Optimum 380 is a high-performance polycarboxylate-based super plasticizer that helps to improve workability and produce self-consolidating concrete (SCC). This premium admixture can help extend slump flow life, impart extreme workability without segregation, reduce water-to-cement ratios and deliver early strength. It is available in 1-quart, 1-gallon and 5-gallon containers.
When a concrete mix contains superplasticizer, the hydration of cement increases rapidly, which results in an earlier strength gain. Moreover, this effect lasts longer for concrete containing the superplasticizer than for a similar mix containing no such additive. Consequently, the concrete with the superplasticizer has an extended slump life and is easier to place by hand or pump.
The optimum dosage of the superplasticizer in any given concrete mix depends on the actual cement and its w/c ratio. Generally, superplasticizer is effective at low dosages and becomes less effective as the cement w/c decreases. However, it is also important to select a superplasticizer that is compatible with the actual cement.
A rheological test can be performed to determine the optimum dosage of the superplasticizer. The test involves plotting the marsh cone time versus the superplasticizer dosage. The point at which the marsh cone time is a minimum is the optimum superplasticizer dosage for the cement and w/c ratio.
Once the optimum dosage is determined, it should be added to the concrete mixture as per the manufacturer’s recommendations. The addition rate varies according to the type of mixture, aggregate gradations and form geometry, but it typically ranges from 4 to 16 fl oz/100 lbs of cement. It is recommended that the admixture be thoroughly mixed prior to use.