Introducing the Western Queensland Best Practice Guidelines IPWEAQ Southern Roads Symposium 30 May 2018, Toowoomba Mike Pickering, Director (Pavements, Research and Innovation), Queensland Transport and Main Roads 1 |
About us 2 | Type footer details here | 6 June 2018
Purpose and outline • High level overview of suite • Briefly discuss: background each guideline. 3 | 3 | Introducing the WQBPGs | 30 May 2018
Initial release in 2000 4 | 4 | Introducing the WQBPGs | 30 May 2018
Current publications • WQ30 Climate of western Queensland • WQ31 Geology and geomorphology of western Queensland • WQ32 Soils of western Queensland • WQ33 Materials sources in western Queensland • WQ35 Paving materials and type cross sections for roads on expansive soils in western Queensland* • WQ37 Drainage structures on expansive soils in western Queensland • WQ43 Erosion control in western Queensland • WQ51 Site rehabilitation and restoration *Ross Guppy will present on this next. 5 | 5 | Introducing the WQBPGs | 30 May 2018
Purpose • Reduce risk • Capitalise on past experience and knowledge: consistency fit for purpose pavement material selection and extraction pavement and drainage structure design pavement and drainage structure construction maintenance. 6 | 6 | Introducing the WQBPGs | 30 May 2018
Limitations • Guideline not prescriptive expertise/trials required • For TMR’s North West, Central West and South West districts • Empirical based on historic traffic and climate conditions. 7 | 7 | Introducing the WQBPGs | 30 May 2018
Relies on Low average rainfall Assumes Short rainfall durations Keeping the water out No moisture within 5m e.g. floodways, for extended periods perched water tables Pavement material properties Pavement type cross section Priority to keep water out: Extent and type of surfacing Longitudinal drainage solutions 8 | 8 | Introducing the WQBPGs | 30 May 2018
Relies on • Optimised use of local materials local experience research trials observed long term performance. 9 | 9 | Introducing the WQBPGs | 30 May 2018
Relies on • Recorded local experience past investment in research and trials validation through in-service performance Roads Performance Study in the 1980s and 1990s. Districts 4, 7, 8 &10 Major Roads Non-exp Subgrades Comparison between Districts (all seal widths) 100% Percentage within 90% each District District 80% 4 70% 60% District 15A 14E 14D 14B 50% 13H 14C 8 40% 13G 30% Districts 13F 20% 7 & 10 13D 13C 10% 13B 0% 13A 23C 18E 18D Very Good Good Adequate Poor 23B Rutting Performance Category 10 | 10 | Introducing the WQBPGs | 30 May 2018
Relies on • Lower traffic impacts relatively low traffic volumes and axle loads Configurations current at the time of research empirical. 11 | 11 | Introducing the WQBPGs | 30 May 2018
Relies on • Geological knowledge limited hard rock sources knowing the geology of available non-standard material(s). 12 | 12 | Introducing the WQBPGs | 30 May 2018
This means Then consider If standard non-standard materials are materials which Don’t comply with Unavailable locally MRTS05 Types 1 to 3 Too costly to transport Are naturally-occurring aggregates and soil Are extracted and processed using low- effort and low-cost means 13 | 13 | Introducing the WQBPGs | 30 May 2018
WQ30 Climate of western Queensland • Key parameters: rainfall Southern Oscillation Index (contributes to rainfall) temperature solar radiation / UV wind Thornthwaite index evaporation extreme events. 14 | 14 | Introducing the WQBPGs | 30 May 2018
WQ30 and rainfall Rainfall typically low, unreliable and unpredictable • Mean annual rainfall not a good measure of rainfall in any particular year • For example, analysis of 110 years of rainfall data for Winton indicated that: 45% of years had <80% of mean annual rainfall 28% of years had 80% to 120% of mean Bureau of Meteorology State of the Climate annual rainfall 2016 reports rainfall trend over past 20 years. 27% of the years had >120% of mean annual rainfall. 15 | 15 | Introducing the WQBPGs | 30 May 2018
Bureau of Meteorology longer-term trends in rainfall 16 | 16 | Introducing the WQBPGs | 30 May 2018
Temperature • Mean summer maxima typically 36 0 C to 40 0 C • Summer minima typically 21 0 C to 24 0 C • BOM State of the Climate 2016 reports its getting warmer. 17 | 17 | Introducing the WQBPGs | 30 May 2018
