DARACEM® 148K

Advantages

• DARACEM 148K is especially suitable for producing high workability concrete that has excellent workability retention. In this application, minimum extensions of setting time and little loss in early age compressive strength are observed.
•  High workability flowing concrete can be obtained by incorporating DARACEM 148K into a concrete mix designed for a 50 mm slump. Normal pump mixes are recommended for this application.
•  DARACEM 148K can be used to effect high range water reductions, typically up to 30%, leading to considerable increases in compressive strength. Impermeability and durability are correspondingly improved.
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Typical Properties 

Addition Rates

Range: 500 ml–3000 ml per 100 kg cement (0.5%–3.0% [v/w] by weight of cement)

As with most products of this type, the magnitude of the effect obtained with DARACEM® 148K is governed by the quantity of product used and the specific nature of the concrete and its constituent materials.

It is therefore necessary to assess performance under site conditions using site materials to determine optimum dosage and effect on both plastic and hardened concrete properties, such as cohesiveness, workability retention, set characteristics, early rate of strength gain, ultimate compressive strength and shrinkage when these are of consequence. As a guide to these trials, an addition level of 1.2%–1.4% DARACEM 148K volume/weight of cement is recommended.

Addition rates outside the recommended dosage range may be used for special concrete applications. This may be the situation when Silica Fume or Blast Furnace Slag Cement is used. In such circumstances it is important to conduct preliminary trials on the actual mix constituents to assess the effect on the properties of the concrete, at the dosage level specified.

For advice and assistance with your trials we would recommend that you consult Grace.

Effects of Overdosing

The effects of overdosing DARACEM 148K are a function of the degree of overdose.

When producing high workability concrete, over-dosing will increase the level of workability and may induce the onset of segregation.

Depending on the extent of the overdose, an increase in the setting time may also occur, especially in low temperatures and/or when employing sulphate resisting cement or cement replacement materials.

In any situation where overdosing is suspected, a careful inspection of the concrete in its plastic state should be conducted. Particular attention should be paid to consistency and cohesiveness, prior to a decision on the suitability of the concrete for the particular application in question.