Specification for asphaltic concrete TNZ M/10 - NZ Transport Agency

TNZ M/10: 2005
SPECIFICATION FOR ASPHALTIC CONCRETE
1. SCOPE
This specification describes the required physical properties of dense graded asphaltic
concrete for use in road pavements. Component physical characteristics are specified,
as are the requirements of the asphaltic concrete mixture.
Other innovative asphalt mixes including or otherwise the inclusion of crushed glass,
higher percentages of RAP and other waste or industrial by-products that are not
acceptable under this specification can be submitted to Transit New Zealand’s
Engineering Policy Manager for consideration of approval for use (see TNZ M/10:
2005 Notes).
2. RELATED DOCUMENTS
The following Related Documents are referenced in the text of this specification. In
all cases the most recent version of each document must be used.
2.1 TNZ M/1 Specification for Roading Bitumens
2.2 Asphalt Institute Mix Design Methods for Asphalt Concrete and other Hot-
Mix Types (MS-2)
2.3 Standards New Zealand NZS 4407 Methods of Sampling and Testing Road
Aggregates
2.4 ASTM C117 Standard Test Method for Materials Finer than 75-mm Sieve in
Mineral Aggregates by Washing
2.5 ASTM C127 Standard Test Method for Specific Gravity and Absorption of
Coarse Aggregate
2.6 ASTM C128 Standard Test Method for Specific Gravity and Absorption of
Fine Aggregate
2.7 ASTM C136 Standard Test Method for Sieve Analysis of Fine and Coarse
Aggregates
2.8 ASTM D979 Standard Practice for Sampling Bituminous Paving Mixtures
2.9 ASTM D1559 Resistance to Plastic Flow of Bituminous Mixtures Using the
Marshall Apparatus
2.10 ASTM D2041 Theoretical Maximum Specific Gravity and Density of
Bituminous Paving Mixtures
2.11 ASTM D2172 Quantitative Extraction of Bitumen From Bituminous Paving
Mixtures
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2.12 ASTM D2726 Bulk Specific Gravity and Density of Compacted Bituminous
Mixtures using Saturated Surface Dry Specimens
2.13 ASTM D3203 Percent Air Voids in Compacted Dense and Open Bituminous
Paving Mixtures Roading New Zealand publication BCA 9805. Quality
Assurance of Aggregates for Chipseals and Bituminous Mixes
3. DEFINITIONS
3.1 Asphaltic Concrete
Asphaltic Concrete (“hot-mix asphalt”) is a dense, continuously graded mixture of
coarse and fine aggregates, mineral filler and bitumen produced hot in a mixing plant.
It is delivered, spread and compacted while hot.
3.2 Coarse Aggregate
The Coarse Aggregate is the fraction of the aggregate components retained on a
4.75mm test sieve.
3.3 Fine Aggregate
Fine aggregate is the fraction of the aggregate components passing the 4.75mm test
sieve, excluding mineral fillers.
3.4 Mineral Filler
Mineral Filler is finely ground particles of limestone, hydrated lime, Portland cement
or other non-plastic mineral matter, predominantly finer than 0.075mm that is added
to the mix.
3.5 Binder
Unless specified in the specific contract requirements, binder is penetration grade
bitumen complying with TNZ M/1 specification.
3.6 Specified Mix Envelope
The Specified Mix Envelope (SME) is the asphaltic concrete particle size distribution
and effective bitumen content limits as set out in Section 5.
3.7 Job Mix Formula
The Job Mix Formula (JMF) is the combined aggregate particle size distribution and
total bitumen content that falls within the SME and produces a mix that complies with
the volumetric and mechanical criteria specified in Section 5.
3.8 Voids in the Mineral Aggregate
The Voids in the Mineral Aggregate (VMA) is the volume of intergranular void space
between the aggregate particles of a compacted mixture that includes the air voids and
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the effective bitumen content, expressed as a percentage of the total volume of the
sample (see related document 2.2).
3.9 Base Mix
A mix used in structural pavement layers beneath the final wearing mix.
3.10 Wearing Mix
A mix applied as the uppermost layer in a pavement subjected to the wearing action
of traffic.
3.11 Reclaimed Asphalt Pavement (RAP)
Reclaimed asphalt Pavement (RAP) is material comprising old asphalt that has been
processed by crushing and/or screening to produce a free flowing and consistent
product.
3.12 Maximum size
The maximum size of a mix is the sieve size at which 100% of the aggregate passes
4. MATERIALS
4.1 Testing
All sampling and laboratory testing required to demonstrate that materials used, and
the resulting mix comply with this specification shall be performed by a laboratory
accredited to ISO 17025 (eg. IANZ Accreditation). Testing frequency of aggregate
and binder shall be in accordance with the guidelines given in the Roading New
Zealand publication BCA 9805.
