastructure. A project for the Regional Government of Balearic Islands has been completed. This project established the equivalence between pavements with dry bound macadam layers and those referred to in the Spanish Code 6.1 and 2 IC. Compliance with the code criteria being necessary for the execution of road projects in the Balearic Islands when in co-operation with the Ministry of Fomento. The use of macadam pavement is quite accepted in this region, reaching a good performance level, even though it has eventually disappeared in the Peninsula. An agreement with the Regional Administration of País Vasco has been launched to co- operate with the drafting of a technical standard on pavement design, which will conceivably be ready in the year 2003. This agreement includes, in a special way, the prescriptions for the use of blast furnace slag as materials for road pavements. Last, but not least, it is important to mention the study of the Plan Cervo works for Concello de Cervo.

Technical assistance during construction of Highway 407 in the Toronto ring road (Canada)

The analysis of the method established in the draft European Standard prEN 13286-45 on the determination of the workability time of cement-treated materials and their application to Spanish conditions has been carried out for the Spanish Institute of Cement and its Applications (IECA). This study includes the analysis of the method and factors that influence the results, paying special attention to the type of cement, the water/cement ratio, the type of aggregates, and the use of retarder. The final report includes a proposal for a UNE standard for the execution of the test. As a second work carried out for IECA, the Laboratory of Road Infrastructure is co-operating in the preparation of, in co-operation with IECA technicians and an ad-hoc sector expert committee, to produce a "Manual of Materials Treated with Cement". The Centre has taken responsibility for the technical management and the manual is planned for completion by the middle of 2002.

Furthermore, several works, which could be grouped into three categories, have been executed for private enterprises. First is the works carried out in the field of road pavement materials such as the characterization of asphalt emulsions, for Asfaltos Naturales de Campezo; the determination of the polymer presence in a binder, for Enmacosa; the study of paval as added filler in hot bituminous mixtures, for Collosa and Valcritec; the determination of the SHRP grade of two bitumens, for Repsol Petróleo; and the study of binder retention in two different types of geotextiles, for Polyfelt. The technical assistance to road work activities would represent the second category of activities carried out, such as the testing of bituminous mixtures in the Fraga by-pass, for Fraga UTE, and the technical assistance in relation to motorway 407, the Toronto by-pass in Canada, for Ferrovial-Agromán Construcción. The third category groups together the studies on the projects for specific road sections, such as the rehabilitation proposal of the precast concrete block paving for the Centro de Transportes de Coslada and the alternative pavement design for the extension of the semi-detatched dock in the Port of Barcelona, for UTE Muelle Adosado.

Bitumimous Binders Forum. Correlation between the strain speed of the mixture and the softening point of the binder

The Centro de Estudios de Carreteras has continued the self-funded research and development work in the framework of the Forum of Bituminous Binders, on the influence of bituminous binders in the permanent deformation of asphalt mixtures. The study has mainly focused in the execution of the tests to correlate the bitumen properties with those of the bituminous mixtures, in the field of permanent deformations. This work has been carried out in cooperation with many companies of the sector (Repsol, Proas, BP, Nynas, Probisa, Elsan, CIESM).

The AREA OF FULL SCALE EVALUATION has maintained its co-operation with DGR of the Ministry of Fomento in the field of surveying the skid resistance in the National Road Network, continuing with the systematic yearly field campaigns for the measurement of the side-way force coefficient in the eastern part of the Peninsula. These works are of particular relevance in order to identify those zones with low skid resistance, enabling the programming of particular road surface rehabilitation activities with positive impact on road safety. In this particular aspect, a test case to evaluate the influence of the average speed in the determination of the side-way force coefficient has been carried out. This study, executed on the most representative types of pavement in the road network, will allow an increase of measuring equipment speed (for those of CEDEX as well as DGR), which will lead to an increase of performance and road safety in those sections where traffic demands a higher flow speed. On the other hand, the training of the DGR staff has continued in co-operation through the courses on inspection, surveying and maintenance of pavements.

Once the FILTER research project on measurements of longitudinal and transverse evenness of road pavements has reached its conclusion, the results of the work carried out by the CEDEX on the longitudinal evenness indexes obtained from the international test case, as part of the project, have been disseminated through papers presented in the TRB (Transportation Research Board) Congress, held in Washington, and the World Congress of the IRF (International Road Federation), held in Paris.

A Catalogue of Residues Used in the Construction Sector has been elaborated, in cooperation with the Laboratorio Central de Estructuras y Materiales and the Laboratorio de Geotecnia, for the Directorate General of Environmental Quality and Evaluation of the Ministry of Environment.

Port pavement management system

The exploitation and analysis of the systematic database of the visual surveying of port pavements, from the campaigns corresponding to previous years, has been carried out for the Public Entity Puertos del Estado, obtaining the average characteristics of the constitutive materials of the port pavements, as well as their performance.

