1 COMPATIBILITY ISSUES OF NSF-PCE SUPERPLASTICIZERS WITH SEVERAL LOTS OF DIFFERENT CEMENT TYPES (LONG-TERM RESULTS)

Synopsis: This paper focuses on the compatibility issue between cement and chemical admixtures. Different kind of chemical admixtures were considered belonging to naphthalene (NSF) and polycarboxylate-based families. Five lots of six different cements widely spread in Italy were considered. Mortars and concretes were manufactured by varying superplasticizer dosage to achieve fixed workability at the end of mixing. Flow retention up to sixty minutes and tendency to entrap air in the mortars and concrete were measured to evaluate performances in terms of water reduction and workability loss of each chemical admixture. Compressive strength at 1, 7 and 28 days was also considered. The rheological and mechanical behaviour of manufactured concretes showed good agreement with results collected on mortars