Presentation as partial fulfilment of the requirements of the subject BEB801 Project 1 at Queensland University of Technology. Industry project with Logan City Council. (Please note SlideShare may have issues with the embedded audio)

1. PERFORMANCE ANALYSIS OF
GEOSYNTHETICS USED IN ASPHALT REHABILITATION
ON URBAN LOCAL HIERARCHY ROADS
Industry Project for Logan City Council (QLD)
Matthew W. Coleman
Queensland University of Technology

2. Student: Mr Matthew W. Coleman
Email: matthew.coleman@connect.qut.edu.au
matthewcoleman@logan.qld.gov.au
Assessment: Item No. 2 – Part A
BEng Degree Major: EN40 - Bachelor of Civil and Environmental Engineering
Academic 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.

3. OBJECTIVE
• The 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.
DELIVERABLES
Decisions Matrix for asphalt rehabilitation geosynthetics
• The 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 monitoring
• A 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

4. • Two primary areas of investigation included:
• Logan City Council
• History
• Topography
• Soil profiles
• Urban local road hierarchy
• Design treatment selection and analysis tools
• Asphalt Rehabilitation & Geosynthetics
• Asphalt rehabilitation
• Pavement surface failure mechanisms
• Typical asphalt rehabilitation treatments (overlays and deep-lift treatments)
• Asphalt geosynthetics
• Asphalt repair treatments with geosynthetics (interlayer and subgrade treatments)
• Polyester vs. Glass-fibre geosynthetics
• Extension of pavement service life with geosynthetics
• Geosynthetics previously used by LCC
• Geosynthetic products available to South East Queensland
• Industry use of geosynthetics
• Alternatives to geosynthetics
• Certification avenues for available geosynthetic products
Research – Literature Review

5. • Various improvements are needed to LCC’s 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

6. 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

7. 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.
• SMEC’s pre-determined asphalt treatments should be updated to incorporate asphalt treatments with
geosynthetics. In conjunction, the determination of SMEC’s 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 LCC’s 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

8. 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, Underwood
Third Avenue, Marsden

9. Visual conditions results summary table:
Previous Project Observations - Summary
Street Suburb
Asphalt
Treatment
Geosynthetic
Treatment
Road Type
Defects Observed
Since Installation
Approx. Age of
Treatment
EXISTING ASPHALT INTERLAYER GEOSYNTHETIC TREATMENTS
Compton Road (near
Railway Bridge)
Woodridge
150mm nom. DG
AC
HaTelit® C
(placed on fresh AC
– interlayer
treatment)
Arterial Nil 23 months
Sports Drive Underwood
50mm nom. DG14
Overlay
HaTelit® C (placed
on existing AC)
Collector
Yes (Detailed
below).
Worst defect
rectified 12 months
ago.
2 years
SUBGRADE TO ASPHALT GEOSYNTHETIC TREATEMENTS
Holmview Road Holmview
150 – 200mm DG
AC
Tensar® AR-G Collector Nil 2 years
Third Avenue Marsden 300mm DG AC Tensar® AR-G Local
Longitudinal
cracking at asphalt
joint.
2 years
Underwood Road
Rochedale
South
200mm DG AC
with MG Binder
(Structural Layers)
[Travel lanes
only]
Tensar® AR-G Local Nil 2 years
Barbaralla Drive Springwood
200mm DG AC
with MG Binder
(Structural Layers)
[Travel lanes
only]
Tensar® AR-G Collector Nil ~2 years
Recommendations:
• Further to the asset system review, limitations were found with the SMEC PMS and LCC’s 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.

10. From LCC’s 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, Loganlea
• Browns Plains Road, Browns Plains
Various 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-G
Saint-Gobain Adfors GlasGrid® TF
Huesker HaTelit® C
Loganlea Road, Loganlea
GlasGrid® TF Install Issues with milled asphalt surface
Browns Plains Road, Browns Plains
Tensar® AR-G Install
Bow waves present after first paver run.

11. 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 manufacturer’s 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 LCC’s 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

12. 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 A Test Location B Test Location Map

13. 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 Crack Test Location B – Visible Crack

14. Decision Parameters & Decision Matrix [Project Deliverable 1]

15. • 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.

16. Thank you.