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...... Changes to Aggregate Specifications and You can find out why, plus an overview of the changes in products and terminology on this page. We have produced a Product Converter to help you relate the new and the old product names. Please
click on one of our product categories below for a full list of
our product offerings. Why the change? In common with other harmonization throughout the European Union (e.g. metrification, passports etc), there are major changes to the way Asphalt Materials and Aggregates for the construction industry will be described and specified. The idea behind these extensive changes is to allow any member state to supply any other member state to a common standard. Whilst this may be impractical for the majority of Coated Materials, there are clear possibilities for the import/export of Aggregates. To this end, there has been a European Technical Committee comprised of representatives from all over the EU to oversee and development common standards. What changes? All British Standards relating to the composition of single sized aggregates, i.e. BS 63 and BS 882 are now superseded by European Standards EN 13043 (Aggregates for bituminous materials) and EN 12620 (Aggregates for concrete). In addition, a number of British Standards detailing various physical property test methods for aggregates are also withdrawn and replaced by EN standards, e.g. EN 933-1 replaces BS 812:103.1 for grading and EN 933-3 replaces BS 812:105.1 for flakiness determination. Regrettably, these are not direct replacements and the test methods have changed to fit within the new EN Standards. The composition standards (EN 13043 and EN 12620) contain a number of different aggregate size/grading category combinations and have been developed to apply throughout the whole of the EU. In simple terms, 14mm Single Size Aggregate, now denoted as 6/14mm aggregate can be classified with as many as 6 different grading categories. Obviously the quarrying Industry cannot produce an aggregate that will comply with all the various categories. Equally, associated with these grading are a vast number of physical/mechanical tests. Some of these tests are required for aggregate produced within the UK, such as PSV. However, tests such as the Nordic test for studded tyres are clearly inappropriate. Therefore to prevent any such confusion the UK has developed a series of Published Documents (PD) to accompany the EN Standards. These PD's clearly set out guidelines that indicate the specific requirements for the UK, i.e. specific grading tables applicable to both bituminous and concrete aggregates together with their associated physical and mechanical test requirements. Reference must always be made to the PD when selecting or specifying a UK aggregate. Changes to Terminology Perhaps the most difficult aspect of the changes are the changes to terminology of aggregates and asphalt materials. We currently use terms such as 14mm single size, 10mm single size and 20mm-5mm according to the relevant British Standard. The new EN's no longer refer to "single size" aggregates but refer to the smallest and largest aggregates that are permitted within the selected size. In addition, under BS 63, there were two main options, Part 1 (routine roadstone aggregates) and Part 2 (surface dressing chippings), the difference being that aggregates specified to Part 2 were cleaner and less flake. Single size (and blended) aggregates are used in the manufacture of concrete and these are specified by BS 882.
Notes
Note that aggregates used for surface treatments (surface dressing chippings etc) have a size of 6.3/10 to distinguish grading requirements from routine aggregates. Asphalt Material Changes These are relatively straight forward at present, apart from some technical issues regarding correction factors, the descriptions fall in line with Euro requirements, e.g. 20mm Dense Binder Course 50pen is now 0/20 Dense Binder Course 50pen. Equally, a previous 35/14 HRA Wearing Course is now 35% 0/14m HRA Surface Course. 0/20mm or 0/14mm denotes that the material has a grading size profile of between 20mm and dust or 14mm and Dust. However, the major change was the deletion of ALL previous 40mm products including 40mm Dense Macadam’s, 40mm Binder Course, 40mm Heavy Duty and 40mm High Modulus Mixes. Equally, 28mm aggregate is now no longer an option, the nearest comparison being 32mm, which fits neatly mid-way between the old 40mm, or more accurately 37.5mm, and the 28mm size aggregate. A new set of Asphalt standards has been drawn up for use in the ‘EU’ these were published in the latter half of 2006 for implementation on the 1st January 2008. These standards include the following; EN 13108-1 - Material Specification for Asphaltic Concrete The two most common standards previously used in the UK were BS594 for Hot Rolled Asphalt; which was replaced with EN 13108-4, and BS 4987 for Coated Macadams; replaced with EN 13108-1. Agreed European Standard Test Methods for asphalt have been published by BSI as parts of BS EN 12697 over the past several years as the EN 13108’s were completed. Before these Standards can be implemented, however, there is a need for National Guidance Documents (PD) on both BS EN 13108 and BS EN 12697 to be produced to explain their application in the UK context. There is also a need to produce a revision of Parts 2 of BS 4987 (Asphalt Concrete/Coated Macadam) and BS 594 (Hot Rolled Asphalt) to bring asphalt laying requirements and guidance in line with the European Standards. These various documents are currently being prepared with availability anticipated by the end of 2006 - early 2007. It has been agreed by the BSI Committee for asphalt (B510/1) that the whole package of European Specifications and Test Methods for asphalt, together with the National Guidance Documents and revised standard for asphalt laying should be implemented on 1 January 2008, which is the latest permitted date for implementation of the European Standards and withdrawal of conflicting National Standards. In the interim, the UK asphalt industry and highway authority organisations will be working hard to ensure that, during 2007 all in the UK having dealings with asphalt are brought fully up to speed with the new standards and that all documents that call up asphalt specifications and test methods are amended, as necessary, to ensure the smoothest possible implementation of them on 1 January 2008. |
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