PERFORMANCE ANALYSIS OF GEOSYNTHETICS USED IN ASPHALT REHABILITATION ON URBAN LOCAL HIERARCHY ROADS

PERFORMANCE ANALYSIS OFGEOSYNTHETICS USED IN ASPHALT REHABILITATIONON URBAN LOCAL HIERARCHY ROADSIndustry Project for Logan City Council (QLD)

Matthew W. Coleman

Queensland University of Technology

Student:Mr Matthew W. ColemanEmail:matthew.coleman@connect.qut.edu.au matthewcoleman@logan.qld.gov.auAssessment:Item No. 2 Part ABEng Degree Major: EN40 - Bachelor of Civil and Environmental EngineeringAcademic Supervisor:Mr Bradley Cowan (Adjunct Professor, QUT)Technical Supervisor:Mr Anthony Southon (Senior Engineer, Logan City Council)

Performing Organisation Name and Address:Queensland University of Technology, 2 George Street, Brisbane QLD 4000

Sponsoring Organisation Name and Address:Logan City Council, 150 Wembley Road, Logan Central QLD 4114

A thesis submitted in partial fulfilment of the requirements of the subject BEB801 Project 1 in the Bachelor of Engineering Degree. School of Civil Engineering & Built Environment, Queensland University of Technology, June 2016.The author holds the copyright on this thesis but permission has been granted for QUT Staff to photocopy this thesis without reference to the author.

OBJECTIVEThe objective of the project was to develop decision parameters for the use of geosynthetics in asphalt rehabilitation works to prevent reflective cracking and related defects on urban local roads within Logan City Council.

DELIVERABLESDecisions Matrix for asphalt rehabilitation geosyntheticsThe decisions matrix will provide a listing of the available geosynthetics for asphalt applications to South East Queensland and include selection criteria for different aspects of use, based off the determined decision parameters. The matrix will look at variables including asphalt layer placement, treatment types, road hierarchy limitations, constructability restrictions, usable base materials (e.g. profiled surfaces), and manufacturers specifications, etcetera. The decisions matrix will be a live document where future products can be added or removed to suit advancement in technologies, or further performance findings. Test Site for future testing and monitoringA section of Moffatt Road, Waterford West will be set up as a test site for new geosynthetic(s) chosen as part of the decision parameter refinement of the project. The site will be used for future studies to determine the long-term benefits of the chosen geosynthetic product(s) with respect to performance elements such as, reduction and prevention of reflective cracking, and associated pavement defects.

Project Objective, Scope and Deliverables

Two primary areas of investigation included:Logan City CouncilHistoryTopographySoil profilesUrban local road hierarchyDesign treatment selection and analysis tools

Asphalt Rehabilitation & GeosyntheticsAsphalt rehabilitationPavement surface failure mechanismsTypical asphalt rehabilitation treatments (overlays and deep-lift treatments)Asphalt geosyntheticsAsphalt repair treatments with geosynthetics (interlayer and subgrade treatments)Polyester vs. Glass-fibre geosyntheticsExtension of pavement service life with geosyntheticsGeosynthetics previously used by LCCGeosynthetic products available to South East QueenslandIndustry use of geosyntheticsAlternatives to geosyntheticsCertification avenues for available geosynthetic products

Research Literature Review

Various improvements are needed to LCCs PMS database to ensure that geosynthetics are captured accurately.Additional testing measures for preliminary investigations will help with more accurate asphalt rehabilitation designs.Asphalt Geosynthetics are to be used to mitigate the propagation of bottom-up reflective and fatigue cracking. The geosynthetics will also assist in the reduction of rutting and shoving, while stabilising asphalt pavement layers and extending the structural life of the asphalt pavement.Asphalt repair treatments will include asphalt interlayer and subgrade / base geosynthetics. These treatments will form the initial decision parameter of the decision matrix.Interlayer geosynthetic treatments were proven to be the most beneficial, and therefore will be the main focus of the decision matrix. Subgrade / base geosynthetic treatments have a number of concerns and underlying issues which will require further investigation by LCC and suppliers. Possible future study opportunity. Subgrade / base asphalt geosynthetics will not be discounted from the decision parameter analysis, and will be included in the decision matrix. The test site will provide a good opportunity to test the performance of both glass-fibre and polyester geosynthetics.The extension of asphalt rehabilitation service life with geosynthetics was not able to be accurately determined. However, when in use, geosynthetics will be assumed to provide a 30-50% increase in pavement life, under ideal conditions.Geosynthetic manufacturers may find it beneficial to have their available products certified using Australian standards and testing methods.

