Binders
Cement | Lime | Bitumen | Chemicals | Suppliers

A binder is a material used for the purpose of improving the properties of a subgrade or pavement material.  In Australia, most binders used for road stabilisation are in a powder format and the main liquid binder is bitumen.  In some situations, additives are used to enhance the construction process or provide additional long term prosperities to the stabilised materials. 

Stabilisation binders are typically categorised in terms of their main constituent.  AustStab categorises binders in the following format:

Cementitious: Consists of a wide range of cement and blends, and includes Portland (GP) and blended cements (GB) cements or contains a combination of pozzalan material and cement and/or lime , such as fly ash and lime and slag (ground granulated blast furnace slag) and lime

Lime: Hydrated lime [Ca(OH)2], quicklime [CaO] and lime slurry.

Bitumen: Class C170 bitumen is typically used in stabilisation and in Australia either foamed bitumen or emulsion is used.  Bitumen stabilisation may incorporate a supplementary additive such as lime or cement

Chemical: Proprietary products primarily include polymers and salts.

In specifications, the binder is specified as percentage of the mass of the stabilised material and not as a volume.

 

Cement

There is a wide range of cement types and blends in Australia and each has different characteristics.  The principal cement types available are as follows:

Type GP - General Purpose Portland Cement

Type GB - General Purpose Blended Cement

General purpose cements are produced from a mixture of calcium carbonate, alumina, silica and iron oxide which, when calcined and sintered at high temperatures gives a new group of chemical compounds capable of reacting with water.  The composition of individual cements can vary depending on the nature and composition of the raw materials being used.

In Australia special purpose cements are not commonly used in stabilisation of subgrade soils or pavement materials

Cementitious binders contain a pozzolanic material which is a siliceous or alumino siliceous in a finely divided form.  In the presence of moisture the pozzolanic material  chemically reacts at ordinary room temperatures with calcium hydroxide released by the hydration of Portland cement or lime to form compounds possessing cementitious products.  The common pozzolanic materials include fly ash and iron and steel slags, which may be combined with hydrated lime or GP cement to form cementitious binders.

Cementitious binders provide an alternative to GP cement, on the grounds of economy or for extended working time for compaction and finishing.

Lime

The word 'lime' is a generic term used to describe either quicklime or hydrated lime (but not limestone or agricultural lime).  Quicklime manufactured in Australia is processed through a fluid bed, rotary or vertical shaft kilns.  The manufacture of quicklime involves the heating of excavated limestone in a lime kiln to temperatures above 900°C resulting in carbon dioxide being driven off and calcium oxide being produced.

Quicklime’s ability to form alkaline solutions / suspensions in water is key to its being able to modify certain soils in such a way that the end result is a benefit to road engineers.

At temperatures below 350°C, the calcium oxide component of quicklime reacts with water to produce hydrated lime (calcium hydroxide) as well as liberating heat.  This process is called 'hydration' and should be strictly differentiated from the term 'slaking' which involves the production of a dispersion of Ca(OH)2 in water (i.e. a milk of lime or lime putty).  However, this distinction has blurred over time and the expression 'slaked lime' has come to be used as a generic term for hydrated lime, milk of lime and lime putty.  In construction, when quicklime is spread onto the road surface, the application of water onto the quicklime is commonly called 'slaking' in Australia.

Lime slurries have been used in Australia but are rarely used for road stabilisation due to the cost and problems caused by adding more water to an already wet material.

For more information about lime and the benefits of lime stabilisation refer to the following documents:

Lime stabilisation practice - A technical note on lime stabilisation covering lime production through to construction.  Click here to view PDF file (319kB).

Model specifications - Lime stabilisation specifications for local roads for subgrade and base materials. Click here to view details.

Hydrated lime to quicklime spread rates - A spreadsheet to convert hydrated lime used in laboratory testing to field quicklime spread rates.  Click here to download EXCEL 2003 file (30kB).

Cleaning vehicles - A tip to cleaning vehicles driven over lime and cement during road stabilisation construction is provided to assist members when this occurs.  Click here to view more information.

Bitumen

Bitumen is used as either an emulsion or in a foamed state.  Foamed bitumen is a mixture of air, water and hot bitumen and the typical quantities are 98% bitumen, 1% water and up to 1% foaming agent.  When hot bitumen (160 to 200°C) comes in contact with cold water (15 to 25°C) the mixture expands to greater than 10 times its original volume and forms a fine mist or foam.  Bitumen emulsion is a mixture of bitumen (40%) and water.  Both foamed bitumen and emulsion use Class 170 bitumen and they are used with a supplementary binder, such as lime or cement.

The Association has a technical guide on foamed bitumen stabilisation and specifications, and these may be accessed from this site.  An interim structural design approach for foamed bitumen may be found in a paper titled (click here) and research work on this topic is summarised in a series of papers and reports on the pavement analysis page.

