217-PRE : Progress of recycling in the built environment
Technical Committee 217-PRE
Activity ending in: 2012
Concerning the recycling of construction and demolition waste (CDW) important reports were prepared (TC-121-DRG, TC-165-SRM, TC-37-DCR). The last TC-198-URM directed by Prof. Charles F. Hendriks had to shorten its activity due to the unfortunate decease of the chairman. Its Final Report is essentially based on the tasks developed till November 2004 and the Proceedings of the International RILEM Conference organised by the TC (Barcelona 2004). Not precisely knowing the future plans of the chairman, the TC decided to end its activities. During the last meeting the participating members of the TC, together with Mr M. Brusin, identified several topics to be considered in the future and decided to support the proposal of E. Vázquez to create a new, probably larger, TC with renewed ideas to promote the progress of CDW recycling in construction.
In developed countries recycled aggregates are mostly used as sub-base in road construction. Recycled concrete aggregates are used, however to a lesser extent, in concrete. In studies, as well as in practice, encouraging results were obtained using recycled brick aggregates and recycled mixed aggregates in structural concrete. This practice is not accepted everywhere, mostly due to quality problems generated during the collecting of CDW and the production of aggregates.
In order to close the building cycle, recycled aggregates have to be used as much as possible in high-grade technical applications. From a technical and sustainable point of view, road construction cannot be the sole object for the reuse of recycled aggregates in the future. Due to their properties, end life products from road applications have less possibility for a second or third recycling turn than those from higher-grade technical applications. The TC will collect and analyse the most recent developments in this field. New applications of ceramic CDW such as application in lightweight concrete or precast concrete elements should be considered.
Quality assurance of new products obtained by processing CDW will be studied on the basis of existing and proposed new methods.
An important task to be realised by the TC will be the revision of actual and new tests in order to judge their effectiveness in reflecting the necessary properties.
The fine fraction ≤ 4 mm obtained by processing CDW presents problems for application. There is a need for information and research about how to use this fine fraction. Experience with use in products such as self-compacted concrete must be collected and stimulated.
During the Barcelona conference many contributions were presented by researchers from countries participating for the first time in recycling activities. The majority of these countries has to face numerous prejudices about recycling of CDW. The new TC has the intention to collect information on the actual situation in these countries. After analysing the results, the TC will suggest different solutions and tools allowing the technicians and producers to decide why and how recycling can be done. Besides, the TC will produce tools for education on recycling in construction and demolition.
Terms of reference
The main purpose of the new TC will be learning from each other and trying to induce progress on recycling of CDW. The starting point will be the work previously done by other RILEM committees, as well as collected practical experiences in different countries. The identification of gaps in the knowledge will be necessary to help overcome the obstacles and to promote research in a really effective way. In order to improve the quality and the sustainable use of the recycled products, it is necessary to review the actual tests and to analyse the proposed new ones.
Detailed working programme
Firstly, data and problems in different countries will be collected. Three categories of countries will be surveyed:
1. Countries that consider recycling as a matter of course;
2. Countries where recycling has started and is in progress; and
3. Countries that hardly do any recycling.
Furthermore, a review will be undertaken regarding the tasks of the past RILEM committees, existing guides and recommendations at national or international level, proceedings of conferences and published literature.
The TC will work on the following topics:
- Prepare a State of the Art on innovation in the field of CDW recycling. Promote higher-grade technical applications.
- Detect and analyse principal problems related with the quality assurance of the products.
- Review actual tests and analyse new tests for recycled aggregates and their products.
- Collect experiences and give suggestions for research on the use of the fine fraction ≤ 4 mm.
- Promote new applications for recycled ceramic aggregates.
If necessary, subcommittees will be established to address the above topics.
The proposed members are academics, researchers and potential users of recycled CDW. Special attention will be paid to the incorporation of recyclers representing the sector. In order to generate more information on these countries, an effort will be made to incorporate members from Canada, Russia, the United States of America and Japan, and also from countries where recycling has just started like Brazil and Egypt.
- A State of the Art report on innovations in the field of production and application of recycled aggregates and derived products.
- A Recommendation about the use of tests and quality assurance.
- A Guide helping to take sustainable and practical decisions in different contexts, analysing situations and perspectives, application of models if possible. The Guide will contain educational advice to develop a recycling friendly situation.
Another foreseen activity is an international symposium after four years of activity of the TC.
Group of users
Researchers, authorities related with construction, engineers and technicians designing or working in different construction fields, producers of concrete and precast concrete elements, recyclers and demolishers.
Specific use of the results
The results of the TC work will have application in planning the production of recycled aggregates, improving the quality, and helping to optimise the economy of the plants promoting the use of fines and recycled ceramic aggregates. Moreover, the results will support countries new in recycling to orientate their decisions. In general, the results will promote sustainability and technical progress.