Addition Rates
Range:
0.4% - 3.0% volume by weight of cement The performance of DARACEM SP4 is best assessed after preliminary trials in the laboratory or on site, using the actual mix constituents under consideration, to determine the optimum dosage and effect on concrete properties such as compressive strength, setting times, workability retention, etc. when these are of consequence
As a guide to these trials, an addition rate of 400ml – 3000ml DARACEM SP4 per 100kg cement is recommended.
For silica fume concrete mixes, addition rates greater than 1500ml per 100kg cement are recommended, but lower dosage levels may be feasible following trial mixes and depending upon w/c ratios.
Effects of Overdosing
Overdosing of DARACEM SP4 will generally produce an increase in workability and a slight increase in air entrainment, which will be accompanied by a delay in the concrete setting time.
However, provided the overdosed concrete is cured properly, the ultimate strength will generally be higher than normal concrete.
The effects of overdosing with respect to set retardation are increased when sulphate resisting cement (Type V) is used in the mix design.
Dispensing
It is preferable that liquid admixtures for concrete be introduced into a mixer by means of automatic dispensing equipment details, which are available upon request.