In this study, the effects of titanium dioxide (TiO₂) nanoparticles on the sulfate attack resistance of ordinary Portland cement (OPC) and slag-blended mortars were investigated. OPC and slag-blended mortars (OPC:Slag = 50:50) were made with water to binder ratio of 0.4 and a binder to sand ratio of 1:3. TiO₂ was added as an admixture as 0%, 3%, 6%, 9% and 12% of the binder weight. Mortar speci...

With the rapid development of economic, gypsum is widely used in casting and other industry areas. In this paper, the result is obtained that the performance of plaster mold is better when gypsum-water ratio is 0.5. If the composition of gypsum slurry mixture ( -hemihydrate, mullite powder, zirconium powder, reinforcing fibers) is mullite powder: zircon flour: enhancing fiber = 1:0.25:0.2:0.02-...

The sorption of dissolved inorganic pollutants into the structure of minerals is an important process that controls the mobility and fate of these pollutants in the Earth’s crust. It also modifies the surface structure and composition of the host mineral, affecting its crystallization kinetics. Here, we investigate the effect of hexavalent chromium, Cr(VI), on the nucleation and growth of gypsu...

Synchrotron-based smalland wide-angle X-ray scattering (SAXS/WAXS) was used to examine in situ the precipitation of gypsum (CaSO4·2H2O) from solution. We determined the role of (I) supersaturation, (II) temperature and (III) additives (Mg2+ and citric acid) on the precipitation mechanism and rate of gypsum. Detailed analysis of the SAXS data showed that for all tested supersaturations and tempe...

ABSTRACT: Extreme swelling pressures (in excess of 5 MPa) were measured against the invert of a tunnel excavated by drill and blast method in a hard claystone containing variable proportions of anhydrite and gypsum dispersed in the clay matrix. When the invert was not present, floor heave reached displacements in excess of 60 cm in some cross sections. Displacements and pressures developed at a...

In order to determine the feasibility of manufacturing wood-gypsum and wood-gypsum-cement particleboards, the hydration reactions of four Eastern Canadian wood species with gypsum and Portland cement were studied. The compatibility of hot water extracted and raw wood particles with both gypsum and a gypsum-Portland cement mixture were determined for jack pine, balsam fi r, aspen and white birch...

The sustainability of irrigated agriculture in many arid and semiarid areas of the world is at risk because of a combination of several interrelated factors, including lack of fresh water, lack of drainage, the presence of high water tables, and salinization of soil and groundwater resources. Nowhere in the United States are these issues more apparent than in the San Joaquin Valley of Californi...

A lack of well preserved paleoclimate indicators coupled with the abundance of gypsic soils in arid and semi-arid regions has stimulated research on using dO and dD isotopic analysis of the hydration water of gypsum to interpret paleoclimate. This study stresses the importance of establishing a pedogenic origin for gypsum crystals prior to isotopic analysis and evaluates the dominant processes ...

This research determines which of the phenomena that appear during cavitation are responsible for the erosion of some brittle water soluble materials, such as gypsum and alum, when exposed to a high intensity ultrasound field over the cavitation level. The observation that gypsum suffers no erosion under the effect of an ultrasound field when the material is irradiated in a saturated solution o...

Water vapour transport properties of gypsum block are studied in dependence on relative humidity using inverse analysis based on genetic algorithm. The computational inverse analysis is performed for the relative humidity profiles measured along the longitudinal axis of a rod sample. Within the performed transient experiment, the studied sample is exposed to two environments with different rela...