Mixtures – How to Specify Them Andy Simms Jacobs Laboratories London Asphalt Specification ( Makes the following simpler!) 1 Idealised Pavement Structure (Flexible or Flexible Composite) Road Surf ace Pav ement Surf ace Course Binder Course Surf acing Sub Base Formation Lev el Capping Lay er Foundation Base Sub grade Specification for Highway Works 2 British Standards – pre January 2008 PRODUCT STAND ARD LAYING STANDARD 3 HAPAS Certificate HAPAS - Highway Authorities Product Approval Scheme • New Materials including Thin Surface Course Systems • Proprietary systems, e.g. Masterpave, Axoflex, Durapave • Specified through SHW Clause 942 • Approval through BBA • Two year guarantee Asphalt Standards and Specifications y BS asphalt standards that you use in all contracts were changed on 1 January y All the laying standards and BS test methods also changed on 1 January. y Specification for Highway Works has also been revised (IAN101 & IAN102). 4 Why? - Principles of European Standards yHarmonisation of individual countries specifications and test methods yElimination of barriers to trade BS EN’s have greater authority/legal standing than current BS’s yThe European Standard brings compliance and conformity in to the standard yEnforcement is a trading standards issue Asphalt Product Standards 7 standards covering the products 1 standard covering Recycled Asphalt 2 standards covering Factory Production Control (QA) (44 Standards covering test methods) 5 The EN 13108 Family of Standards - Products y BS EN 13108-1 Asphalt Concrete y BS EN 13108-2 Asphalt Concrete for Very Thin Layers y BS EN 13108-3 Soft Asphalt (Nordic countries) y BS EN 13108-4 Hot Rolled Asphalt y BS EN 13108-5 Stone Mastic Asphalt y y BS EN 13108-6 Mastic Asphalt BS EN 13108-7 Porous Asphalt The European Standards for Asphalt y Properties and other parameters y y Product Identification Attestation of Conformity − categories selected from tables − Includes recipe and performance related testing − EN 13108-20 Initial Type Testing − EN 13108-21 Factory Production Control [FPC] what we call QA y CE Marking 6 On request All the key information required by law EN Standards - Important Differences from BS y y y y y ENs relate to the product….“in the back of the lorry”, but some properties are installation dependent (BS 594987) Some description changes - mixtures prefixed by an abbreviation of their type: AC, HRA, SMA − e.g. 14 SMA surf 40/60 Some test method changes e.g. Wheel tracking instead of stability Formalised specification of reclaimed asphalt in BSEN13108-8 Changes to compliance ‘Q’ values (Operating Compliance Level) 7 UK Guidance Documents PRODUCT STAND ARD y PD 6691 – the EN 13108 family of asphalt mixtures applicable to the UK y PD 6692 - the EN 12697 family of 44 standards covering the testing of asphalt mixtures. PD 6691:2007 y PD6691 has been drafted in a format which is similar to BS 4987-1 & BS594-1. y PD6691 contains detailed guidance on EN13108 Parts 1, 4, 5 (material specific requirements), 20 & 21 (Attestation of Conformity) y PD6691 Annexes contain stand-alone example specifications for all commonly used asphalt mixtures. y Requirements for Type testing (Protocols in BS594987) 8 Requirements for Type Testing y y y Ac Properties (Design Void Content, deformation resistance) Performance HRA properties (voids, resistance to permanent deformation) SMA Binder Course properties (voids, resistance to permanent deformation) PD 6691:2007 Example Mixture Specifications Annexes B - Asphalt Concrete C - Hot Rolled Asphalt (incl. Coated Chippings) D - Stone Mastic Asphalt (Not TSCS) 9 How to build a description Asphalt type AC SMA HRA Size ‘D’ mm 2 6 10 50/10 14 50/14 20 50/20,60/20 32 60/32 Course type SURF BIN BASE Binder Grade 10/20 30/45 40/60 PMB 70/100 100/150 160/220 One from each line is essential HRA Surface Course Descriptions Material type HRA 0/2 F or C 15/10 F Stone content/size ‘D’ 30/10 55/10 30/14 F F or C F or C Course type 35/14 F or C 55/14 F or C surf Binder grade 30/45 rec 40/60 70/100 Mix type des PMB 100/150 perf 10 Typical Descriptions; additional UK detail y All the information goes into the designation −AC 32 HMB base 30/45 [30/45 = pen grade ] y PSV of the aggregate can be used in the UK mixture designation - not mandatory in the EN’s −AC 10 close surf 100/150 PSV60 −SMA 10 surf 40/60 PSV65 −HRA 35/14 F surf PMB des [ des = design mix] PD 6691:2007 - Nomenclature. 