NZQA registered unit standard
Title
Design hot mix asphalt
Level
5
13514 version 4
Page 1 of 6
Credits
25
Purpose
People credited with this unit standard able to: identify hot mix
asphalt design objectives; select the aggregate and filler
blends; select the binder; identify, assess, control, and monitor
health and safety hazards and adverse effects on the
environment associated with hot mix asphalt design; prepare
test specimens and carry out test procedures to develop hot
mix asphalt designs; determine mix designs and prepare
reports; and determine plant settings to achieve a job mix
formula.
Classification
Pavement Surfacing > Asphalt Surfacing
Available grade
Achieved
Entry information
Critical health and
safety prerequisites
Unit 20455, Demonstrate basic knowledge of safety relating to
bituminous materials, or demonstrate equivalent knowledge
and skills.
Explanatory notes
1
The following legislation and requirements apply to this unit standard, and must be
complied with:
Health and Safety in Employment Act 1992;
Health and Safety in Employment Regulations 1995;
Resource Management Act 1991;
MS-2 Mix Design Methods, Asphalt Institute, available at
http://www.asphaltinstitute.org;
Site safety plan;
Contract specifications.
Any legislation or other requirements superseding any of the above will apply,
pending the review of this unit standard.
2
Personal protective equipment must be used throughout operations in accordance
with company procedures.
3
Assessment against this unit standard must be based on evidence from a workplace
context.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
13514 version 4
Page 2 of 6
4
Evidence is required of at least three mix designs.
5
Definitions
Company procedures refers to all documented policies, procedures and
methodologies of the candidate’s employer at the time of training including but not
limited to those relating to health, safety, environment, quality, and operations.
VFB means voids filled with binder.
VMA means voids in the mineral aggregate.
Outcomes and evidence requirements
Outcome 1
Identify hot mix asphalt design objectives.
Evidence requirements
1.1
Explicit design objectives are identified in accordance with specified contract
requirements.
1.2
Implicit design objectives are described in terms of workability, durability,
flexibility, fatigue resistance, skid resistance, permeability, and macro texture.
1.3
Design objectives are identified in terms of site and other constraints.
Range
constraints may include but are not limited to – pavement shape,
geometrics, topography, materials and equipment available, mix
type and layer thickness, clearances, live load limitations,
vibration.
Outcome 2
Select the aggregate and filler blends.
Evidence requirements
2.1
Source rock properties of available aggregates are evaluated for compliance
with contract specifications.
Range
2.2
includes but is not limited to – weathering resistance, crushing
resistance, polished stone value.
The influence of aggregate on final hot mix asphalt properties is evaluated.
Range
includes but is not limited to – particle size distribution, shape,
broken faces, sand equivalent, cleanness.
2.3
The use of fillers in terms of their function in open graded and dense graded
mixes are considered.
2.4
The economics of aggregate and filler supplies in terms of price, availability of
supply, and limitations of the asphalt production plant are considered.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
2.5
13514 version 4
Page 3 of 6
Specified particle size distribution limits are met.
Range
evidence is required of aggregate blend calculation.
Outcome 3
Select the binder.
Evidence requirements
3.1
The penetration grade of bitumen is considered in terms of site requirements.
3.2
The use of additives in asphalt mixes is considered and their function is
explained.
Range
3.3
includes but is not limited to – modifier, fibre, adhesion agent.
Binder is selected in accordance with contract specifications and job
requirements.
Outcome 4
Identify, assess, control, and monitor health and safety hazards and adverse effects on the
environment associated with hot mix asphalt design.
Evidence requirements
4.1
Health hazards are identified, assessed, and controlled in accordance with
company procedures and legislation.
4.2
Safety hazards are identified, assessed, and controlled in accordance with
manufacturer’s instructions, company procedures, and legislation.
4.3
Adverse effects on the environment are identified, assessed, and controlled in
accordance with company procedures and legislation.
Range
includes – adhesion agents, polymers, solvents.
4.4
Health and safety hazards are monitored in accordance with company
procedures and legislation.
4.5
Adverse effects on the environment are monitored in accordance with company
procedures and legislation.
Range
Infrastructure ITO
SSB Code 101813
includes – disposal of hazardous substances.
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
13514 version 4
Page 4 of 6
Outcome 5
Prepare test specimens and carry out test procedures to develop hot mix asphalt designs.
Evidence requirements
5.1
Requirements for, and status of, laboratory accreditation are confirmed in
accordance with client’s specifications.
5.2
Equipment calibration status, test methods, and documentation requirements
are identified in accordance with contract specifications.
5.3
Test equipment is described.
5.4
Batches of asphaltic concrete are mixed and test specimens are prepared in
accordance with specified test methods.
5.5
Volumetric properties of asphaltic concrete specimens are determined.
Range
5.6
bulk specific gravity, air voids, maximum theoretical specific
gravity, VMA, effective binder content;
may include but is not limited to – absorption, VFB, binder film
thickness, specified factors.
Mechanical properties of asphaltic concrete specimens are determined.
Range
stability, flow.
Outcome 6
Determine mix designs and prepare reports.
Evidence requirements
6.1
Test results are collated, graphed, and evaluated, and optimum binder content
is selected in accordance with contract requirements.
Range
includes but is not limited to – stability, flow, VFB, air voids, bulk
specific gravity, VMA, effective bitumen content.
6.2
Aggregate components and blend particle size distribution limits are established
in accordance with company procedures, and tolerance limits are applied to
aggregate supplier and asphalt production plant.
6.3
Job mix formulae are determined from the mix design and take account of plant
constraints.
6.4
Design reports nominating job mix formulae are prepared for approval in
accordance with contract specifications and company procedures.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
13514 version 4
Page 5 of 6
Outcome 7
Determine plant settings to achieve a job mix formula.
Evidence requirements
7.1
Aggregate blend requirements and tolerances are determined in accordance
with job mix formula.
Range
preblending of raw aggregates, cold feed aggregate blend ratio.
7.2
Plant settings are calculated in accordance with specific plant requirements.
7.3
Plant settings are reviewed and amended until production trials and testing
verify that job mix formula achieves design criteria and field trials verify that
design properties have been achieved.
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
24 March 1998
31 December 2013
Revision
2
5 January 1999
31 December 2013
Review
3
27 October 2005
31 December 2013
Review
4
15 March 2012
N/A
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.
Infrastructure ITO
SSB Code 101813
 New Zealand Qualifications Authority 2016
NZQA registered unit standard
13514 version 4
Page 6 of 6
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