Literature Review Preliminary Recommendations

Various stages of qualitative information collection and analysis were conducted, in relation to project performance, operational and system overviews.

The experimental stages included:Review of LCC Asset Systems, used for asphalt rehabilitation works.Observations and recommendations from previous projects.Observations and recommendations (including constructability assessment) of current projects.Test site observations and preliminary investigation results.Analysis of observations, recommendations and literature review material to determine decision parameters and decision matrix.Analysis of test site investigation results, and determination of final asphalt and geosynthetic treatment.Test site implementation measures.

Experimental Method & Analysis

Recommendations:The SMEC PMS coding should be updated so that defects detected on higher profile roads take a greater priority than defects on lower profile roads, due to the associated political risks and larger traffic volumes generally associated with higher profile roads.SMECs pre-determined asphalt treatments should be updated to incorporate asphalt treatments with geosynthetics. In conjunction, the determination of SMECs strength and cost values (for new and old asphalt treatment types) should be revised to reflect more accurate project pricings and asphalt lifespan growth with geosynthetic use, where feasible. Modification to LCCs Standard Specifications to reflect the new asphalt notations specified in MRTS30. The MRTS 30 notations are industry wide and are now incorporated on all current asphalt plant mix designs.Implementation of additional testing methods such as FWD/HWD, PAVEDEF, GPR and TSD etcetera to help save costs by refining the asphalt rehabilitation designs in future years, and assistance with assessing the impacts geosynthetics may have on constructed pavements.Cost-benefit investigation should be undertaken in the coming years, to determine the budgetary effectiveness of additional pre-design testing.Implementation of new treatment types/designs (with revised asphalt thicknesses) to reflect the updated requirements of MRTS30 and also the updated range of geosynthetics available to South East Queensland (Explored further in Section 10, after determination of the decision matrix)LCC should endeavour to keep all asphalt and pavement analysis software up to date, while also keeping current with industry software advancements.LCC should endeavour to keep up-to-date with road condition survey assessment.

Review of Council Asset Systems

Visual inspections were carried out on six previously completed asphalt rehabilitation projects that incorporated geosynthetics.Defects were observed on two streets:

Previous Project Observations

Sports Drive, UnderwoodThird Avenue, Marsden

Visual conditions results summary table:

Previous Project Observations - SummaryStreetSuburbAsphalt TreatmentGeosynthetic TreatmentRoad TypeDefects Observed Since InstallationApprox. Age of TreatmentEXISTING ASPHALT INTERLAYER GEOSYNTHETIC TREATMENTSCompton Road (near Railway Bridge)Woodridge150mm nom. DG ACHaTelit C (placed on fresh AC interlayer treatment)ArterialNil23 monthsSports DriveUnderwood50mm nom. DG14 OverlayHaTelit C (placed on existing AC)CollectorYes (Detailed below). Worst defect rectified 12 months ago.2 yearsSUBGRADE TO ASPHALT GEOSYNTHETIC TREATEMENTSHolmview RoadHolmview150 200mm DG ACTensar AR-GCollectorNil2 yearsThird AvenueMarsden300mm DG ACTensar AR-GLocalLongitudinal cracking at asphalt joint.2 yearsUnderwood RoadRochedale South200mm DG AC with MG Binder (Structural Layers)[Travel lanes only]Tensar AR-GLocalNil2 yearsBarbaralla DriveSpringwood200mm DG AC with MG Binder (Structural Layers) [Travel lanes only]Tensar AR-GCollectorNil~2 years

Recommendations:Further to the asset system review, limitations were found with the SMEC PMS and LCCs exposure to available asphalt geosynthetics, which were transferred onto the past projects. These shortcomings need further investigation and improvement.The observed premature defects primarily occurred due to errors in asphalt paving processes, which will need to be flagged with contractors and monitored in future projects.The defects on Sports Drive confirmed that the minimum asphalt thicknesses over geosynthetics needs to adhere to manufacturers specifications. Cost-saving by reduction of asphalt thickness is not viable for asphalt overlays.

