Screed accelerators are aggregates that are added to conventional cement screeds and enable faster setting and thus faster readiness for covering. Rapid screeds are ready-made prefabricated screeds with a correspondingly shortened readiness for covering.
The background to this is the fact that conventional cement screeds do not consume the entire amount of water required for a workable consistency of the screed through the setting/hydration process. The excess water causes long drying times and late readiness for covering. This excess water is permanently bound firmly (crystalline) by screed accelerators and rapid screeds, which enables much faster paving, in extreme cases within a few hours.
Taking into account the manufacturer's specifications and the dosage of the screed accelerator or the selection of the rapid screed, the time of readiness for covering can be controlled in a targeted manner. Nevertheless, the actual readiness for covering must be checked by CM measurements, the same residual moisture values do not apply as for conventional screeds, but the manufacturer provides information on this, e.g. in the Technical Data Sheet, at which CM value the readiness for covering is reached depending on the intended topsoil. Since the CM measurement is not carried out by the screed layer but by the floor layer, he must be informed about the product used and its properties, e.g. by handing out the Technical Data Sheet.
The disadvantage of the fast systems is the significantly higher costs depending on the acceleration. This should therefore only be interpreted according to actual needs. The processing specifications for the product used must be observed and adhered to. Before application, it must also be checked whether the intended floor covering allows installation on screed accelerators/rapid screeds.
Screed accelerators and the screeds and rapid screeds produced with them are also non-regulated building products/construction types within the meaning of the building rules list and therefore require a general building inspection test certificate (abP) or a general building authority approval (abZ) as proof of usability.
Source: bauwion