De-icing chemicals spreading (CMA-Calcium Magnesium Acetate) on a road in the Ordesa National Park

The study of an environmentally friendly strategy for road winter maintenance has been developed for Ordesa and Monte Perdido National Park. The study and analysis of two preliminary plans corresponding to two roads in Nicaragua has been conducted for the Instituto de Crédito Oficial (ICO).

The 2000-2002 weigh-in-motion campaign for the National Road Network has represented the principal activity of the AREA OF TRAFFIC AND ROAD SAFETY. Data have been collected, during 2001, at 24 scale stations installed in different sections of the highways, motorways and expressways managed by DGR of the Ministry of Fomento. This data collection includes traffic parameters such as traffic volumes, speeds, types of vehicles, and, specially, the vehicle loads and specific axle loads.

Obtaining a precise and non-biased knowledge about the real traffic and loads acting on road pavements represents the main purpose of these weigh-in-motion campaigns. The weigh-in-motion procedure is the only technique capable of collecting all this information at a reasonable price, and allows the measurement of vehicle loads on the road without causing any interference in the traffic. In addition, it is meant to study certain aspects of the road transport during the current campaign, which makes the collection of data from all vehicles dedicated to this activity necessary, including light vehicles (commercial light vehicles, vans and light trucks) and the heavy ones (already included in previous campaigns).

The study and analysis of road equipment (safety barriers, fixed and variable message signs, road lighting and tunnel safety systems) is the other activity in which the Area of Traffic and Road Safety focuses its efforts. It attempts to both determine the characteristics of the equipment, in order to fulfill the specifications for which they are meant to be, with a view to their standardization, and assess the road safety and traffic effects.

The STANDARDIZATION AND REGULATION activities developed by the Centro de Estudios de Carreteras have primarily focused on the framework of the Spanish Association for Standardisation and Certification (AENOR), taking part in the elaboration of UNE standards inside the technical committees CTN 41 "Construction", CTN 51 "Oil Products", CTN 135 "Traffic Signs Equipment", CTN 146 "Aggregates" and CTN 159 "Road Transport and Traffic Telematics" and, in the field of certification, as part of the technical committee CTC 059 "Aggregates Certification" and the Advisory Board for the Certification of Construction Companies.

Axle load frequency histograms obtained at a weigh-in-motion site

At European level, the Centre has participated in ad hoc working groups belonging to the European Standardisation Committee (CEN) technical committees TC 226 "Road Equipment" and TC 227 "Materials for Roads". Also inside the regulation field, the analysis of the design life of the elements of structural concrete, with a view to its application in the Spanish Code for Structural Concrete EHE, has been finalized, in cooperation with the Laboratorio Central de Estructuras y Materiales of CEDEX, for the Technical Secretariat General of the Ministry of Fomento, while the elaboration of the White Book of Concrete has continued.

Some of the friction measuring devices (from right to left), equipment of LCPC (France), DWW(The Netherlands) and CEDEX involved in the HERMES Project

A variety of international research activities has become an important part of the activities in which the Centre has participated. Within the FEHRL (Forum of European National Highway Research Laboratories) framework, the Centre has specifically contributed in the HERMES project, being the European harmonisation of road pavement measurement on skid resistance and texture. A calibration test experiment was executed in Valencia, during the month of November, with the participation of several European friction equipment, as well as one of CEDEX.

Within the COST (European Cooperation in the Field of Scientific and Technical Research) framework, the Centre has actively participated in COST Action 343 "Reduction of Road Closures by Improved Pavement Maintenance Procedures" and COST Action 347 "Improvements in Pavement Research with Accelerated Load Testing". Finally, within the PIARC (World Road Association) scope, the Centre has participated in two technical committees: CT1 "Surface Characteristics" and CT6 "Road Management".

Monographic article

The role of CEDEX in the utilization of waste materials in road construction

A growing commitment to preserve the environment, while making it compatible with both the social and economic development, exists at an international level. It is in this particular sense that the concept "Sustainable Growth" has been adopted as "that sort of development capable of satisfying the present needs without endangering the coming generations capacity to satisfy their corresponding needs" (Report of the United Nations Commission on Environment and Development, 1987).

Electric Arc Furnace slags (EAF-slags)

The Rio Declaration, approved in the United Nations Conference on Environment and Development held in 1992, introduced the term "Sustainable Development" as a principal element. The Conference also attached to this term a great political significance as it was supported by a solid set of Principles and an Action Programme that compound an operative framework for the development and instrumentation of a worldwide environmental politics. The European Union has introduced the idea of sustainable development in the Treaty of the Union (art. 2) as an inspiring objective of every Member State for their social and economic regulations. In June 2001, the European Counsel of Gothenburg approved the Strategy for Sustainable Development in the European Union. In Spain, the Government has decided to promote this process through the preparation and starting of a Spanish Strategy on Sustainable Development for the next 25 years.

Public works represent a fundamental factor for the impulse of development in every country. Technical considerations, as well as economic, social and environmental related ones, must be taken into account in the planning, design, construction and exploitation phases of every public work. Linear works, as a particular type of the public ones, usually show an associated environmental impact, as a consequence of their particular characteristics. In addition, this type of works requires important quantities of material mostly from natural sources -gravel pits and quarries- which cause a gradual degradation to the physical environment.

