Trade Journals for the Concrete Industry

It is generally well known that superplasticisers (SP), in particular high-performance polycarboxylate ethers (PCEs), cause retardation in cement hydration. This decreases productivity in all sectors of the concrete construction industry but has an especially detrimental effect on the precast sector. In the following report, it will be shown how two-stage mixing procedures can be utilised to achieve improved flowability for mortars with a reduced SP dosage and lower w/c-value as well as to attain more rapid strength development. Mixing processes are one of the most important procedural steps in producing construction materials. Little has been known, however, up to the present time of their action on the properties of concrete both in its fresh and hardened state.