Mixtures – How to Specify Them London Asphalt Specification 1

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