Relation between CEN standards and performance based operations By JP Michaut Colas’ Group
What are the raised issues by the implementation of the European standards for aggregate and asphalt concrete in tendering ?
Asphalt concrete WG 1 /TC 227 meeting in Berlin
What asphalt standards ? The figures 7 European product standards ð 1 Reclaimed asphalt standard ð 1 Type testing standard ð 1 Factory production control standard ð 43 test standards ð
European asphalt standards è Asphalt Concrete è Very Thin Asphalt Concrete è Soft Asphalt è Hot Rolled Asphalt è Stone Mastic Asphalt è Porous Asphalt 13108 -1 13108 -2 13108 -3 13108 -4 13108 -5 13108 -6 13108 -7
European asphalt standards è Reclaimed asphalt or so called RAP è Type testing è Factory production control 13108 -8 13108 -20 13108 -21 è and one new European standard for Ultra Thin Asphalt Concrete (BBUM) ?
Asphalt concrete è From thin asphalt concrete to EME, from dense bitumen macadam to HDM and HMB and other AC (from 4 to 15 cm thick by layer) è One only standard for base, binder and wearing courses è 2 approaches: empirical or fundamental For the other standards è One empirical standard per product
Empirical or fundamental ? è Empirical = recipe Ä Performances related specifications (rutting) è Fundamental = stiffness modulus, fatigue and triaxial Ä Performances based specifications Ä But may be we can speak just about performance and specification
What content ? è General requirements (grading, void content, water resistance, rutting, etc. ) You can choose è Empirical (range for grading, binder content, Marshall only for airfield, void filled with binder, etc. ) You can choose è Fundamental (modulus, resistance to permanent deformation by triaxial test, fatigue) You can choose è But do not forget that european standards does not take into account laying.
Fundamental approach n One specification is the minimum binder content è n greater than 3 % One other is the limit of target composition è range for main sieves (1. 4 D, D, 2 mm, 0. 063 mm)
n n With fundamental approach, you can propose design alternative by using the real mix performances such as stiffness and fatigue But we must have performances for all mixes
What changes due to type testing? Type testing or how to prove that asphalt concrete meets standard requirements
n n A single mix formulation is valid for 5 years except if changes in aggregate (category, particle density, etc. ) or in bitumen Laboratory validation Production validation or or Production and laboratory validation n List of tests per product to carry out to demonstrate standard conformity n One test for one property
What changes due to the factory production control ? Ø Systematic production control Ø More or less control for certain mixing plants
Factory production control è Based on quality assurance (ISO 9001) è Based on detailled analysis of the mix è Depending of non conformities (figures outside tolerances), level of minimum frequency for analysis of finished product è Level fo frequency fixed by the standard (more or less numerous) è Guide for audit by notified body is in the standard
Before works, you have to prove that your mix meets the standard requirements: this is type testing n During works, you have to check asphalt manufacturing : this is factory production control (loose mix) n But for laying, you have to prescribe the controls or the performances you want : this is the contract. n
To conclude for asphalt En asphalt standard will be published in April 2006 n Withdrawal of all national asphalt standards in December 2007 n You have to write your national forewords and also may be a guide to describe your choice n
And for aggregate Already applied since July 2003 Withdrawal of national standard Since June 2004 Just one only standard
Four parts 1. 2. 3. 4. Aggregate characteristics and specifications Initial type testing or How to prove that the aggregates meet the standard requirements Factory production control And a national foreword
Characteristics and specifications n Sieve sizes (3 possibilities) Basic set, basic set + set 1 or basic set + set 2 n n Grading Choice of physical or manufacturing characteristics and choice of specifications or not
Initial type testing n n n For a new source Major change in the nature of the raw materials or in the processing conditions But in fact, tests used are those for factory production control
Factory production control Based on quality assurance n Minimum test frequency are specified, examples: n è Grading: one per week and per size è Shape of coarse aggregate: one per month n And one audit by notified body
What differences ? n n n Grading : perforated sieves and not wire sieve (adaptation or interpretation issue ? ) Example: 4/6. 3 mm control (1. 4 D) or 8. 82 mm Close sieves in set 2 are 8 and 10 But ISO 565 , R 20 set: 9 mm ? Then which one to choose ?
But are they ? 1. 2. 3. 4. 5. Well known asphalt concrete formulation Keep the same composition (x% of each constituant) Grading curve with perforated sieve New grading curve But always the same formulation and composition Wide grading : no difference Narrow grading : light difference You have to do your own experience
But also some difficulties n n n Measurement of aggregate particle density before and after: not the same results Some standards are already reviewed due to mistake, difficulty for performing test, etc (in progress) Conformity criterias are missing
Positive and negative effects !!! In Europe, we will speak the same language and we will use the same test methods (PE) n Each mix has to be checked every 5 years (PE) n Each mix of each mixing plant has to have a type testing (PE) n Factory control more efficient based on regular frequency production (PE) n
Positive and negative effects and others !!! Difficulty to understand european standards and hence the need to have a national foreword (NE) n Need a fundamental approach for each product (porous asphalt, SMA, etc) n Need to describe the performances for laying (in terms of compacity or others) n
To conclude n n n En asphalt standard will be published in April 2006 Withdrawal of all national asphalt standards in December 2007 Writing of national forewords in progress for certain countries And good luck for implementation in your contracts
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