Papers by Author: Ji Xiu Zhang

Abstract: The α-type high-strength gypsum with its superior strength and performance is widely used in precision casting, ceramic molds, arts and crafts as well as plaster and GRG self-leveling and other industries that have higher demands to the dimensional stability of the products. Solidification rate of expansion is an important characterized parameters of gypsum volume stability, and also an important indicator of α-High-Strength gypsum plaster. The common adjustment method of Solidification rate of expansion is to add additives to change the gypsum hydration process. But the influences of different types of additives on setting expansion have not been studied yet, therefore, this paper studied on the influences of citric acid, tartaric acid and sodium pyrophosphate on the solidification rate of expansion of the α-High-Strength gypsum plaster. The results indicate that the gypsum expansion rate was decreased with the increase of gypsum set retarder, the expansion rate was firstly increased and then decreased when the citric acid and sodium pyrophosphate increased; however, when the tartaric acid increased, the expansion gradually decreased, and the tartaric acid and the expansion of the gypsum by and large are in an inverse proportion.

Abstract: This experimental research was to investigate the chloride penetration and consolidation behavior of OPC and coal gangue added cement. By comparing the results of two kinds of cement, results showed that the chloride consolidation of gangue added cement is higher than OPC. The chloride consolidation increased with more gangue added. The coal gangue is helpful to impede the chloride ingress until the added content reach 30%. The more gangue content decreased the fluid of mortar. And this increased the porosity of harden pastes. Furthermore the corrosion behavior of steel bar in OPC and G30 samples were conducted. Corrosion potential of gangue added cement moved positively comparing with OPC. These indicated that the propriety gangue content was helpful to steel bar protection.