Influence of the gypsum dehydration temperature and alkali additives on the properties of anhydrite cement

Abstract

While dehydrating gypsum with additives at the temperatures of 800°C and 900°C the influence of alkali additives on both the crystalline structure of anhydrite and properties of anhydrite binder was investigated. The industrial and household wastes including other lowcost materials were used as additives. Having heated them with gypsum the anhydrite with alkali activation properties was obtained. The properties of such substances were evaluated using the methods of chemical, diffractive X-ray scanning and scanning electron microscopy (SEM) analyses. Some additives, e.g. 5 % ground glass waste, were found to increase crystal agglomerate formation of anhydrite binder, accelerate the hydration process of anhydrite and double the compressive strength of hydrated samples compared to samples without additives

Influence of the setting activators on the physical mechanical properties of phosphoanhydrite

“…Activation of anhydrite cement can be increased upon grinding it with impurities [3,10,11] or dissolving activators in water during specimen formation [4,5,12,13]. Different researches analysed the impact of the following hardening activators: Na 2 SO 4 , K 2 SO 4 , (NH 4 ) 2 SO 4 , FeSO 4 , CaCl 2 and K 2 Cr 2 O 7 [3][4][5][6][12][13][14][15][16].…”