INVESTIGATING THE RELATIONSHIP BETWEEN TH E STIFFENING AND THE ELECTRICAL-CONDUCTIVITY OF GYPSUM PLASTER MIXTURES WITH ADDITIVES

The action of additives on the progress of hydration in gypsum plaster mixtures can be described with the aid of the hydration influencing f actor. The general relationship t = n . hbf - m was found to exist bet ween this parameter obtained from conductivity measurements and the st iffening behaviour. The constants n and m are characteristic of the gy psum binder used and also differ for the accelerating and retarding ad ditives. For the gypsum binder under observation it has been shown tha t the stiffening times can be calculated for the retarded gypsum plast er mixtures and estimated for the accelerated ones.