Did you know?

Sulfate attack on concrete is defined as the expansive reaction between penetrating sulfates and hardened binder phases. Expansion is generally attributed to the formation of ettringite and, at high sulfate concentrations, gypsum [1], [2]. Ettringite forms when penetrating sulfates react with AFm. However, recent investigations on the ...It was observed the formation of two main exothermic manifestations by isothermal calorimetric tests corresponding to gypsum and ettringite formation; however, an overlap of both processes was ...The Sr isotope data from the gypsum formation as a tectonic slice display the Late Triassic age of the Mediterranean belt (Gündoğan et al. 2008). The Neogene fill overlying unconformably the bedrock units is formed from ... (Turkey) and some recent sinkhole formation in its close vicinity (Kaklık Cave), 1st Int. WS on Role of …There may be several reasons why your iPhone is performing slowly, such as too many resource-hungry apps or not enough storage space. If you want to return your iPhone to its factory default settings, you can use your PC and iTunes to forma...DensGlass sheathing is a gold-colored fiberglass mat gypsum panel that raises the performance and adds long-lasting qualities to fire-rated and nonfire-rated building fabrications. The sheathings provide protection against moisture and mold...The observed tendency is for the anhydrite mass to change toward a spherical or ovoid shape. Dehydration of clusters of gypsum crystals or layers of crystalline (or detrital) gypsum would yield “chicken wire” anhydrite. The timing of the formation of the nodular anhydrite would depend on the P, T and activity of H 2 O of the pore fluids ...The goals of GYPWORLD are to (1) assess plant and lichen diversity associated with gypsum soils; (2) determine the origin of gypsophilic biotas worldwide; (3) understand …Gypsum is a very soft mineral that is easily identified by its hardness, cleavage, and solubility in water. Typically clear to white, gypsum may be colored reddish to brown or yellow if impurities are present. Most gypsum occurs in its massive form, as layers of rock that often intercalate layers of shale, limestone, or dolostone.Assuming that any expansion caused by gypsum formation is negligible, ettringite is the only expansive product. The volumetric change for each chemical reaction in Eqs. (2) , (3) , (4) is calculated by [ 17 , 18 ]: (22) Δ V i V i = M ettr − M i + a i M gyp M i + a i M gyp where M i , M ettr , and M gyp are respectively the molar volumes of ...Spread the loveMinerals are captivating treasures of the Earth, and among them, sulfate minerals shine with their unique properties and breathtaking beauty. As K …It has been found that gypsum and ettringite are two primary components subjected to chemical attack and the volume could expand by about 120% to 220% during the formation of ettringite and gypsum ...It was during this time that layers of gypsum were deposited on the seafloor. The rise and fall of the sea level millions of years ago started the process of making the gypsum sand that covers the monument today. Many factors, including the latest ice age, had an effect on the formation of this magnificent landscape.Nov 28, 2007 · The Opeche Formation consists predominantly of red mudstone. The upper 15 to 20 feet are a distinctively purplish red in contrast to the reddish brown of the rest of the formation. Two gypsum beds 5 to 7 feet thick occur—one near the middle, the other very near the base of the formation. Gypsum (CaSO4·2H2O) is the most common sulfate mineral on Earth and is also found on Mars. It is an evaporitic mineral that predominantly precipitates from brines. In addition to its precipitation in natural environments, gypsum also forms an undesired scale in many industrial processes that utilize or produce brines. Thus, better insights into gypsum formation can contribute to the ...A new study has suggested that the formation of gypsum starts as tiny crystals of a mineral called bassanite (CaSO 4·0.5H2O).[30] This process occurs via a ...1. Introduction. Textural observations, and compositional analyses of veins are important for understanding the vein formation processes. Veins filled with gypsum often consist of a median zone with fiber zones on both sides of it (Fig. 2 f), which is a distinctive feature of antitaxial fibrous veins (Bons et al., 2012).We conducted uniaxial deformation experiments on porous bassanite aggregates to study the effects of applied axial load σ a on deformation during the formation of gypsum. While hydration of bassanite involves a solid volume increase, gypsum exhibits significant creep compaction when in contact with water. These two processes occur simultaneously.The formation mechanism of authigenic gypsum is linked to the oxidation of authigenic pyrite and the evolution of the underlying methane seeps. Zhao et al. (2021) suggested that gypsum formation is likely associated with the downward migration of the sulfate–methane transition zone (SMTZ), which causes anaerobic pyrite oxidation at its ...Gypsum. Gypsum is a hydrated calcium sulfate with composition CaSO 4 ·2H 2 O. It commonly occurs as a chalky powder or occasionally as small crystals. In gypsum, the structure is layered, parallel to the b direction. Tetrahedral SO 4 anions are linked by Ca cations as chains parallel to c, which form as double sheets interlayered with sheets ... Mar 1, 2003 · This phenomenon was attributed to gypsum formation, which was confirmed by X-ray diffraction (XRD). In a study by Tian and Cohen [4], the effect of gypsum formation during sulfate attack on the resulting expansion of C 3 S paste and mortar prisms was investigated. The quantity of gypsum formed in various mixtures was compared by the relative ... Tian B., Cohen M.D.: Expansion of alite paste caused by gypsum formation during sulfate attack. J. Mater. Civil Eng. 12, 24–25 (2000) Article Google Scholar Tixier R., Mobasher B.: Modeling of damage in cement-based materials subjected to external sulfate attack. I: Formulation. J. Mater. Civil Eng. ASCE 15, 305–313 (2003)

Gypsification of anhydrite is associated with up to 63% swelling and dehydration of gypsum to form anhydrite results in a maximum volume reduction of 39% …Current conditions are still favorable for gypsum crystal formation and growth, with a water temperature at that depth of about 55 °C, Van Driessche says. There are even small ponds in the mine ...Gypsum formation mechanisms during external sulfate attack were studied on Portland cements of various C 3 A content exposed to low sulfate concentrations. Though ettringite is acknowledged as the main expansive phase during external sulfate attack, the simultaneous formation of gypsum can cause expansion of laboratory samples prepared with SR Portland cement.Name Gypsum Spring extended into Fort Hill quad, Greater Green River basin, reduced in stratigraphic rank from Gypsum Spring Formation to Gypsum Spring Member, and assigned to Twin Creek Limestone as its basal member. Gypsum Spring was formerly designated member A of Twin Creek by Imlay (1950).

Gypsum, common sulfate mineral of great commercial importance, composed of hydrated calcium sulfate. It occurs in extensive beds associated with other evaporite minerals, particularly in Permian and Triassic sedimentary formations; it is deposited from ocean brine, followed by anhydrite and halite.Oct 13, 2023 · Gypsum, common sulfate mineral of great commercial importance, composed of hydrated calcium sulfate. It occurs in extensive beds associated with other evaporite minerals, particularly in Permian and Triassic sedimentary formations; it is deposited from ocean brine, followed by anhydrite and halite. While the mechanism for gypsum formation during falling water levels was established e.g. 13,15, the corresponding time interval in between the two major gypsum units, and its climatic ...…

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs. The smallest video file formats are WMV, FLV, MPEG-4 and RealVideo. T. Possible cause: Nov 7, 2016 · The group reported that gypsum actually forms in a three-step proces.