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Conplast SP420 - Conventional superplasticising additive for high workability

Conventional superplasticising additive that allows extending the period of maintenance of workability.

Consumption: 0.35 - 1.0% of the weight of the cement.

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Conplast SP420 is a chloride-free, workability-maintaining additive based on selected organic polymers.

It is supplied as a brown solution that instantly disperses in water.

Conplast SP420 disperses fine particles in the concrete mix, allowing the water content of the concrete to work more effectively. This increase in workability, cohesion and retardation minimises loss of workability.

Uses

It is used where retention of workability is required to overcome the rapid loss of workability caused by high temperatures or transport delays.

Advantages

  • Provides high workability in fresh concrete.
  • Maintains workability without the need for additional water, reducing time, placement and costs.
  • Improves cohesion, minimising segregation and improving surface finish.
  • Facilitates pumping, improving cohesion and reducing loss of workability.
  • Allows to decrease the water/cement ratio which increases durability, due to the decrease of permeability and shrinkage.
  • Chloride-free, it can be used with prestressed and reinforced concrete.

Standards

Conplast SP420 complies with UNE-EN 934-2:2010 Tables 3.1 and 3.2 as a high activity water-reducing / superplasticising admixture.

Typical dosage

The optimum dosage of Conplast SP420 that meets specific requirements will be determined by tests using the materials and conditions that will be encountered in practice.

This allows optimisation of the admixture dosage and mix design and also provides a comprehensive assessment of the concrete mix.

As a starting point for such tests, a dosage of between 0.35 and 1 litre/100 kg of cementitious material, including fly ash, slag and microsilica, can be used.

Properties

The following results were obtained at a temperature of 20°C:

  • Appearance: Dark brown liquid
  • Density: 1,193 ± 0,008 kg/l
  • pH: 8,0 ± 1,0
  • Water soluble chloride content (CI-): ≤ 0,10%.
  • Alkali content (Na2O equivalent): max. 6 % by mass
  • Primary function: Water reduction
  • Secondary function: Maintenance of workability

Mode of use

Mix design to maintain workability

The initial mixture should be pumped. For best results in maintaining workability, the initial mix should have a 2 cm cone. The delay and improved cohesion obtained with Conplast SP420 allows for increased workability retention characteristics.

In a properly designed flowable concrete, the better dispersion of cement particles and the more efficient use of mixing water will improve the cohesion of the mix. This improvement also helps to minimise exudation and segregation. After initial trials, it is advisable to make as few modifications to the mix design as possible to optimise the results.

Compatibility

Conplast SP420 is compatible with other Fosroc Euco admixtures used in the same concrete mix. If more than one admixture is used, they should be added to the concrete separately and not mixed together prior to being added. The resulting properties of concrete containing more than one admixture must be checked by prior testing.

Conplast SP420 is suitable for use with all cements complying with the RC-08 standard.

Dosing system

The correct quantity of Conplast SP420 should be measured using a suitable dosing system. Normally the admixture is added with the mixing water for best results. When a high workability concrete is required from a normal workability concrete, Conplast SP430 admixture can be added directly to the truck mixer. To ensure complete mixing of the admixture in the truck mixer, a mixing time of at least 2 minutes at high speed is required. Contact the Fosroc Euco Technical Department for advice on suitable equipment and installation.

Effects of overdosage

An overdosage of twice the maximum dosage indicated may cause delayed setting of the concrete as well as additional air entrapment.

Curing

The final characteristics of any structural concrete will depend on good curing practice. It is therefore very important to use a Fosroc Euco Concure curing membrane, water spray or wet burlap.

Clean-up and disposal

Spills of Conplast SP420 should be absorbed with sand or earth and transferred to suitable containers. Product residues should be flushed away with a large amount of water. Disposal of the product and packaging is the responsibility of the end user.

Limitations

All the characteristics of Conplast SP420, plasticiser, retarder and cohesion improver, contribute to the retention of workability. There may be cases where these properties are affected by the concrete components, especially local sands. In these cases, contact the Fosroc Euco Technical Department for advice on alternative products or combinations of these.

Storage

Conplast SP420 has a storage period of 12 months provided it is kept at a temperature between 2°C and 40°C.

Freezing point: -3 ºC approx.

Precautions

Safety and Hygiene

Conplast SP420 must not be swallowed or come into contact with skin and eyes. Wear protective gloves and goggles. Splashes on the skin should be washed off with water. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. If swallowed, seek immediate medical attention. Do not induce vomiting.

For further information, please refer to the Material Safety Data Sheet.

Fire

Conplast SP420 is water based and non-flammable.

Fosroc

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