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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
1The following requirements apply to this unit standard, and must be complied with:
Chipsealing in New Zealand, New Zealand Transport Agency, available at
MS-2Mix Design Methods, Asphalt Institute, available at
New Zealand Transport Agencyspecifications, available at
NZTA M1:Specification forRoading 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.
2Assessment against this unit standard may be based on evidence from workplace and/or provider contexts.
3Definition
VMArefers to voids in mineral aggregate.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of bituminous materials and additives.
Evidence requirements
1.1Bituminous materials used in asphalt mixes are described in terms of source and properties in accordance with Chipsealing in New Zealand and NZTA M1.
Rangeproperties – penetration, viscosity temperature relationship, flash point.
1.2Additives used in bituminous binders are described in terms of properties, effects on binder properties, and effects on asphalt mix properties.
Rangeincludes but is not limited to – diluents, antistripping agents, polymer modifiers, fibres.
Outcome 2
Demonstrate knowledge of aggregates and fillers used in asphalt paving mixes.
Rangeaggregates – fine, coarse.
Evidence requirements
2.1Aggregates are described in terms of origin and supply.
2.2Aggregates are described in terms of source properties.
Rangeincludes but is not limited to – weathering resistance, crushing resistance, polished stone value, water absorbency, bitumen absorbency.
2.3Aggregates are described in terms of processed properties.
Rangeincludes but is not limited to – particle size distribution, shape, broken faces, sand equivalent, cleanness.
2.4Fillers are described in terms of type and situations when they are required.
Rangemay include but is not limited to – fly ash, lime, silt.
Outcome 3
Demonstrate detailed knowledge of types of hot mix asphalt.
Evidence requirements
3.1Mix type and designation of dense asphaltic concrete are described in accordance with NZTA M10, NZTA P18P, and NZTA P23.
3.2Open-graded porous asphalt is described in accordance with NZTA P11.
Outcome 4
Demonstrate detailed knowledge of the uses of types of hot mix asphalt.
Rangedense-graded, open-graded porous, stone mastic.
Evidence requirements
4.1Hot mix asphalt types are described in terms of use in structural pavements.
4.2Hot mix asphalt is described in terms of use in surfacing courses.
Rangewearing 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
5.1Mechanical and volumetric properties of asphalt mixes are described in accordance with the Marshall method of mix design.
Rangestability, flow, air voids, VMA.
5.2Properties are described in terms of effective binder content.
5.3Asphalt mixes are described in terms of factors influencing durability.
Rangevoids, binder film thickness, aggregate type.
5.4Asphalt mixes are described in terms of workability.
Rangebinder type, binder content, aggregate shape, broken faces, particle size distribution, stability flow ratio.
5.5Properties are described in terms of sensitivity to deviations from design mix formulae.
5.6Properties are described in terms of sensitivity of mix to ineffective compaction.
Outcome 6
Demonstrate detailed knowledge of the selection of asphalt mixes.
Evidence requirements
6.1Selection of asphalt mixes is described in terms of need for pretreatment for existing pavement conditions.
Rangeincludes but is not limited to – texture, permeability, flushing, cracking, rutting, potholes, deflection, pavement shape.
6.2Selection of asphalt mixes is described in terms of pavement use.
Rangedriveway, footpath, sports surface, road, motorway, airport runway, airport taxiway, container terminal, heavy industrial site.
6.3Selection of asphalt mixes is described in terms of pavement stress.
Rangeincludes but is not limited to – traffic types, traffic volume, traffic mix, traffic speed, static loads.
6.4Selection of asphalt mixes is described in terms of site constraints.
Rangeincludes 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.
6.5Selection of asphalt mixes is described in terms of client’s requirements.
Rangerequirements include but are not limited to – texture, skid resistance, noise minimisation, water spray reduction, shape, and layer thickness.
6.6Selection of asphalt mixes is described in terms of performance requirements of NZTA P18P and NZTA P23.
Planned review date / 31 December 2016Status information and last date for assessment for superseded versions
Process / Version / Date / Last Date for AssessmentRegistration / 1 / 27 October 2005 / 31 December 2013
Review / 2 / 15 March 2012 / N/A
Consent and Moderation Requirements (CMR) reference / 0101
This CMR can be accessed at
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 if you wish to suggest changes to the content of this unit standard.
Infrastructure ITOSSB Code 101813 / New Zealand Qualifications Authority 2018