NZQA registered unit standard version 1 Page 1 of 5. Demonstrate knowledge of equipment and processes for constructing slurry surfacings

Transcription

1 Page 1 of 5 Title Demonstrate knowledge of equipment and processes for constructing slurry surfacings Level 4 Credits 6 Purpose People credited with this unit standard are able to demonstrate knowledge of: equipment used; pre-construction processes; construction processes; and post-construction processes for slurry surfacings. Classification Infrastructure Works > Bitumen Surfacing Construction Available grade Achieved Explanatory notes 1 Competence in this unit standard requires knowledge of the current editions of the following references: RNZ 9806, Specification for Slurry Surfacings RNZ 9806: June 2010, Roading New Zealand, available at ISSA A105 Recommended Performance Guideline for Emulsified Asphalt Slurry Seal A105 (Revised February 2010) International Slurry Surfacing Association available at ISSA A143 Recommended Performance Guideline For Micro Surfacing A143 (Revised February 2010), International Slurry Surfacing Association available at 2 Assessment against this unit standard must be based on evidence from a workplace context. 3 Evidence is required from working on three contracts covering each of slurry, cape seal, rut filling. 4 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. Maintenance period means the period of time from the removal of temporary speed restrictions until final acceptance by the engineer, during which time the contractor may have corrective action obligations specified in the contract specifications. Operating manuals refers to the plant operating manual and manuals written for specific components or items of plant and equipment that may be published by the manufacturer or the company. Protection period means the period of time from the completion of construction until the removal of temporary speed restrictions, during which time the contractor may have corrective action obligations specified in the contract specifications.

2 Page 2 of 5 Slurry surfacing is the generic term for a mix of asphalt emulsion binder, crushed aggregate, and stabilising filler. A development of slurry using a polymer modified binder and selected aggregates is known as micro surfacing. Outcomes and evidence requirements Outcome 1 Demonstrate knowledge of equipment used for constructing slurry surfacings. 1.1 Slurry machine is described in terms of its components and functions. components mixing box, weigh feeders, volumetric feeders, flow meters, fibre dispenser, storage hopper, emulsion tank, dope tank, control system, secondary strike off, rut box, crane, pump augers; functions loading, proportioning, mixing, spreading, screeding. 1.2 Slurry machine is described in terms of effects of machine faults on the quality of the surfacing. faults blocked filters, incorrect calibration of feeders, emulsion flows, addition of water, poor mixing, runs into channel too thin; 1.3 The limitations and alternatives to slurry machines are identified. limitations size, weight, width; alternatives smaller machine, chute and wheelbarrow, concrete mixer. 1.4 Other slurry surfacing equipment is described in terms of when it is needed. where tack needed, where sprayer needed, where rolling needed, type of roller needed. Outcome 2 Demonstrate knowledge of pre-construction processes for slurry surfacings. 2.1 Checks to be made prior to accepting a site for laying bituminous mixes are explained in terms of meeting contract requirements. checks pre-seal repairs completed, site suitable for surfacing, site extent marked out; examples of checks are given from two different sites. 2.2 Pre-construction processes are described in terms of general site preparation requirements for slurry surfacings.

3 Page 3 of 5 programming pavement repairs, hazard identification and control, environmental protection, temporary traffic management, loading sites, stockpile site, parking and unloading areas, ends and widths marked out, location on road marked. 2.3 Pre-construction processes are described in terms of complying with site specific instructions. site safety, public safety, pavement shape, geometric constraints, live load limitations, access, obstructions, radio, drop off area, location of ancillary services, climate. 2.4 Pre-construction processes for slurry surfacing are described in terms of pretreatment types and factors to take into account when determining pretreatment requirements. pre-treatment types cleaning, sweeping, pre-levelling, tack coat; membrane seal; factors pavement condition, treatment type, site constraints, resources. 2.5 Pre-construction processes are described in terms of determining and confirming plant, equipment, and labour resources for slurry surfacing. tack coat applicator, sprayer, slurry machine, loader, roller. 2.6 Pre-construction processes for slurry surfacing are described in terms of scheduling sampling and testing to meet contract requirements. testing mix design, aggregate, emulsion, slurry, aggregate grading, sand equivalent, aggregate moisture content, binder content, slurry gradation, cement, additives, dope. 2.7 Pre-construction processes are described in terms of identifying and notifying affected parties. identify at least four affected parties and any four methods of notification. 2.8 Pre-construction processes are described in terms of identifying, recording, and protecting service overs, road furniture, and adjacent surfaces. Outcome 3 Demonstrate knowledge of construction processes for slurry surfacings. 3.1 Transport of slurry surfacing plant, equipment, and materials to laying site is explained in terms of logistics.

4 Page 4 of 5 aggregate stockpiles, emulsion trailer, emulsion tanker, slurry machine, roller, loader. 3.2 Surface preparation is explained in terms of cleaning and masking requirements and methods. 3.3 Surface preparation is described in terms of tack coat and membrane seal timing, types, and methods. 3.4 Slurry surfacing is described in terms of construction processes, checks, and adjustments. processes mixing, starts and stops, butting, lapping, tapering, managing product viscosity, managing screed, control of break and cure with dope; checks emulsion quality, aggregate quality, contamination, moisture content of aggregate, stockpile cover, excessive cement; adjustments feeder rates, truck speed, feed to high side, auger speeds. 3.5 Slurry surfacing construction is described in terms of when hand work is required and hand work methods. 3.6 Site safety and traffic management are explained in terms of site requirements, lane closures, and adjustments required during slurry surfacing construction. Outcome 4 Demonstrate knowledge of post-construction processes for slurry surfacings. 4.1 Slurry site clean-up processes are explained in accordance with company procedures. roadmarking, removing start finish paper, removing service protection, waste disposal. 4.2 Protection of a road surface during the protection period is described in accordance with company procedures. timing, traffic loads, traffic speed, positive traffic control. 4.3 Monitoring the newly laid surfacing for the maintenance period is described and corrective actions are explained in accordance with company procedures. monitoring for aesthetics, texture, abrasion loss, skid resistance, deformation, unravelling, flushing.

5 Page 5 of 5 Planned review date 31 December 2019 Status information and last date for assessment for superseded versions Process Version Date Last Date for Assessment Registration 1 19 February 2015 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 (CMRs). 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 the qualifications@infrastructureito.org.nz if you wish to suggest changes to the content of this unit standard.