Conplast® PA21(S)
Conplast PA21(S) is supplied as a dark brown liquid based on selected sugar reduced lignosulphonates in combination with compatible surface active agents.
Conplast PA21(S) is a chloride free admixture used to entraina controlled volume of air in a concrete mix whilst permitting,through its plasticising action, significant reduction in the free water content of the mix.
Conplast PA21(S) acts at the interface of the cement aggregate particles and mixing water to be distributed throughout the concrete. The entrained air bubbles are of the optimum diameter and spacing to give durability under freeze-thaw or salt attack conditions whilst enhancing lubrication during placing and produce impervious concrete.
Description
Uses
To Improve the quality and long term durability of concrete exposed to severe weathering conditions. It Increases the resistance of concrete to damage by sea water, frost and de-icing salts and also makes concrete structures less prone to cracking.
Reduces the permeability of low cement content concrete for mass pours such as dams and breakwaters.
Improves the cohesion and work ability of concrete where poorly graded or harsh sands and aggregates have to be used and minimises bleeding.
As an ideal pumping aid to maintain cohesiveness and to minimise segregation where concrete is placed mechanically.
Dosage
The optimum dosage is best determined by site trials with the actual concrete mix which enables the effect of work ability and air content to be measured. The rate of addition is generally within the range of 0.10 – 0.20 litres of Conplast PA21(S) per50 kg cement according to the air content required. A dosage of 0.15 litres for 50Kg cement is normally sufficient to obtain5% air entrainment.
