Clay Soil Stabilisation – delivering sustainable long term ground improvement

Overview

Clay – The Problem

The presence of clay is viewed by pavement designers as a risk to be mitigated. Pavements constructed on expansive clay sub-grades, universally suffer from clay soil heave (which is the expansion of clays due to the ingress of water). Commonly, pavement designers address this risk with a range of techniques such as lime or cement stabilisation, the use of membranes to prevent moisture migration within the sub-grade, and additional drainage.

Clay – The Solution

TERRA-3000® transforms clay into a high-performing asset. Instead of remove and replace, many clay soils can be treated insitu. TERRA-3000® permanently and irreversibly breaks down the capillary action of water within the cohesive fines during treatment. Also, with appropriate compaction, treated soil particles can more closely associate.

Clay – The Result

The resultant treated layer is no longer prone to the problems associated with the ingress of water. Pavement strength is markedly improved. TERRA-3000® is not a binder or binding agent, meaning that pavement layers which are treated with TERRA-3000® are considered unbound and retain the advantage of flexibility at strength over bound pavements.

The use of TERRA-3000® for stabilisation of cohesive soils can deliver equivalent pavement performance whilst substantially reducing pavement thickness by the creation of a base-grade layer made from in-situ materials. This leads to significant reductions in material removal and replacement compared to a standard pavement design.

Using TERRA-3000® reduces carbon emissions compared to typical pavement design and construction. Lower site carbon emissions result from greater use of in-situ materials, reduced use of imported construction materials (e.g. gravels), less transport movements and the simplified construction methodology. For a given project, manufacture and delivery of TERRA-3000® has a very low carbon footprint, with further sustainability benefits in that it is non-leaching, leaves no residue, is lime and cement free, and has no airborne particulates, meaning it is safe for operators to use and suitable for sensitive environments.

TERRA-3000® is an amine compound soil stabiliser (electro-physical) that is applied as a liquid concentrate diluted with water during treatment. A proportion of clay and silt fines are required for TERRA-3000® to function and soils with a wide range of clay contents can successfully be treated.

To find out more, Contact Us.

How it Works

The Science

TERRA-3000® requires the presence of clay and silt fines to improve the mechanical and hydraulic performance of soil. Soils with a wide range of clay content can successfully be treated.

TERRA-3000® is a chemically engineered Amine based liquid concentrate that is diluted with water during treatment. It acts as a catalyst to permanently and irreversibly alter the properties of soil colloids.

TERRA-3000® produces an electro-physical reaction (ion exchange) in the cohesive fines (clays, and silts) during treatment. The ion exchange reduces the surface tension of water in soil colloids, so that the barrier film surrounding colloids is dispersed.

As a result, treated soil particles can more closely associate during compaction and the capillary action of the treated soil particles is effectively broken down.

It is not a binder or binding agent, meaning that pavement layers which are treated with TERRA-3000® are considered unbound and retain the advantage of flexibility at strength over bound pavements.

When applied as directed to suitable materials, TERRA-3000® increases the stiffness of stabilised soils and prevents the ingress of water.

Material Suitability

TERRA-3000® requires the presence of clay and silt fines to improve the mechanical and hydraulic performance of soil. It is suitable and safe to use in environmentally sensitive areas such as rivers and lakes. It doesn’t leach and leaves no reside.

We assist clients to determine the suitability and performance outcomes using TERRA-3000® for each particular project. A sound starting point is to perform Particle Size Distribution (PSD) and Hydrometer tests. The hydrometer test quantifies the clay and silt fractions within the candidate materials.

A model particle distribution has an even particle distribution range between 0.002 mm and 37.5mm. Larger fractions (> 50 mm) are crushed prior to treatment.

However, TERRA-3000® can be used to successfully treat a wide range of soil profiles with varying clay contents.

Applications

TERRA-3000® is suitable for a variety of stabilisation applications.