Chemicals

Chemical binders are all those binders other than cementitious, lime and bitumen.  The following categorises are used by AustStab and Austroads to define the mainstream chemical binders, and their reaction with subgrades and pavement materials.

Polymers:               PVA or PVC. polymers and copolymers bond fine particles and impart hydrophobic properties to soil. Refer to the AustStab technical note on use of polymers in stabilisation.

Organic:                 Common organic binders are Tall oil, sulphonated lignin and di-limonene.  Tall oil is specific to the type of soil or pavement material source and results in adhesion of the fine particles to interlock larger aggregates. They generally require adequate material grading and plasticity and cement or lime can be added.

Ionic:                      Electro chemical charge imparted to clay platelets. The binders are very material dependent and slow reacting.

Salts:                      Water attracting (hydroscopic) - magnesium chloride most common. Require moisture (humidity) to be effective. These binders require frequent reapplication following rain.

Biological:              Microbes consume clay to excrete polymeric residue. High clay contents required. These types of binders are not commonly available in Australia

Binder suppliers

The following companies are members of AustStab and supply quality binders for soil stabilisation and road recycling. The companies are listed alphabetically.

For more information on contacting AustStab binder suppliers.

Adelaide Brighton Cement

Adelaide Brighton Cement Limited (ABCL) operates binder production plants in Geelong (Geelong Cement), Perth (Swan Portland Cement), Birkenhead and Angaston (South Australia) and there is a continuous development of purpose designed binders at all of these locations.

Typically, ABCL offers a variety of cement and lime binders incorporating fly ash and granulated blast furnace slag in varying proportions. Details of the most used pavement stabilisation binders are listed below:

Geelong

Swan Portland

Birkenhead

Angaston

All ABCL blended products are currently manufactured by controlled proportion intergrinding and blending to ensure that a homogeneous finished product is achieved. Various other blending systems are currently under evaluation and will be commissioned at various sites in the near future. These plants will allow blended binders to be produced in specified proportions to suit the particular application under consideration.

For further information please contact:

South Australia: D Bonnett TEL: (08) 8300 0300 FAX: (08) 8341 1591

Western Australia: Mike Harper TEL: (08) 9366 2200 FAX: (08) 9361 8515

Cement Australia

Cement Australia produces consistent high quality quicklime and hydrated lime and distributes these products throughout Queensland. Tailor-made 2 and 3 component blends incorporating lime, fly ash, cement and other binders are available for specific stabilisation applications from a purpose built blending plant in Rockhampton. For further information please contact Jeff Charteris on 07 3335-3060 or jeff.charteris@cemaust.com.au or Paul Ribinsky for lime on 07 4932 1710 or paul.ribinsky@cemaust.com.au

 

Blue Circle Southern Cement

Blue Circle Southern provides a wide range of products to meet many of the differing soil types and construction techniques used by industry.

The binding systems incorporate fly ash and ground-granulated iron blast furnace slag with the activator being hydrated lime or Portland cement, and each has particular construction advantages. For instance, the Portland cement blends offer shorter working time, and the potential advantage of no overnight rutting of stabilised pavements which become trafficked soon after construction. The lime based system offers the advantages of long and extended working times, and the ability to recompact.  Should the construction initially result in pavement densities being insufficient, these lime-based binders allow recompaction due to the their longer setting time characteristics. Additionally, the construction of large jobs can be carried out because of the extended working times even if construction equipment is limited.

The supply of stabilising blends includes Stabilment and 70 lime blend (both incorporating hydrated lime) and Slag Stabilising Cement (SSC40), Roadment,  Slagment using Portland cement and Pozzoment (a cement/fly ash blend).

Blue Circle Southern also has separate quicklime and hydrated lime products for stabilisation of heavy clay materials and subgrade treatment. The quicklime is produced at Marulan and the lime is a soft burnt highly reactive product with calcium oxide availability (CaO) in excess of 90%. The production of hydrated lime using this highly reactive quicklime results in a very fine particle sizing which is utilised to good advantage in the other stabilisation products.

The majority of these binders are available throughout NSW.  In many instances, the selection of the appropriate ingredient has been specifically targeted by region from a large data base, developed over many years of experience.

Should you have further questions about products suitable to your specific application, contact Ron Clarkson on TEL: (03) 5240 6066 or FAX: (03) 5241 8310.

Hyrock

In the early 1990s, Hyrock constructed a 25 m3 Ribbon Merge Cell (RMC) batch blender.  This is one of the largest in Australia and supplies stabilising binders to many government authorities and contractors.

 The RMC Batch Blenders have ‘design-a-blend’ capability, producing blends of lime, fly ash, ground slag and cement in any ratio desired by the road pavement designer.  Advanced computer control ensures blends are produced to within 1% accuracy of customer requirements.

