Two groups of concrete mixtures, one without sodium sulfate and other with sodium sulfate, as an activator, were made with recycled powdered gypsum-wallboard for this investigation. Group 1 concrete mixtures were made using up to 20% of ASTM Class C fly ash and 20% powdered gypsum while Group 2 contained up to 60% of fly ash and 20% of powdered gypsum by mass. Relevant properties of concrete we...

This research is a part of a wide range investigation on the use of flue gas desulphurisation (FGD) in construction applications. It reports some results on the porosity and pore size distribution of cement paste containing varying amounts of fly ash-gypsum blends as partial replacement of cement. The cement was replaced with 25% of different blends of fly ash and gypsum. The gypsum content ran...

To address the problem of chloride ion transport in cement concrete marine environment, this study investigates effect metakaolin dosage on diffusion resistance mortar and its mechanism by testing binding capacity microstructure under coupling chlorine salt-sulfate-carbonation multiple factors. The results show that sulfate or carbonation reduces to some extent compared with single salt attack,...

Interest in using gypsum as a management tool to improve crop yields and soil and water quality has recently increased. Abundant supply and availability of flue gas desulfurization (FGD) gypsum, a by-product of scrubbing sulfur from combustion gases at coal-fired power plants, in major agricultural producing regions within the last two decades has attributed to this interest. Currently, publish...

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...

Building a 2,000-square-foot house leaves about a ton of gypsum wallboard waste from end cuts, window and door cutouts, and broken boards. In the United States, three million tons of gypsum wallboard waste is dumped in landfills each year. In addition to depleting space, microbial action can decompose gypsum to malodorous hydrogen sulfide gas, which at high enough exposures can cause irritation...

dS values in gypsum are used to evaluate the fate of sulfur in the hypersaline Lake Lisan, the late Pleistocene precursor of the Dead Sea (70–14 ka BP), and applied as a paleo-limnological tracer. The Ca-chloride Lake Lisan evolved through meromictic periods characterized by precipitation of authigenic aragonite and holomictic episodes characterized by enhanced gypsum precipitation. The lake de...

Abstract The article attempts to assess the possibility of using non-woven fabrics made waste fibers in cladding panels. For this purpose, woolen and polypropylene nonwovens were tested for mass per unit area, characteristic opening size, lengthwise crosswise elongation at maximum strength. Non-woven placed middle thickness cement gypsum boards subjected tests density, thermal conductivity coef...