Pavement applications include:

  • New Construction and Rehabilitation
    • Pavement maintenance including heavy patching
    • End of life pavement recycling
    • Sustainable alternative to aggregate sheeting
    • Water / flood resilience, erosion control, drainage
  • Roads including:
    • Mine haul roads (above and below ground)
    • Service roads and access tracks
    • Road shoulders to protect from moisture ingress
  • Parking areas
  • Rail (track beds and formations)
  • Airports (runways, taxiways and aprons)
  • High availability / disaster recover / on demand infrastructure – roads, hardstands, airstrips
  • Hardstands (port, loading areas etc)

Other applications include:

  • Temporary works platforms
  •  Dams, dykes, levees and canals:
    • including dam wall raises
    • seepage control / containment to contain the flow of water and to minimise erosion
  • Land development
  • Defence

TERRA-3000® is suitable and safe to use in environmentally sensitive areas such as near rivers and lakes.

Pavement Design

The use of TERRA-3000® to improve the mechanical and hydraulic performance of in-situ soils has a profound impact on traditional pavement design. The diagram below gives an indication of the reductions in pavement depth and thickness in wearing course made possible by stabilisation of in-situ soils using TERRA-3000®.

Our best practice approach to support maximum savings in construction cost and the most sustainable outcomes, features a single high performing base-grade layer treated with TERRA-3000®. That said, TERRA-3000® treated layers can be targeted to both complement or supplement traditional pavement designs.

Treatment & Testing

Pavement construction with TERRA-3000® uses typical civil construction equipment. Ideal application equipment includes:

  • a mechanical stabiliser enables a uniform rate of application and thorough mixing
  • a heavy multi-tyre roller for the best compaction outcome

TERRA-3000® is a liquid concentrate that is diluted with water during treatment at a typical rate of 1:20.

  • Treatment is as simple as:
  • Rip
  • Apply
  • Mix
  • Shape
  • Compact

Insitu materials are loosened (rip) and brought to optimal moisture content (OMC) with the addition of water, or in damp settings, allowed to aerate until optimal moisture content is reached. Diluted TERRA-3000® is evenly applied either with a mechanical stabiliser (apply and mix) or using a water cart and thoroughly mixed by grader blade. Treated materials are then shaped and compacted using predominately static compaction (shape and compact).

We train civil construction crews on the application of TERRA-3000® using their own construction equipment.

TERRA-3000® is safe to use, both for those applying it and for the environment. Adhere to the instructions contained in the Material Safety Data Sheet (MSDS) and product labelling. For easy handling, TERRA-3000® is supplied in 1 litre bottles, 25 litre containers and 1,000 litre intermediate bulk containers (IBC’s).

Immediate performance feedback (through insitu tests) and adjustment is possible during construction. Suitable insitu testing methods include the Light Weight Deflectometer (LWD) and Plate Load Test (PLT).

Blogs

As part of our commitment to enabling our clients to push forward with confidence, we are now offering TERRA-3000® – a transformational long lasting sustainable soil stabilisation solutions for soil improvement. TERRA-3000® facilitates the creation of a base-grade from in-situ materials at a lesser depth, delivering better performance at a lower cost, than traditional pavement design. TERRA-3000® transforms […]

Additional Information

Performance Benefits

Performance results are largely driven by the suitability of the soil profile to be treated, the treatment depth and the application process. The objective is a high strength flexible unbound pavement. Performance improvements include:

  • Reduced Plasticity Index (PI)
  • Reduced permeability
  • Reduced capillary action
  • Reduced shrink / swell
  • Post roller compaction, continued improvement under load/traffic (improved compaction / consolidation / agglomeration under load)
  • Lower Proctor Optimum
  • Higher density
  • Significant increase in stiffness and in-situ modulus.

From a practical perspective, the treatment with TERRA-3000® is compelling:

  • Permanent and irreversible
  • Once off treatment
  • No curing time
  • Materials with a wide range of clay contents can be successfully treated
  • Immediate performance feedback (through insitu tests) during construction
  • Minimal damage from water ingress due to effective loss of capillary action in treated pavement layer.

Ideally, a minimal wearing course is placed to protect the treated surface from mechanical load and surface abrasion.

SAVINGS

Stabilisation with TERRA-3000® typically leads to the following:

  • Use / re-use of insitu materials
    •  Less remove and replace
  • Reduced aggregate demand
  • Reduced transport movements
  • Time saving construction / treatment method
  • No curing time
  • No specialist construction equipment required
  • Reduced maintenance requirements
  • Extended pavement life

Credentials

Environmental & Sustainability Credentials

The use of TERRA-3000® for stabilisation of cohesive soils can deliver equivalent pavement performance whilst substantially reducing pavement thickness by the creation of a base-grade layer made from in-situ materials. This leads to significant reductions in material removal and replacement compared to a standard pavement design.