  Hyrock has developed a proprietary binder based on a by-product produced by the coal fired lime kiln.  The product is known as DiCal and consists of very finely divided quicklime, fly ash and limestone blended within the rotary kiln at temperatures up to 1000o C.  DiCal is inexpensive and has unique binding properties not found in other cementitious binders.

 The location of the Charbon Works and Port Kembla Terminal with their blending, storage and loading facilities ensures the efficient production and dispatch of lime, fly ash and cementitious binders throughout NSW.

  For more information about Hyrock, contact Bill Hines on (02) 4276-4276 or refer to www.hyrock.com.au

Independent Cement and Lime

Slag is a creation of the high temperature combination of minerals, which are formed over thousands of years, and bought together when producing iron.

Most of the granulated slag produced from the above process at BHP in Newcastle, is predominantly shipped to Port Melbourne in Victoria. It is processed here for blending the extensive range of stabilants that Independent Cement and Lime (ICL) produce for Victoria and New South Wales.

In 1993, ICL commenced supplying the road stabilisation industry with slag-based blends to suit design specifications of individual jobs. ICL has the capability to provide a limitless range of blends. Binders available from ICL include any combination of the following materials:

Binders from ICL are marketed under Steelpave for the slag-lime and slag-lime-fly ash blends, and Steelcement for the cement-slag blend.

The most frequently requested binders consist of the following blended materials:

Each of these binders has individual characteristics, more conducive to different pavement materials and the environment, in terms of rainfall etc.

For further information please contact:

Victoria: James Howard TEL: (03) 9676 0000  FAX: (03) 9646 4954

Newcastle: Gordon Dobson TEL: (02) 4964 4208 FAX: (02) 4964 4328

 

POLYROAD

For further information please contact Max Wallis on 02 6056 5557 or max@polyroad.com.au or visit the web site at www.polyroad.com.au

Shell Bitumen

Shell Bitumen is the largest supplier of petroleum bitumen in Australia and offers nationwide coverage from a network of refineries, manufacturing plants and depots. This supply network is strategically sited to ensure that products for specific applications are readily available. Shell Bitumen places emphasis on customer service, product quality and innovation, and draws on extensive laboratory facilities for product testing and development work. Local technical staff are available for immediate assistance and this service is supported by the expertise of Shell International, the world's leading bitumen supplier.

Shell Bitumen produce the Mexphalte range of high performance paving grade bitumens which exceed the specification limits of AS2008, and Anionic Slow Set emulsions to AS1160 through contract manufacturers, both of which are suitable for use in stabilisation works. Shell strongly supports industry associations and government bodies in the promotion of the efficient and effective use of bitumen.

For further information on Shell Bitumen contact

  • Victoria & NSW: Paul Prendergast (03) 8823 4452 (03) 8823 4048
  • SA, WA and NT: Scott Jenssen (08) 9432 1473 (08) 9432 1252 
  • Queensland: Trevor Hodge (07) 3384 5220 (07) 3364 5317
  • Head Office: Nigel Preston TEL: (03) 8823 4451  FAX: (03) 8823 4048

    • Sunstate Cement

    Roadblend is a special purpose cement produced primarily for road base and subgrade soil stabilisation by Sunstate Cement Ltd in Brisbane.

    It is manufactured by grinding Portland cement clinker in carefully controlled proportions with granulated iron blast furnace slag which has been selected for its particular mineral and chemical qualities.

    It is compatible with most granular and many plastic materials and can replace Type GP cement or hydrated lime in most applications.

    Roadblend may be used to stabilise materials with addition rates likely to be in the range of 2% to 5% by weight of suitable untreated material (depending on the plasticity of the material).

    Roadblend may be used in both the insitu method and the pugmill method. The mixing of the pavement materials should be carried out using purpose built stabilising equipment.

    To ensure full strength development, it is essential that curing the cement stabilised layer is carried out for a period of at least seven days. Curing methods such as regular, uniform spraying with a water cart and the application of a bituminous prime coat membrane are common.

    For further information on Roadblend contact the Sales Manager at Sunstate Cement on TEL: (07) 3895 9827 or by FAX: (07) 3895 9801.

    Unimin Australia

    Unimin Australia operates lime kilns for the production of both quicklime and hydrated lime at:

    Quicklime and Hydrated Lime products are used primarily on soils that are predominantly clay based. They are also used in the stabilisation of subgrade material. There are clear advantages in using lime products, such as an extension of the length of working time and a reduction in plasticity index (PI).


    For further information, please contact:
    Queensland John Christensen Ph (07) 3278 6322 Fax (07) 3278 6229
    NSW Paul Keane Ph (02) 6769 5501 Fax (02) 6769 5707
    Victoria Murray Joseph Ph (03) 97350644 Fax (03) 97396189
    Tasmania Tim Jones Ph (03) 6363 1187 Fax (03) 63631188

    [12 June 2008]