Development of a New Betanaphthaline Sulfonate-Based Superplasticizer Especially Studied for Precast Application

Betanaphthalene sulfonate condensate (NS) and melamine sulfonate condensate (MS) polymers based superplasticizers have been extensively used in the Precast Industry. Continuous need for improving the performance of concrete has led to the development of products with a higher water reduction and thus higher early strength, typical of melamine based superplasticizers, but without the drawback of workability loss sometimes encountered with this kind of superplasticizers. The chemistry of the new product described in this article has been specifically designed to achieve high early and long term strength maintaining the workability typical of NS products at dosages in the range commonly used with melamines. The superior performance obtained with this new product makes it a good alternative to melamine based superplasticizers when used in precast applications. The paper reports the effect of the new B-naphthalene sulfonate based superplasticizer on water reduction, air content and compressive strength in concrete prepared with different types and brands of cement conforming to the new EN 197-1 standards. The results show that significant improvements in terms of water reduction and strength development can be achieved with this new NS based product, especially when used with CEM I type cements.