Batimix AWA 540

Holderchem

Anti-washout admixture for underwater concrete

Description

BATIMIX AWA 540 is a liquid admixture that increases resistance to washout of cement and fines during casting of underwater concrete.

Main Purpose

BATIMIX AWA 540 is particularly recommended for underwater concreting where conventional concrete would result in a high percentage of material loss due to washout. It eliminates the need for expensive de-watering systems during underwater construction.

BATIMIX AWA 540 is based on high-grade water-soluble polymers, characterized by their long-chains of complex forms, which intertwine and develop attractive forces through their hydrogen bonds and polymer entanglements.

BATIMIX AWA 540 is used in all types of underwater construction with or without steel reinforcements.

Features

Concrete prepared with BATIMIX AWA 540 is characterized by the following:

In the plastic state:

  • Greatly reduced-level of bleeding and segregation
  • Improved washout resistance in fresh and sea-water
  • Increased cohesiveness with fewer risks of water dilution
  • Improved stability of fresh concrete during casting and thereafter
  • Thixotropic action, providing enhanced homogeneity

In the hardened state:

  • At normal dosages, no detrimental effect on setting time
  • Improved durability and better surface quality

Properties

  • Appearance: brown liquid
  • Specific gravity: around 1.01 at 23 ºC
  • Chloride content: nil
  • Alkali content: typically less than 1% as Na₂O
  • Air entrainment: less than 1% increase at normal dosages

Health and Safety

BATIMIX AWA 540 is not considered a hazardous product. However, it should not be swallowed or allowed to come into contact with skin and eyes. Suitable gloves and goggles should be worn. For additional information, kindly refer to the product’s Material Safety Data Sheet.

Compliance with Standards

BATIMIX AWA 540 is developed to comply with the requirements of BS 8443:2005.

Dosage Rates

BATIMIX AWA 540 is generally used in conjunction with a superplasticizer to secure the required concrete workability without additional water. Its optimum dosage and its effect on the underwater concrete fresh properties should always be determined by trials using the actual mix composition with site materials under field conditions. This allows better optimization of admixture dosage and provides complete assessment of mix design properties. As a guide to such trials, the addition rates shall vary from 0.5% to 1.4% of the cementitious materials.

Effect of Overdosing

Concrete mixtures overdosed with BATIMIX AWA 540 will result in a highly sticky and viscous material requiring higher dosages of superplasticizer to ensure the required workability. This, in its turn, will significantly retard setting and decrease strength development especially after 24 hours. Provided that adequate curing is implemented, the ultimate strength will not be impaired by such setting retardations.

Compatibility

BATIMIX AWA 540 is compatible with all other Batimix admixtures incorporated in the same concrete. It should not be pre-mixed with other admixture as this may alter its performance. During batching, the admixtures should be dispensed and added separately to the concrete mix. The performance of various admixtures on the fresh and hardened concrete properties should be assessed using trial tests.

BATIMIX AWA 540 is compatible with all types of Portland cement and replacement materials such as silica fume, fly ash, and blast furnace slag.

Dispensing

Accurate and reliable automatic dispensing systems should be used to introduce the correct quantity of BATIMIX AWA 540 in the concrete mixer. This product should not be directly added on the dry cementitious particles. It should rather be introduced towards the end of mixing, i.e. after incorporating all of the mixing water and other chemical admixtures.

Typical batching sequence that may be used when producing flowable underwater concrete with BATIMIX AWA 540 is as follows: • air entraining admixture (optional) • set-modifying admixture (optional) • high-range water reducer • BATIMIX AWA 540

Technical Support

Holderchem provides, upon request, complete technical support and on-site assistance to enable correct and effective use of its products.

Storage

BATIMIX AWA 540 has a minimum shelf life of 12 months if kept unopened and stored at temperatures ranging from 2 to 50 ºC.

Packages

  • 1 t IBC
  • 200 kg metallic drum
  • 20 kg metallic pail
  • 4 kg metallic pail
TS 5551Issue Date: 04-12-2020

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