Addition Rates
Range: 500 ml–2000 ml per 100 kg cement (0.5% to 2.0% volume by weight of cement)
As with most products of this type, the magnitude of the effect obtained with DARACEM® 112 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 1.0%–1.2% 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 GCP.
Effects of Overdosing
The effects of overdosing DARACEM 112 are a function of the degree of overdose. When producing high workability concrete, overdosing 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 should be made to its plastic state in terms of consistency and cohesiveness, prior to a decision on the suitability of the concrete for the particular application in question.