On the other hand, a growing concern about the adequate management of waste materials from the production -industry, agriculture and energy- and residential sectors exists nowadays at an international, national, regional and local level. In Spain, the Parliament Act 10/1998, dated 21st April, on Waste Materials adapts Spanish Law to the new perception of the waste materials policy in the European Union and "attempts to contribute also to the protection of the environment, coordinating the waste materials regulations with the economic, industrial and territorial ones, with the purpose of both stimulating the reduction of its generation and prioritising the re-utilisation, recycling and appreciation of the waste materials over other management techniques".

In situ recycling of asphalt pavements

The Act 10/1998 establishes that the National Administration will develop several National Waste Materials Action Plans, grouping together the corresponding Regional Plans and setting out the specific objectives for reduction, reutilisation, recycling and any other way of appreciation and elimination of waste materials. Nowadays, the Council of Ministers has already approved some of these national action plans, being of particular note the National Action Plan for Construction and Demolition Waste Materials 2001-2006 (BOE 12/07/2001) and the National Action Plan for Scrap Tires 2001-2006 (BOE 30/10/2001).

Example of a front page of a Technical Card of Waste Material Utilization

The Centres and Laboratories of CEDEX, have actively participated in the environmental impact assessment of public works and the corresponding corrective actions to reduce these impacts. Furthermore, many waste materials characterisation studies have been carried out in order to encourage the use of these materials in public works. During the last twenty years the Centro de Estudios de Carreteras has carried out studies on the utilisation of certain waste materials in road pavements and upper layers of subgrades, as well as on the recycling of materials from existing deteriorated pavements in pavement rehabilitation projects. These works have been executed under cooperation agreements with industrial enterprises and public institutions (both national and regional) and the active participation in national and international fora and working groups.

A great number of studies on the characterisation and utilisation of basic oxygen furnace slag, and crystallized and granulated blast furnace slag in pavement layers were carried out during the 80s and 90s for ENSIDESA. The technique for the utilisation of the "slag-slag" material was also developed. Studies on the applications of colliery spoil in road pavements started at the beginning of the 90s, lasting the whole decade, for HUNOSA. In addition, during all this time, numerous applications of waste materials have been studied, being of important note the following: plastic waste materials in the Novophalt material; used motor oil as partial substitution of road bitumen; plastics, textile fibres and cellulose in bituminous mixtures; dregs of olive oil and tire rubber in different applications. Several works have been carried out in the area of road pavement recycling for Directorate General of Roads (DGR) and some motorway concessionaires: establishment of the methodology and guidelines for the study of bituminous mixtures recycled in laboratory; drafting of proposals for the technical prescriptions on recycled materials; execution of characterization studies of different binders used in recycling of bituminous mixtures; monitoring of many works in roads where the pavement had been in situ recycled with cement, cold recycled with emulsion or hot recycled.

CEDEX has either organized or participated, in cooperation with different public and private organisations, in a great number of conferences and seminars on the utilisation of waste materials in road construction. Among these, it is important to mention, within the framework of the SPRINT European Programme, a congress held in Barcelona in April 1994, and one-day seminars in Madrid, in March 2001, and Pamplona, in June 2001. At the moment, CEDEX is cooperating with the Directorate General of Environmental Quality and Evaluation of the Ministry of Environment in the execution of different technical assistance works. Of important mention among these works is the elaboration of studies about the potential use of certain waste materials in civil works, being carried out jointly by the Centro de Estudios de Carreteras, the Laboratorio Central de Estructuras y Materiales and the Laboratorio de Geotecnia. The recently finalised "Catalogue of Waste Materials Used in the Construction Sector", including detailed information about fourteen waste materials with potential use in public works that either have been or have possibilities to be used in Spain, has been the result of a coordinated effort among the above mentioned centres of CEDEX. The document is meant to be a useful tool for potential users and producers of waste materials in the construction sector, and technicians and legislators implied in the appreciation process. For every waste material, a Technical Card of Utilisation, containing general information (name, picture, origin, national production and geographic distribution), and also technical data (possibilities of appreciation of the waste materials in construction, processing, waste materials and processed material properties, environmental considerations and applied technical regulations in the utilisation of the particular waste material) has been created. Every card also includes several reference lists: national and international public works where the waste material has been used, reference publications and institutions of interest capable of providing information and know how about the waste material.

The Catalogue provides a national and international overview of the waste materials recycling state-of-the-art in the construction sector. Taking into account the dynamic changes in the sector, as a consequence of the continuous research effort and its corresponding industrial implementation, the Catalogue will be updated on a regular basis. Once the Catalogue has been finished, the Centro de Estudios de Carreteras of CEDEX is currently working on the preparation

www.cedex.esof a http://mahdihashemi.blogfa.com/"Guide for the utilisation of waste materials in road construction".