Micro-con Air Concrete Admixture

Micro-con AIR is a chloride free air entraining admixture based on neutralized Vinson resin. Micro-con AIR acts at the interface between the mixing water and cement/aggregate particles to produce microscopic air bubbles, which are evenly distributed throughout the concrete. The entrained air enhances durability by providingprotection. Against the rapid temperature changes found in freezing and thawing conditions and with the use of de-icing salts.

Mycrocon AIR forms the solid-water interface where directive forces exist in the cement surface, the polar groups become bound to the solid with the nonpolar groups oriented toward the water, making the cement surface hydrophobic so that air can displace water and remain attached to the solid particles as bubbles.

Where to use:

➢ To produce air entrained concrete that increased durability and resistance to damage by frost and deicing salts. It includes concrete roads and bridge decks, airport runways and taxiways and other extensive areas of concrete exposed to potential frost damage.

➢ To improve cohesion and workability of concrete mixes where poorly graded aggregates must be used and bleeding, segregation or sand runs occur.

Features of Mycrocon AIR:

➢ Air entrainment increases the resistance of concrete to attack by frost and de-icing salts, reducing problems of surface scaling and concrete failure.

➢ Entrained air bubbles assist in the formation of a stable cohesive mix, reducing segregation and bleeding.

➢ Air entrainment improves workability and helps produce a dense, uniform, close textured surface free from gravel nests and sand runs, so further enhancing durability.

Method of Application

The optimum dosage of MYCROCON AIR to meet specific requirements must always be determined by trials using the materials and conditions that will be experienced in use. This allows the optimisation of admixture dosage and mix design and provides a complete assessment of the concrete mix.

As a starting point for trials a dosage of 0.08 litres/100kg of cement will typically give an air content of 5% ± 1.5% in a medium workability concrete of 300- 350 kg/m3 cementitious content. Where cement replacement materials are used, they should be included in the cementitious content for purposes of calculating admixture dosage.

Precautions & Limitations

➢ Do not add Mycroblock 100 directly to dry cement & aggregate mix.

➢ Maintain water-cement ratio as low as possible.

➢ Do not increase the dosage of Mycroblock 100 than the recommendation.

Compatibility:

Mycrocon AIR can be used with all types of Portland cements and is generally compatible with other admixtures. It is recommended that all admixtures be added to concrete separately.

Curing:

As with all structural concrete, good curing practice should be maintained.

Overdosing:

An overdose of double the recommended measure of Mycrocon AIR will increase workability and air content and can result in slight set retardation of the concrete. The

ultimate strength of the concrete should not be impaired if advantage is taken of the water reduction and the concrete is adequately cured.