Colour | Concrete Properties | Mix Proportions | Mortar Properties | Cement Properties | Compatibility

Use of Sunlite off-white cement is a key factor in the striking appearance of the coloured retaining wall
panels and sound barriers on the Pacific Motorway at Nerang.

Sunlite off-white cement provides a wide range of attractive and distinctive architectural finishes for buildings, bridges, pavements and other structures or facilities. Produced by Sunstate Cement in Brisbane, Sunlite is a high early strength cement complying with AS 3972, Type HE.

Sunlite is produced from an especially manufactured light-coloured Portland cement clinker which provides its unique colour.

When combined with selected sands, aggregates and oxides, Sunlite provides an extremely diverse and architecturally satisfying range of finishes in brick and blockwork mortar, rendering, exposed aggregate pavements, panels and terrazzo.

As well as the coloured noise barriers on the Pacific Highway at Nerang, other high-profile applications which demonstrate the aesthetic and structural qualities of Sunlite off-white cement include the airport control tower and the facade of the Marriott Hotel in Brisbane.

COLOUR
Colour control in concrete. The colour of concrete made with Sunlite will be influenced by the mix design, water content and the colour of the fine aggregates. For projects with a lengthy construction period use sands that have an acknowledged colour consistency, or those which can be stockpiled in sufficient quantities.

Slump consistency is essential for colour control.
Concrete which fails to comply with the slump tolerances contained in AS 1379 should not be placed in areas where colour control is critical.

CONCRETE PROPERTIES
Mix Design. The cement content for each grade of concrete will depend on the nominated target strength, and colour desired.

AS 3600 "Concrete Structures" recommends minimum strengths to achieve adequate concrete durability for more severe exposure conditions, eg. Exposure classification B1 (locations close to the coast) requires a minimum N32 MPa concrete.

For site mixed concrete the following mix proportions are suggested:

Mixing. AS 1379 gives requirement for material quality and mixing ready-mixed concrete. Recycled water may be used only where testing can demonstrate compliance with the relevant section of AS 1379.

Dissolved salts and organic matter may adversely affect the strength, durability and appearance of the concrete. Salt and organic matter in sand will have a similar detrimental effect.

Compressive strength development. The strength development of Sunlite cement is primarily dependent on the water - to - cement ratio. The following graph gives indicative data on the strength development of concrete containing Sunlite cement.

Age at test
Water/cement ratio = 0.59
Note: Data is based on mixes containing no admixture. Use of
admixtures, fly ash etc. will alter the strength development
characteristics of concrete containing Sunlite cement.

Effect of excess water. Use only the minimum amount of water to mix and place the concrete. The following graph shows the reduction in compressive strength of concrete with increased water addition.

Water Added
Indicative representational only. Not to be used for calculation.

The porosity of concrete made with excess water is also increased resulting in a structure with less resistance to chemical attack.

Other factors which affect the strength and durability of concrete containing Sunlite concrete are:

• Concrete mix design, including admixtures

• Temperature (ambient and concrete)

• Entrained air content

• Compaction of concrete

• Curing

Placing. AS 3600 gives requirements for handling, placing and finishing concrete.
Minimum cover to reinforcement is 20 mm for the lowest exposure classification. The cover needs to be increased where concrete is cast against the ground, for fire resistance and for exposure classifications other than A1.

Curing. A minimum curing period of seven days is recommended for all exposure classifications. Concrete should be maintained in a moist condition where practicable. Use of water-application techniques, such as water sprays and wet sand or water retaining techniques, such as polyethylene sheets or curing compounds, are recommended. Curing should begin as soon as the selected technique allows.

For normal-class concrete, curing can produce a compressive strength 80% to 100% greater than concrete not subjected to curing. Water application or water retaining curing is more effective for lower grades of concrete. For concrete strengths of 40 MPa and above, curing is equally important. However, the type of curing mechanism is considered to be less critical.

Curing also will affect other concrete properties including:

• Reduction in the potential for plastic cracking.

• Improvement in surface quality, durability and impermeability.

• An improvement in abrasion resistance, particularly in higher grades of concrete.

• Reduction in the carbonation rate.

Variations in the duration of curing or the uses of different curing methods may affect the initial colour of concrete.

Quantities of sand sufficient to complete the project should be stockpiled and protected from contamination.

MORTAR PROPERTIES
Colour control in mortar. For a light off-white colour, best results are achieved by the careful selection of a white bricklayer's sand plus lime. Coloured bricklaying sands may be used to produce some natural coloured mortars, e.g. creams to yellow.

Mix proportions must be kept consistent to minimise variations of colour. Sand, cement and water quantities for each batch must be measured out using a bucket or other measuring device. Maintaining a constant water-to-cement ratio and sand-to-cement ratio is critical for colour control.

Mix Design. The following table provides examples for use of Sunlite cement for various exposure conditions.

Batching. AS 3700 requires batching to be carried out using a bucket or other approved measuring device. Accurate measurement of each material, including water, is essential to produce a consistent product.

Additives. If plasticisers are used they must be added strictly in accordance with the manufacturer's recommendations and be clear of any colouring. A serious loss of bond strength may occur if substitutions are used or products are overdosed.

Hydrated lime is recommended to improve workability and to produce a lighter coloured mortar.

CEMENT PROPERTIES
The Following table provides an example of Sunlite off-white cement properties:

COMPATIBILITY
Sunlite cement may be mixed or blended with other cements complying with AS 3972. It also may be blended with fly ash complying with AS 3582.1.

Please Note: Blending other products with Sunlite cement is not recommended where colour control is required.

Sunlite cement is compatible with admixtures complying with AS 1478. Some admixtures may affect the consistency of the concrete colour or cause staining. Refer to your admixture supplier for advice.

WORKING INSTRUCTIONS
Storage. Contact with air and moisture will cause hydration of the cement and alter the cement properties. The 'shelf life' of Sunlite cement is therefore dependent on the storage conditions. Bagged product should be stored off the ground and stacked to allow freecirculation of air. Bags are not waterproof. It is recommended that Sunlite cement be retested prior to use if the age of the cement exceeds three months.

Handling. A Material Safety Data Sheet can be obtained here.

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