4.2 Coarse Aggregate
Coarse aggregate shall consist of crushed stone or crushed gravel or a combination of
the two, produced from hard durable rock or river boulders unless otherwise approved
by Transit New Zealand (Transit). The source material from which individual
components are produced shall comply with the Crushing Resistance and Weathering
Resistance of Table 4.1 and the blended coarse aggregate shall comply with the
Broken Faces requirements:
Table 4.1: Requirements for Coarse Aggregate
CRITERIA TEST METHOD REQUIREMENTS
Crushing Resistance NZS 4407 Test 3.10 200 kN minimum
Weathering Resistance NZS 4407 Test 3.11 AA or BA
Single Broken Faces NZS 4407 Test 3.14 98% minimum
Two Broken Faces NZS 4407 Test 3.14 60% minimum
Polished Stone Value BS 812 *see below
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• refer to specific contract requirements for minimum Polished Stone Value. At
least 85% by mass of the coarse aggregate shall comply with the minimum
Polished Stone Value specified by the contract document
4.3 Fine Aggregate
Fine aggregate shall consist of particles of sand, crushed stone or crushed gravel or a
mixture of these materials unless otherwise approved by Transit. The source material
from which any crushed fine aggregate is produced shall comply with the crushing
resistance criteria of Table 4.2:
Table 4.2: Requirements for Fine Aggregate
CRITERIA TEST METHOD REQUIREMENTS
Crushing Resistance NZS 4407 Test 3.10 200 kN minimum
Sand Equivalent, or NZS 4407 Test 3.6 35 minimum, or
Clay Index ( 90
0.075 > 65
The bitumen used in the asphaltic concrete mixture shall be B80 or B60 (i.e.
80/100 or 60/70) penetration grade compliant with TNZ M/1 Specification. The
required grade (or alternative binder materials) will be specified by specific
contract requirements.
4.6 RAP
RAP may be recycled by adding it as an ingredient during the mixing process
while manufacturing new asphaltic concrete. Up to 15 % RAP by mass can be
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added. The Transit New Zealand Engineering Policy Manager can approve mix
designs using higher percentages of RAP (see Notes).
RAP shall be of appropriate quality to ensure that the final product shall comply
in all respects with the requirements of Section 5 of this specification.
RAP shall be further processed by crushing and/or screening to a maximum size
not exceeding the maximum size of the asphaltic concrete to be produced and to
ensure a reasonably free flowing, and consistent product.
5. MIX DESIGN
RAP shall be stored in separate stockpiles prior to use
Laboratory mix design shall be carried out in accordance with the Asphalt Institute
Mix Design Methods for Asphaltic Concrete (related document 2.2)
The particle size distribution of the Job Mix Formula (JMF) shall comply with the
Specified Mix Envelopes of Table 5.1 (Asphaltic Concrete) or Table 5.2 (Thin
Surfacing Mix) unless the volumetric and mechanical properties of Tables 5.1 and 5.2
cannot be achieved. In this instance, the JMF may deviate outside the SME (see
definition 3.7).
Mixes shall comply with the effective binder content and VMA requirements of
Tables 5.1 or 5.2 and the volumetric and mechanical properties of Table 5.3.
Test specimens shall be made using the method of ASTM D1559 or equivalent except
that mechanical compaction may be used. The specimens shall be compacted using
75 compaction blows on each side of the specimen.
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Table 5.1: Asphaltic Concrete Specified Mix Envelopes
MIX
MIX 40 MIX 25 MIX 20 MIX 15 MIX 10
DESIGNATION
Type of Mix Base Base or
Wearing
Base or
Wearing
Wearing Levelling or
Wearing
Layer Thickness 75 - 150 65 - 100 50 - 80 40 - 65 25 - 40
Range (mm)
Sieve Size
Percentage Passing Sieve
(mm) Mix 40 Mix 25 Mix 20 Mix 15 Mix 10
37.5 100 - - - -
26.5 84 - 95 100 - - -
19.0 70 - 90 86 - 95 100 - -
16.0 - - - 100 -
13.2 62 - 82 73 - 86 83 - 95 - -
9.5 55 - 75 63 - 78 70 - 90 79 - 95 100
6.7 48 -– 67 54 -– 69 60 -– 79 69 -– 84 80 - 95
4.75 43 - 60 46 - 61 52 - 70 58 - 75 70 - 85
2.36 32 - 47 34 - 49 40 - 55 43 - 61 55 - 75
1.18 23 - 37 25 - 38 29 - 43 32 - 48 40 - 60
0.600 16 - 28 18 - 28 20 - 32 21 - 36 27 - 47
0.300 10 - 20 13 - 21 13 - 23 15 - 26 18 - 33
0.150 6 - 14 7 - 15 8 - 16 10 - 17 12 - 22
0.075 3 - 8 3 - 9 4 - 10 5 - 11 6 - 12
Effective Binder 3.5 - 5.0 3.8 - 6.0 4.0 - 6.0 4.5 - 6.0 5.0 - 7.0
Content (%)
Minimum VMA 11 12 13 14 15
(%)
Note: The minimum VMA requirement is an addition to the Specification and may
require review. Flexibility is required until sufficient data is available to
confirm these limits.
The JMF particle size distribution may need to deviate outside the limits in the above
table to achieve the required volumetric and mechanical properties of the mix. This is
acceptable.