Using TERRA-3000® reduces carbon emissions compared to typical pavement design and construction. Lower site carbon emissions result from:

  • greater use of in-situ materials
  • reduced use of imported construction materials (e.g. gravels)
  • less transport movements
  • the simplified construction methodology.

For a given project, manufacture and delivery of TERRA-3000® has a very low carbon footprint.

Further sustainability benefits include that it is non-leaching, leaves no residue, is lime and cement free, and has no airborne particulates, meaning it is safe for operators to use and suitable for sensitive environments.

Trusted by our clients

CPB Contractors
Select Plant Hire (Laing O'Rourke)
Department of Defence
Royal Australian Air Force
Department of Transport and Main Roads QLD
Progress Rail Services
GHD
Fulton Hogan
STATS Australia
Golder Associates
Construction Sciences Pty Ltd
FSG Geotechnics
Downer EDI Logo
Fletcher Construction
Road Science
Civil Innovation
Global Synthetics
SMEC
Tailcon Projects
Chadwick Geotechnics
WANT Geotechnics
A&Y Associates
Ground Science Pty Ltd
Tasman Geotechnics
CPTS
Civiltest Pty Ltd
Tonkin & Taylor
Douglas Partners
Queensland Rail
CivilPlus Constructions Pty Ltd
Rio Tinto
Fortescue Metals Group
First Solar
Colas Australia Group
Wakefield Regional Council
CMW Geosciences
LBS Engineering
Protest Engineering
Red Earth Engineering
WSP Australia
Boom Logistics
Global Engineering & Construction
MPC Kinetic
South 32
Transport for NSW - Sydney Trains
Future Generations
Senversa
RJE Global
Macquarie Geotechnical
Kleinfelder
Jacobs
Geo Environmental Solutions
ENGEO
Durkin
Contract Power Group
Bland Shire Council
Betta Roads
Arcos Group
SMS Geotechnical
Aurecon
ADE Consulting Group
Australian Rail Track Corporation Ltd
Plateway Pty Ltd
Butler Partners Pty Ltd
4D Geotechnics Pty Ltd
AMB Geotech SQS Pty Ltd
ATC Williams Pty Ltd
Australian Geotechnical Testing
Australian Soil and Concrete Testing Pty Ltd
BHP Nickel West
Black Insitu Testing
Bloxam Burnett & Olliver Ltd
Calibre Global
Cartwheel Minerals Pty Ltd
CMT Engineers
Consolidated Power Projects Australia
CQUniversity Australia
D&N Geotechnical
Dynamic Compaction Solutions
ETS Geo
Evolution Mining: Northparkes
Finnish Overseas Consultants Ltd
Galt Geotechnics Pty Ltd
Geolab
Geotech International
Geotechnical Testing Services Pty Ltd
HEB Constructions
Hunter Civilab
Keller Pty Ltd
KMK Geotechnics
Local Geotechnics
Mitchell Water Australia
Ora Banda Mining
Pardo Engineering
Pearce Geotechnical
Powerlink
Qualtest Laboratory Pty Ltd
Queensland University of Technology
Te Ahu a Turanga Alliance _ Fulton Hogan

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Insitutek Blogs

We find clients are often looking for ways to improve geotechnical testing outcomes and do it more efficiently at the same time. This drives their buying decision making. Australian Soil and Concrete Testing (ASCT) was a case in point when they were searching for Plate Load Test equipment for their upcoming Collector Wind Farm project. Some of the things that motivated them include: […]

We are excited to introduce the addition of a new Liquefaction Risk Estimation module in WebSprint©. Paired with our cutting-edge products, PANDA® and GRIZZLY®, this module enables you to assess the liquefaction risk of soils exposed to seismic stress. PANDA® Instrumented DCP: This cutting-edge tool provides dynamic penetrometer soundings, delivering precise data crucial for seismic risk evaluations. GRIZZLY® […]

The Australian Geomechanics Society is gearing up for a series of geotechnical events across VIC, WA, NSW, and SA-NT. We are thrilled to inform you that we will be sponsoring and attending these exciting geotechnical events, and we would love for you to join us. It’s a fantastic opportunity to catch up, explore our booth (VIC), and stay informed about […]