From LCCs 2015/16 Asphalt Rehabilitation Works Programme two primary projects which incorporated geosynthetics were chosen to investigate aspects of constructability, product suitability and design improvements. Projects:Loganlea Road, LoganleaBrowns Plains Road, Browns PlainsVarious issues were encountered with both GlasGrid TF and AR-G products, as shown. On Loganlea Road the GlasGrid TF was removed and replaced with HaTelit C.

Current Project Observations

Geosynthetics in use:Tensar AR-GSaint-Gobain Adfors GlasGrid TFHuesker HaTelit C

Loganlea Road, LoganleaGlasGrid TF Install Issues with milled asphalt surfaceBrowns Plains Road, Browns PlainsTensar AR-G Install Bow waves present after first paver run.

Recommendations:Smooth-mill profilers (micro-milled surfaces) have been removed from the decision parameters due to it being outside of the general scope of works for LCC asphalt rehabilitation. The GlasGrid products incorporated in the decision matrix will be flagged as not suitable for regular milled bituminous surfaces.For HaTelit C, where contractors are inexperienced with the product C170 bitumen is to be used to assist the asphalt crew with geosynthetic adhesion.Further investigation / monitoring of Tensar AR-G as a subgrade asphalt geosynthetic will be required (as the practice is outside manufacturers specifications).Additional testing / monitoring of the current projects is to be undertaken on a regular basis to help assess the suitability and performance of the different geosynthetics. Where defects occur prematurely, further investigation will be required by LCC pavement engineers.Although not listed previously, additional recommendations that congregate from the earlier sections also include,Further training requirements are needed for asphalt crews in relation to the installation of geosynthetics. This will help with mitigating installation issues encountered on site. However, such requests are not entirely up to LCC to decide though they could be considered for future projects, and as part of building LCCs contractor relationships.The addition of hold points (Administrator sign-off required) for tack coat applications and/or geosynthetic roll-out may prove useful to ensure the correct amount or type of tack coat is sprayed, etcetera.LCC pavement engineers to keep up to date with industry movements, products and paving technologies. Where applicable, LCC may even choose to model parts of their updated pavement rehabilitation model off other rehabilitation models.

Current Project Observations - Summary

Test Locations were established on Moffatt Road, Waterford West at two points where the wearing course defects were worst.Before a suitable asphalt treatment with geosynthetic(s) was able to be determined, LCC organised pavement geotechnical testing to determine the appropriate asphalt treatment for Moffatt Road.

Test Site Observations

Test Location ATest Location BTest Location Map

The conclusions from the geotechnical test locations were summarised as:The subsurface conditions at the site generally comprised between 60mm to 65mm of asphalt. Below the asphalt, roadbase gravel was encountered to 0.45m to 0.5m depth. The fill below the roadbase comprise of either silty sand or a mixture of clayey sand and clay. The natural material encountered below the fill comprised of high plasticity clay.The soaked CBR values were determined, where the lowest CBR value encountered was 1%.

Test Site Geotechnical Investigation/Testing Results

Test Location A Visible CrackTest Location B Visible Crack

Decision Parameters & Decision Matrix [Project Deliverable 1]

Section A: GlasGrid Compogrid (Glass-Fibre)Section B: No geosynthetic reinforcement [Control]Section C: GC50-II (Polyester)

Test Site Implementation Moffatt Road, Waterford West [Project Deliverable 2]

Geotechnical testing results were incorporated into CIRCLY analysis. The final treatment design was determined as:

100mm AC14 (DG14) placed in two separate layers, with asphalt geosynthetic to be placed at the interlayer (mid-point) of the two layers.

The test site will allow the comparison of both PET and Glass-fibre geosynthetics.

Post-construction, the test site will undergo various testing including FWD & GPR to investigate pavement properties and geosynthetic impacts over time.

LCC pavement engineers are to follow the testing regime developed as part of the report.

Thank you.