WQ31 Geology and geomorphology of western Queensland Sections: • geological structure • stratigraphy • geological history post-Jurassic • geomorphology • materials. 18 | 18 | Introducing the WQBPGs | 30 May 2018
WQ31 • 13 types of material sources described. • Described in geological terms and age of formation. • Tabulation of materials in terms of their geological and geomorphological expression. 19 | 19 | Introducing the WQBPGs | 30 May 2018
WQ31 20 | 20 | Introducing the WQBPGs | 30 May 2018
WQ32 Soils of western Queensland • Useful for classifying materials • Covers: mapping definitions soil classification soil distribution soil descriptions c racking clays (‘black soils’, ‘grey brown and red clays’) earths lithosols sandy soils desert loams. 21 | 21 | Introducing the WQBPGs | 30 May 2018
WQ33 Materials sources in western Queensland • Describes how formed, likely occurrence and characteristics • Typically specified as ‘Type 4’ material in MRTS05 • Covers: materials standards source assessment classification of sources ancient rocks tertiary basalt sandstone. 22 | 22 | Introducing the WQBPGs | 30 May 2018
13 materials described in WQ33 23 | 23 | Introducing the WQBPGs | 30 May 2018
Technical note 140 TN140 Source Material Assessment for Subtype 2.5, Subtype 3.5 and Type 4 Unbound Pavement • A best practice guide for source assessment • Assures the quality and supply capacity of source/source material. 24 | 24 | Introducing the WQBPGs | 30 May 2018
Transport and Main Roads’ Pavement Design Supplement “In drier parts of Queensland where traffic volumes are low, marginal or non-standard materials (also typically referred to as Type 4 materials) have been used extensively and many have performed satisfactorily. Use of such materials typically requires project- specific technical specifications be developed. These technical specifications should be based on local experience with the particular material, including its construction and handling requirements, historic performance and future performance expectations for the project. The use of laboratory methods, such as the repeated load triaxial test, may assist in predicting the likely performance of these materials over a range of moisture conditions relative to standard materials .” 25 | 25 | Introducing the WQBPGs | 30 May 2018
WQ33 Example ‘sandstone’ • Found within the outcrop area of a number of geological units of Rolling Downs Group (RDG) of Cretaceous age. • Most common in Winton, Mackunda and Wallumbilla Formations. • Typically occurs as a series of gently dipping beds, sub- cropping under a 1m to 2m thick layer of black soil. • Thickness of units generally exceed ≤ 3m and underlain by more clayey and shaly beds. • Careful selection of suitable deposits is required Useful pits are generally of limited extent. 26 | 26 | Introducing the WQBPGs | 30 May 2018
WQ33 Example sandstone ‘pit selection’ • Typically need to extensively prospect for suitable pit • Prospecting generally by backhoe • Pits generally selected on the basis of least thickness of overlying soil (usually <1.5m) • Accessibility for transport (e.g. distance to road). 27 | 27 | Introducing the WQBPGs | 30 May 2018
WQ33 Example sandstone ‘pit processing’ • Generally involves stripping black soil then ripping the sandstone. • Care must be exercised during winning to ensure that only the sandstone beds are actually won. 28 | 28 | Introducing the WQBPGs | 30 May 2018
WQ33 Example sandstone ‘properties’ • Modified test methods should be used Q101 Sample preparation Q101E Pre-treatment Q104D Liquid limit (1 point) of a soil Q106 Linear shrinkage of a soil 29 | 29 | Introducing the WQBPGs | 30 May 2018
WQ33 Example sandstone ‘construction’ • Readily breaks down to a loam • Critical to not over work material during winning of placing trials. 30 | 30 | Introducing the WQBPGs | 30 May 2018
Learnings from 1979 Construction • Deformations and roughness of 140 due to excess rolling with vibrating roller • Roughness appeared as corrugations. 31 | 31 | Introducing the WQBPGs | 30 May 2018
WQ33 Example sandstone ‘history of use ’ • Extensive use of ‘Winton Sandstone’ in the Central West District, including on Landsborough Highway. 32 | 32 | Introducing the WQBPGs | 30 May 2018
WQ35 Paving materials and type cross sections for roads on expansive soils in western Queensland 33 | 33 | Introducing the WQBPGs | 30 May 2018
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