NZQA registered unit standard
21665 version 2
Page 1 of 5
Title
Demonstrate knowledge of materials and mixes for hot mix asphalt
designs
Level
5
Credits
10
Purpose
People credited with this unit standard are able to: demonstrate
knowledge of bituminous materials, additives, aggregates, and
fillers used in asphalt paving mixes; and demonstrate detailed
knowledge of the types and uses of hot mix asphalt, and the
properties and selection of asphalt mixes.
Classification
Pavement Surfacing > Asphalt Surfacing
Available grade
Achieved
Explanatory notes
1
The following requirements apply to this unit standard, and must be complied with:
Chipsealing in New Zealand, New Zealand Transport Agency, available at
http://www.nzta.govt.nz/resources/chipsealing-new-zealand-manual/;
MS-2 Mix Design Methods, Asphalt Institute, available at
http://www.asphaltinstitute.org/store_category_browse.asp?ic_id=11;
New Zealand Transport Agency specifications, available at
http://www.nzta.govt.nz/resources/:
NZTA M1: Specification for Roading Bitumens;
NZTA M10: Specification for Asphaltic Concrete;
NZTA M10 Notes: Notes to the Specification for Asphaltic Concrete;
NZTA P11: Specification for Open Graded Porous Asphalt;
NZTA P11 Notes: Notes to the Specification for Open Graded Porous Asphalt;
Where specified in the contract documents, the following pilot specifications, or
confirmation of their currency, are available by contacting the Operations Manager,
New Zealand Transport Agency National Office, Telephone 04 894 6316 –
NZTA P18P: Pilot Performance Based Specification for Hot Mix Asphalt;
NZTA P23: Performance Based Specification for Hotmix Asphalt Wearing Course
Surfacing.
Any requirements superseding any of the above will apply, pending the review of this
unit standard.
2
Assessment against this unit standard may be based on evidence from workplace
and/or provider contexts.
3
Definition
VMA refers to voids in mineral aggregate.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
21665 version 2
Page 2 of 5
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of bituminous materials and additives.
Evidence requirements
1.1
Bituminous materials used in asphalt mixes are described in terms of source
and properties in accordance with Chipsealing in New Zealand and NZTA M1.
Range
1.2
properties – penetration, viscosity temperature relationship, flash
point.
Additives used in bituminous binders are described in terms of properties,
effects on binder properties, and effects on asphalt mix properties.
Range
includes but is not limited to – diluents, antistripping agents,
polymer modifiers, fibres.
Outcome 2
Demonstrate knowledge of aggregates and fillers used in asphalt paving mixes.
Range
aggregates – fine, coarse.
Evidence requirements
2.1
Aggregates are described in terms of origin and supply.
2.2
Aggregates are described in terms of source properties.
Range
2.3
Aggregates are described in terms of processed properties.
Range
2.4
includes but is not limited to – weathering resistance, crushing
resistance, polished stone value, water absorbency, bitumen
absorbency.
includes but is not limited to – particle size distribution, shape,
broken faces, sand equivalent, cleanness.
Fillers are described in terms of type and situations when they are required.
Range
Infrastructure ITO
SSB Code 101813
may include but is not limited to – fly ash, lime, silt.
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
21665 version 2
Page 3 of 5
Outcome 3
Demonstrate detailed knowledge of types of hot mix asphalt.
Evidence requirements
3.1
Mix type and designation of dense asphaltic concrete are described in
accordance with NZTA M10, NZTA P18P, and NZTA P23.
3.2
Open-graded porous asphalt is described in accordance with NZTA P11.
Outcome 4
Demonstrate detailed knowledge of the uses of types of hot mix asphalt.
Range
dense-graded, open-graded porous, stone mastic.
Evidence requirements
4.1
Hot mix asphalt types are described in terms of use in structural pavements.
4.2
Hot mix asphalt is described in terms of use in surfacing courses.
Range
wearing courses, structural layers, maintenance patching,
driveway, footpath, surface levelling, sports surface, road,
motorway, airport runway, airport taxiway, container terminal,
heavy industrial site.
Outcome 5
Demonstrate detailed knowledge of properties of asphalt mixes.
Evidence requirements
5.1
Mechanical and volumetric properties of asphalt mixes are described in
accordance with the Marshall method of mix design.
Range
stability, flow, air voids, VMA.
5.2
Properties are described in terms of effective binder content.
5.3
Asphalt mixes are described in terms of factors influencing durability.
Range
5.4
Asphalt mixes are described in terms of workability.
Range
5.5
voids, binder film thickness, aggregate type.
binder type, binder content, aggregate shape, broken faces,
particle size distribution, stability flow ratio.
Properties are described in terms of sensitivity to deviations from design mix
formulae.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
5.6
21665 version 2
Page 4 of 5
Properties are described in terms of sensitivity of mix to ineffective compaction.
Outcome 6
Demonstrate detailed knowledge of the selection of asphalt mixes.
Evidence requirements
6.1
Selection of asphalt mixes is described in terms of need for pretreatment for
existing pavement conditions.
includes but is not limited to – texture, permeability, flushing,
cracking, rutting, potholes, deflection, pavement shape.
Range
6.2
Selection of asphalt mixes is described in terms of pavement use.
Range
6.3
driveway, footpath, sports surface, road, motorway, airport
runway, airport taxiway, container terminal, heavy industrial site.
Selection of asphalt mixes is described in terms of pavement stress.
includes but is not limited to – traffic types, traffic volume, traffic
mix, traffic speed, static loads.
Range
6.4
Selection of asphalt mixes is described in terms of site constraints.
includes but is not limited to – climate, pavement shape, geometric
constraints, materials available, equipment available, layer
thickness, clearances, load limitations (dead and live), vibration,
limitations on use of compaction equipment.
Range
6.5
Selection of asphalt mixes is described in terms of client’s requirements.
requirements include but are not limited to – texture, skid
resistance, noise minimisation, water spray reduction, shape, and
layer thickness.
Range
6.6
Selection of asphalt mixes is described in terms of performance requirements of
NZTA P18P and NZTA P23.
Planned review date
31 December 2016
Status information and last date for assessment for superseded versions
Process
Version Date
Last Date for Assessment
Registration
1
27 October 2005
31 December 2013
Review
2
15 March 2012
N/A
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
21665 version 2
Page 5 of 5
Consent and Moderation Requirements (CMR) reference
0101
This CMR can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Please note
Providers must be granted consent to assess against standards (accredited) by NZQA,
before they can report credits from assessment against unit standards or deliver courses
of study leading to that assessment.
Industry Training Organisations must be granted consent to assess against standards by
NZQA before they can register credits from assessment against unit standards.
Providers and Industry Training Organisations, which have been granted consent and
which are assessing against unit standards must engage with the moderation system that
applies to those standards.
Requirements for consent to assess and an outline of the moderation system that applies
to this standard are outlined in the Consent and Moderation Requirements (CMR). The
CMR also includes useful information about special requirements for organisations wishing
to develop education and training programmes, such as minimum qualifications for tutors
and assessors, and special resource requirements.
Comments on this unit standard
Please contact Infrastructure ITO askus@infratrain.co.nz if you wish to suggest changes to
the content of this unit standard.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016