Polycarboxylate Superplasticizers to Ensure Workability Retention and Durability

摘要

The constant effort of the concrete industry to head towards sustainability implies the use of materials which may be characterized by a higher tendency to workability loss. However, workability retention has to be considered a key performance parameter to ensure a proper placing of concrete thus its homogeneity and durability in the structure. In the present paper, an investigation of the main reasons behind the workability loss are presented focusing on the chemical composition of cements and nature of the polycarboxylate (PCE) superplasticizers. On the basis of this interaction study new concrete admixture solutions are presented which can ensure a constant workability over time even under very demanding conditions such as high temperature and low soluble sulfates. These solutions are evaluated with many different set of materials confirming the general validity of the approach. Kinetics of adsorption of polycarboxylates, pore solution analyses and rheological data obtained with various cements allow interpreting the performance in concrete in the light of a new mechanism of action.