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The effective binder contents given are based on an aggregate bulk dry specific
gravity of 2.65. Where the aggregate has a specific gravity greater than 2.70 then the
effective binder contents may be adjusted by the following factor:
2.65
aggregate bulk dry specific gravity
Table 5.2: Thin Surfacing Mix Specified Mix Envelope
MIX DESIGNATION
MIX 10 TS
Type of Mix
Levelling or Wearing
Layer Thickness (mm) 25 - 40
Sieve Size (mm)
Percentage Passing Sieve
9.5 100
6.7 80 - 95
4.75 60 - 80
2.36 40 - 60
1.18 26 - 45
0.600 18 - 32
0.300 11 - 23
0.150 7 - 15
0.075 4 - 8
Effective Binder Content (%) 5.0 - 6.5
Minimum VMA (%) 15
Table 5.3: Laboratory Mix Design Volumetric and Mechanical Requirements
CRITERIA MIXTURE TYPE REQUIREMENTS
Stability (kN) Base 5.35 minimum
Wearing 6.65 minimum
Air Voids (%) Base 2.0 - 3.0
Wearing 3.0 - 4.0
Flow (mm) Base 2.0 - 4.0
Wearing 2.0 - 4.5
For the design of Mix 40 the following technique shall be used
The aggregate fraction passing the 37.5 mm sieve but retained on the 26.5 mm
sieve will be removed and replaced by an equivalent amount of the aggregate
fraction passing the 26.5 mm sieve but retained on the 19.0 mm sieve.
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6. PRODUCTION
The manufacturing plant shall be calibrated and operated to consistently produce a
uniform mixture within the tolerances specified by Table 7.1.
If RAP is to be added then the manufacturing process shall provide for the addition of
RAP to the mixer separately from other mix components by a method that avoids
damage to the RAP by overheating. For drum plants a recycling ring entry or similar,
that introduces RAP outside the area of direct contact with the flame is essential.
If mix is to be stored prior to transportation and laying, storage bins shall be designed
and controlled to prevent segregation and minimise degradation of the mix.
Aggregates shall be stored at the plant in a manner such that each separate aggregate
component and stockpile is physically separate. Conditions of storage shall be
arranged so that the aggregate stockpiles are not contaminated, nor subject to
deterioration.
The binder shall be heated at the plant to a temperature at which it can be properly
handled by the pumping system. Any binder heated above 175° C, or held for more
than 8 hours above 162° C shall be rejected and not used unless subsequent testing
shows compliance with M/1 specification. The maximum temperatures for some
modified or alternative binders may exceed the above limits, subject to agreement
with the Engineer.
The production temperature of the mix shall not exceed 170° C unless cartage and
placement conditions require otherwise. Production temperatures higher than 170° C
are subject to agreement with the Engineer.
Mixing shall be carried out so that at least 95% of the coarse aggregate particles are
fully covered with bitumen. When required, aggregate coating may be determined
using the method of ASTM D2489.
The mixture may be stored in an insulated storage bin for up to 8 hours before
delivery to the site as long as the delivered temperature of the mix to the site can
meets the delivery temperature designated by the contractor and agreed by the
Engineer. If mix is stored for longer periods then the Contractor must demonstrate
that the period of extended storage has no effect on the properties of the mix.
7 TESTING
Samples of the Asphaltic Concrete Mixture shall be drawn from production batches
and tested. Samples shall be taken in accordance with ASTM D979 or equivalent,
and obtained from the mixing plant.
The samples shall be tested for total bitumen content and particle size distribution.
Test results shall fall within the mix control envelope, formed by applying the
tolerances of Table 7.1 to the JMF particle size distribution.
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Total bitumen content shall be measured using the method of ASTM D2172 or
approved alternative. Suitable alternatives include the solvent extraction method
generally designated ADL 4.02/15a, Ignition using a furnace (ASTM D6307) and
Nuclear methods. Note that if Ignition or Nuclear methods are used, appropriate
calibration offsets must be established.
Unless otherwise specified, the testing frequency shall be one sample per 200 tonnes
or a maximum of three samples per production lot.
Acceptance of the mix will be based on lots. A production lot will normally consist of
a days or a shift production or as detailed in the Contractor’s Quality Plan. When a
day's output is less than 100 tonnes and the same asphaltic concrete mix is to be
produced on subsequent days for the same pavement section, the lot considered for
acceptance will include the next day's production.
Table 7.1: Mix Control Envelope Tolerances
CRITERIA
PERMISSIBLE VARIATION FROM JMF
(% BY MASS OF TOTAL MIXTURE)
Individual Results Average of Three
Tests/lot
Aggregate coarser than 0.600 mm ± 8.0 ± 5.0
Aggregate passing 0.600 and 0.300 mm ± 6.0 ± 4.0
sieves
Aggregate passing 0.150 mm and finer ± 3.0 ± 2.0
Total Bitumen: Mix 10, Mix 15, Mix ± 0.5 ± 0.3
20, TS 10
Bitumen: Mix 25, Mix 40 ± 0.6 ± 0.4
.
Note the particle size distribution acceptance limits derived from application of the
permissible variations of Table 8.1 to the JMF particle size distribution may allow test results
to fall outside the SME envelopes of Table 5.1 or 5.2.
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