QPA Aggregates Group Bulletin6 Type 1 granular …

1 IntroductionBulletins 1 to 5 of this series of informationsheets gave an introduction to the changes thatproducers, specifiers and users of aggregatesneed to be familiar with since the adoption ofEuropean Standards on 1 January situation for Type 1 granular sub-base isslightly different. Type 1 is considered to be anunbound mixture of Aggregates , rather thansimply an aggregate . It could be described asbeing like an asphalt mixture (but without anybitumen) or a CBM (but without any cement).It is therefore outside the scope of EuropeanStandards for Aggregates and is coveredinstead by BS EN 13285:2003, Unboundmixtures - is currently no National Guidance in theUK for BS EN 13285. This document thereforehighlights key points of the standard and makesrecommendations for its application in the European Standard applies to unboundmixtures and includes Aggregates fromnatural manfactured and recycled sources. Inthe UK BS EN 13285 applies to granularsub-bases and cappings with the requirementsof the standard for the relevant materialproperties cross-referenced to BS EN 13242: Aggregates for unbound and hydraulicallybound information on BS EN 13242 is givenin Bulletin 5 of this British Standard is superseded byBS EN 13285 and prior to 1 January 2004 therequirements for Type 1 were given in theSpecification for Highway Works (SHW).

2 BS EN 13285 significantly extends the existingrequirements for Type 1 and the SHW has beenrevised to specify Type 1 and other unboundmixtures in accordance with BS EN that the revision to SHW has changedthe material descriptions for capping. Thedesignations 6F1 and 6F2 are now reserved formaterial excavated from within the fine graded and coarse gradedcappings are now designated 6F4 and requirementsAggregates used in Type 1 and other unboundmixtures must conform to the requirements ofBS EN 13242 for crushed, broken and totally rounded particles resistance to fragmentation (Los Angeles on the 10/14 fraction) magnesium sulfate soundnessResistance to wear (Micro-Deval on the10/14 fraction) and water absorption mustbe declared on request. There is norequirement in the UK for the otherproperties given in BS EN 13242 for naturalaggregates. Some additional requirementsmay be necessary for manufactured andrecycled DesignationUnbound mixtures are described in terms of d/D , where d, the lower sieve size, is alwayszero,and D is the upper sieve size.

3 The mixturedesignation of Type 1 (and Type 2 and 6F4capping) is 0 EN 13285 emphasises consistency andcontinuity of gradings within the overallgrading limits. It achieves this throughrequirements over and above a simple gradingenvelope. The supplier must declare a typicalgrading for his unbound mixture within arelatively narrow band, and then work totolerances about that declared grading withinthe overall grading limits. Furthermore, thedifference in the percentage passing adjacentsieves must be not too little and not toomuch ,again with defined limits, to ensuregrading continuity. The overall limits, bands fordeclared gradings, tolerances and differencesare specified by grading can be seen from the new gradingrequirements for Type 1, there is anappreciable oversize allowance whichconsequently allows the material toapproximate to the existing Type 1 contentBS EN 13285 gives requirements for thepercentage of material passing the There are maximum and minimumrequirements.

4 It is recommended that theexisting UK practice is maintained and that norequirement is specified for the minimumfines oversize allowances are availablefor unbound mixtures. For Type 1 (and Type 2 Type 1 granular sub-baseand other unbound mixturesImplementation day 1 January 2004 INFORMATION ON NEW EUROPEAN STANDARDSAGGREGATESQPA Aggregates Group Bulletin6and 6F4), a minimum of 75% must pass sieve. This goes some way toexplaining how a mixture designation of 0/32can be roughly equivalent to a materialformerly specified as requirementsBS EN 13285 permits the use of nationalregulations to control frost heave andpermeability. This means that in the UK, thefrost heave test (BS 812: Part 124) and theplasticity index test (BS 1377: Part 2) are stillrequired for Type standard also requires declaration of drydensity, optimum moisture content and water-soluble sulfate content when markingThe product standard sets out a mandatorysystem of factory production , it does not necessarily provide for allthe essential requirements of the ConstructionProducts Directive and is not Type 1 and other unbound mixturescannot be CE bulletin sheet does not replace therelevant product standard - BS EN 13285 -and aims to give introductory informationonly.

5 Further information can be obtained fromQPAat the address EN 13285: 2003 Unbound mixtures - SpecificationBS EN 13242: 2002 Aggregates for unbound and hydraulicallybound materials for use in civil engineeringworks and road constructionAll documents are available fromCustomer Servicesat British StandardsInstitution389 Chiswick High Road London W4 4 ALTel 020 8996 9001 Fax 020 8996 7001e-mail of a European Standard specification for Type 1 made from crushed rocknatural aggregateRequirements for Aggregates used in the Type 1 Sample SpecificationCrushed, broken and totally rounded particlesC90/3 Resistance to fragmentationLA50- Los Angeles coefficient, 10/14 fractionResistance to wearMDENR, value to be declared-Micro-Deval coefficient, 10/14 fractionMagnesium sulfate soundness MS35 Water absorptionWA24NR, value to be declaredAll other BS EN 13242 requirementsCategory NR (no requirement)Property BS EN 13242 categorySieve size (mm)Percentage by mass passingSummary grading requirementsGrading shall conform to BS EN 13285 designation 0/32 GP,maximum fines UF9,oversize OC75,as summarised the 63, and sieves there is only a requirement to comply with the overall grading Supplier declaredTolerance on thegrading range value grading bandsupplier declared - 1001643 - 81 54 - 72 15823 - 6633 - 52 15412 - 5321 - 38 1526 - 4214 - 27 1313 - 329 - 20 0 - 9 Grading of individual batches - differences in values passing selected sievesPercentage by massRetained sieve size (mm)Passing sieve size (mm)Not less thanNot more than81673048730 Other mixture requirementsThe Type 1 shall not be frost size fraction of the Type 1 passing a test sieve shall be example of a European Standardspecification for Type 1 made from crushedrock natural aggregate is shown below.

6 Notethat different aggregate , grading and mixturerequirements would apply to Type 2, 6F4, 6F5and other sub-base and capping trade association for the aggregate , asphalt and ready-mixed concrete industriesProviding Essential Materials for Britain156 Buckingham Palace Road London SW1W 9TR Tel 020 7730 8194 Fax 020 7730