11 Some standard AC designations and binder grades A wide choice of binder is available Mixture Summary – HRA 12 Mixture Summary – SMA • For full document see http://www.qpa.org/downloads/asphbulletin02.pdf What about Laying? BS 594987: 2007 Transport, Laying & Compaction 13 BS 594987 y y y y y y y y y Combination of BS594-2 & BS4987-2 y Mi xture Approval / Type testing Protocols Covers all EN 13108 asphalt mixtures found in PD 6691 Min and max compacted thicknesses Accuracy of finish Improved clarity on la ying, formation of joints etc. Application of Coated Chippings and Rates of Spread Measurement of Texture Depth Compaction Sampling and testing for assessment of compacted asphalt Specification for Highway Works 14 http://www.standardsforhighways.co.uk SHW 900 Series IAN101/07 (revision Feb 08) • New Asphalt Standards • Good opportunity for a “Spring Clean” • New requirements to improve durability 15 Laying asphalt for greater durability 900 Series in summary • Clause 901 Bituminous Pavement Mixtures • Clause 903 Placing and Compaction of Bituminous Mixtures • Clause 920 Bond Coats, Tack Coats and Other Bituminous Sprays 16 Improved clarity for Clause 901 and 903 y y y Clause 901: Requirements for − Aggregates − Bitumen − Aim to avoid undue repetition in individual material clauses Clause 903: Clarify the requirements with respect to laying particularly those affecting pavement durability Requirement for Method Statements y Already included in Sector Scheme 16 − Compaction procedure (paving speed, paving width, number of passe s and number of rollers) − Joint formation y Faces of all cold upstanding edges to be painted y Air v oids not more than 2% above those in the main mat y Sealant applied to top surf ace of base and binder course joints : Bond coats - BS 594987 Tables 3 - 4 New 0.15kg/m2 Planed 0.6kg/m2 17 Clause 929 Dense Base and Binder Course Macadams (Design Mixtures) y y y y Simplified: Volumetric requirements in PD6691 Job mixture approval trial mix volumetrics - details given in BS 594987 Annex C Job mixture approval trial resistance to deformation – details given in BS594987 Annex D Stiffness requirement y Deformation resistance y − Smin 1500MPa − WTR to BS 598-110 until EN 13697:22 data available Clause 937 (SMA), 943 (Perf. HRA) and 952 (Deformation Resistance) • Clause 937 selects deformation requirements from PD 6691 Table D2 • Clause 943 selects deformation requirements from PD 6691 Table C3 • Clause 952 Deformation Resistance is no longer required (incorporated into relevant Clauses: 929, 930, 937 and 943) 18 Clause 942 Thin Surface Course Systems y y y (11/06) Surfacing Integrity - Performance Guarantee 14 The Contractor shall guarantee the integrity of the surfacing and the workmanship for a period of five years from the Contract completion date, or as otherwise specified in Appendix 7/1. NFG 24 (11/06) The guarantee periods should b e clearly stated as relating only to the surface course. An appropriate Special Requirement should b e included in the Conditions of Contract which draws particular attention to sub -Clauses 942.14. 942.15 and 942.16. At the end of the five-year guarantee period, the surfacing should be expected to b e in at least a “Moderate/Acceptab le” or a better condition after discounting any faults caused b y the sub strate, where the surface conditions are as defined in Appendix R of TRL Report 176. SHW Clause 942 BBA HAPAS Classes for texture depth Do not overspecify [1.3] High speed Medium speed Low speed <40mph 19 SHW Clause 921 Surface Macrotexture of Bituminous Surface Courses Clause 953 Durability of Bituminous Mixtures – Saturation Ageing Tensile Stiffness (SATS) Test y y y y Required for all binder course and base mixes Mi xture conditioned under pressure in a wet atmosphere Mi xture must have retained stiffness >80% Mi xtures containing 2% hydrated lime will be deemed to comply • Mainly a problem for all granite aggregate mixtures 20 Modern Surfacing We have to strive to keep up to date 21