Hydration of cement in the presence of asbestos was traced by means of hydration heat and adsorption capabilities of asbestos. Asbestos and cement samples were prepared in laboratory in proportions similar to those found in industrial materials. Asbestos was chrysotile by its mineralogical properties, of a short-fibered sort. Hydration heat was determined calorimetrically by means of spherical thermos flasks ; adsorption capability of asbestos fibers was determined relative to Ca(OH)_2. The hydration process was represented by integral and differential curves, wich indicated that hydration heat development was intensified in the presence of asbestos. The results obtained for adsorption have showed that asbestos surface is active, with 10^18 active sites per cm^2. The isotherms obtained are multistep ones and indicate the formation of two layers of adsorbate. Adsorption capabilities of asbestos intensify cement hydration.

Kemijsko inženjerstvo