The threat of P transport from land applied manure has resulted in water quality concerns. Research was conducted to evaluate gypsum as a soil amendment applied to grass buffer strips for reducing soluble P in surface runoff. A simulated concentrated flow was created in an established tall fescue (Festuca arundinacea Schreb.) pasture. Poultry litter (PL) was applied at a rate of 250 kg N ha(-1)...

The dehydration of gypsum CaSO4.2H20 has been studied, at negligible water vapour pressure, by in situ infrared (IR) spectroscopy and by thermogravimetry to determine whether intermediate phases (CaSO4.nH20) exist, other than the hemihydrate with n=0.5, and also to compare the mechanism of the dehydration process when measured by two techniques with very different correlation lengths. Thermogra...

application of cellulosic fibers and minerals of deinked waste paper sludge has a great impression on utilization and characteristics of final product. this study was designed to produce use gypsum-fiber board from the dip sludge. the gypsum: sludge ratio was considered as 100:0, 90:10, 80:20, 70:30 and 60:40. two types of gypsum boards were prepared with fixed 12 mm thickness and cold pressing...

Steel embedded in cement mortar in the uniaxial compressive stress direction was found to decrease by 80% the compressive longitudinal strain at a given stress and increase by 300% the tensile transverse strain at a given longitudinal strain. The former effect is due to longitudinal confinement of mortar by steel. The latter is due to debonding at the steel-mortar interface. © 1999 Elsevier Sci...

Based on the engineering background of water dissolving mining for hydrocarbon storage in multi-laminated salt stratum, the mixed mode fracture toughness and fracture trajectory of gypsum interlayers soaked in half-saturated brine at various temperatures (20°C, 50°C and 80°C) were studied by using CSNBD (centrally straight-notched Brazilian disc) specimens with required inclination angles (0°, ...

Wheat straw based composting generates a selective substrate for mushroom production. The first phase of this process requires 5 days, and a reduction in time is wished. Here, we aim at understanding the effect of gypsum on the duration of the first phase and the mechanism behind it. Hereto, the regular process with gypsum addition and the same process without gypsum were studied during a 5-day...

Blended cements based on the partial replacement of Portland cement clinker (PC) by wastes have been the subject of many investigations in recent years. The use of the replacement materials offer cost reduction, energy savings, arguably superior products, and fewer hazards in the environment. These materials participate in the hydraulic reactions, contributing significantly to the composition a...

The mechanism of corrosion of reinforcing steel in concrete is discussed based on electrochemical and electron microscopy observations. The importance of calcium hydroxide precipitation on the steel surf ace in the steel/mortar interface is evaluated by placing filter paper around reinforcing steel bar specimens prior to casting in mortar, thus preventing direct contact between steel and mortar...