The dissolution pattern of alpha and beta activity from gypsum sample when leached with 50,100,150ml of rain water,at different time intervals was determined. The dissolution rate increases if the solid to liquid ratio(gypsum to rain water volume) increases.It also increases with time , even though faster in the initial stages, slower in the subsequent stages. The dissolution rates are also inf...

The effects of a number of design parameters have been investigated including the types of cavity insulation, resilient channels, gypsum board thickness, the number of gypsum board layers, stud arrangements, and type of framing. The results have shown that the main factors that affected the performance of stud wall assemblies were the type of insulation and the number of gypsum board layers. In...

Paris (CaS04)2H20. Excessive heat convey it into anhydrous calcium sulphate CaB^< which takes up water very slowly and does D?. harden and set. 2CaS04.2H20 = (CaSW 2H20+3H20. (CaS04)2H20 = 2CaS 04H2U, Commercial plaster of Paris is manufacture from impure gypsum and therefore contains tn impurities present in the gypsum such as alum10^ iron, silicates, carbonates, lime, etc., which be recognize...

Sulfate attack is a series of physico-chemical reactions between hardened cement paste and sulfate ions. Sulfate ion penetration into the hydrated cement results in the formation of voluminous and deleterious phases such as gypsum and ettringite which are believed to cause deterioration and expansion of concrete. Concrete deterioration due to sulfate attack depends on many parameters, however, ...

iii DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disc...

Gypseous soil, as is well known, includes a specific quantity of gypsum. Gypsum water-soluble salt with solubility (2.2-2.6) gram/liter in distilled - water. As result, the presence gypsum poses challenge when building structures on this since dissolves exposed to water, producing gaps between soil particles and so causing collapse. This study examines behavior shallow foundation rested gypseou...

The filling mining method is important in realizing the green of mineral resources. Aiming at problems land resource occupation, environmental pollution, and rational utilization coal-based solid wastes such as coal gangue, fly ash, desulfurization gypsum, a new paste material was developed with gypsum raw materials. microstructure materials analyzed by XRD SEM. Combined Box-Behnken experimenta...

Mineralogical processes taking place close to equilibrium, or with very slow kinetics, are difficult to quantify precisely. The determination of ultraslow dissolution/precipitation rates would reveal characteristic timing associated with these processes that are important at geological scale. We have designed an advanced high-resolution white-beam phase-shift interferometry microscope to measur...

Human arsenic exposure from rice consumption is a global concern. Due to the vast areas of naturally contaminated soils in rice-producing regions, the only possibility for reducing hazardous exposure is to prevent As uptake and translocation to rice grain. Sulfur inhibits As mobility both in soil and plant, indicating that soil S content may be a primary factor controlling As uptake; indeed, gy...