The investigation aims to check the effect of variation of gypsum and water content on the engineering properties of expansive soil by different experiments, namely, mini compaction test, Atterberg limit's test, and unconfined compressive strength test along with microstructural analysis. The effect of gypsum (0%, 2%, 4%, 6%, 8%, and 10%), …Web
قرأ أكثر
Experimental results show that when the gypsum was added in the three kinds of cementitious system, water consumption of standard consistence decreased …Web
قرأ أكثر
Abstract Shrinkage cracks are easily occurred in mass concrete. To compensate the shrinkage, the sulphoaluminate expansive agent is usually used. …Web
قرأ أكثر
Abstract. Sulfate attack on Portland cement concrete is often said to arise from each of two major sulfate reactions: (1) The sulfate ions react with C{sub 3}A and its hydration products to form ettringite with an increase in volume that results in expansion and subsequent cracking of the concrete; (2) The sulfate ions react with calcium …Web
قرأ أكثر
This study used Grade 42.5 ordinary Portland cement containing 80% clinker, 5% gypsum, and 15% mineral additives. Its specific surface area was 330 m 2 /kg, ... linear expansion tests of the cement paste were conducted according to JC 313-2009 "The Test Method for the Linear Expansion of Cement Paste". The expansion-rate test was …Web
قرأ أكثر
only gypsum as a binder or overwhelmingly rely on gypsum as a binder relative to other binders. Distress from Grout expansion given adequate gypsum and portland cement content as well as exposure to moisture, internal volumetric expansion of post pocket grout can occur long after the grout's initial set. the expansion causesWeb
قرأ أكثر
Role of Gypsum in Cement. The main purpose of adding gypsum in the cement is to slow down the hydration process of cement once it is …Web
قرأ أكثر
Gypsum, from either nature or industrial by-products, can be a lower-cost and cleaner alternative binder to Portland cement used in construction projects, such as affordable housing in developing countries. Although various building products have successfully used gypsum as the binder, some drawbacks of this material have still …Web
قرأ أكثر
This is typical of cement and gypsum plaster hydration, etc., but also of a wide range of geochemical processes such as the weathering of rocks, hydrothermal mineral transformations, etc. One might even consider it to include the corrosion of metals in water, although of course that type of reaction also has a strong redox component …Web
قرأ أكثر
3.2 Unrestrained deformation. Figure 2 shows the influence of fly ash type and gypsum addition on early-age expansion behavior of OPC–CSA blends, respectively. The main difference between the two types of fly ashes (FFA and CFA) was reflected in the duration and magnitude of expansion. The expansion ceased earlier in …Web
قرأ أكثر
The results show that the best conditions for gypsum-bauxite grouting mortar are as follows: a water-to-binder ratio of 0.3, a mineral admixture content of similar to 15%, and a molar ratio K of 2.Web
قرأ أكثر
The results show that the best conditions for gypsum-bauxite grouting mortar are as follows: a water-to-binder ratio of 0.3, a mineral admixture content of ~15%, and a molar ratio K of 2. The ultimate …Web
قرأ أكثر
Ettringite is the mineral name for calcium sulfoaluminate (3CaO•Al 2 O 3 •3CaSO 4 •32H 2 ... expansion of deteriorating concrete. ... intergrinding the Type I cement with additional gypsum (SO 3 =3.14%) to increase the amount of available sulfate in the concrete. Concrete prisms made from these cements wereWeb
قرأ أكثر
Section snippets Materials. Natural river sand (0–4 mm) and commercial quartz sand (0.6–1.2 mm and 1.2–2.5 mm) with a specific gravity of 2.66 and 2.65, respectively were used as fine aggregates.The natural crushed gypsum with the SO 3 content of nearly 38% was used as a partial substitution of the natural river sand to raise …Web
قرأ أكثر
Gypsum, from either nature or industrial by-products, can be a lower-cost and cleaner alternative binder to Portland cement used in construction projects, such as …Web
قرأ أكثر
Gypsum is a versatile mineral widely used in various industries. It is primarily known for its use in the construction sector as a key component in drywall, plaster, and cement. Gypsum offers exceptional fire resistance, sound insulation, and moisture control properties. Additionally, it finds application in agriculture as a soil amendment to improve …Web
قرأ أكثر
In mass concrete, shrinkage resulting from temperature drop and drying leads to cracking, which can seriously affect the strength and durability of cement-based materials. Fortunately, expansion agents can deter or prevent these effects, especially MgO expansion agents (MEAs). In this study, the effects of four MEAs of different activity …Web
قرأ أكثر
The effect of gypsum additions on the physical performance of lime-stabilized kaolinite has been determined. Kaolinite containing different amounts of lime (i.e. 6 and 14 wt%) and gypsum (i.e. 2,4,6 and 8 wt%) was compacted into cylinders and moist cured at 30°C and r.h. for periods from 2 days up to 20 weeks.Web
قرأ أكثر
The expansion of MgO concrete is the result of the combined action of the expansion source and the environment in which it is located. Approximately 117% of molar solid volume increase relies on the hydration of MgO to Mg (OH) 2, but the expansion of MgO concrete is not equal to the expansion of MgO.Web
قرأ أكثر
When powdered plaster (CaSO 4 ·1/2H 2 O) is mixed with sufficient water to give a plastic paste, hydration occurs rapidly, forming a hardened mass of gypsum (CaSO 4 ·2H 2 O), usually with slight bulk expansion. The addition of certain compounds can greatly increase the expansion, which may lead to destructive pressures. Here I show that this …Web
قرأ أكثر
However, some scholars found that the formation of gypsum can also cause concrete expansion and cracking [14, 15]. As for the latter, the theories of solid volume increase, solid topological ...Web
قرأ أكثر
The results show that the main components of natural gypsum minerals were gypsum dihydrate (71%), dolomite (27%) and potassium chloride (2%). ... Cement hydration mechanisms through time – a review ... B1-15-2 and B1-16-2 with the specification of φ50 mm × H35 mm were selected to observe the change rule of axial expansion …Web
قرأ أكثر
This paper aims to study the effects of gypsum type and dosage on the rheological and strength properties of steel-slag cemented paste backfill (SSB-CPB) using fluorogypsum (FG), phosphogypsum (PG), and desulfurization gypsum (DG). Experimental results indicate that the yield stress and the viscosity of fresh SSB-CPB are the smallest …Web
قرأ أكثر
a significant expansion of the application areas of products based on them. Gypsumcement-pozzolan binder is a composition of gypsum binder, Portland cement and active mineral additives. Depending on the type and composition of each component, as well as the method of preparation, the physicochemical and mechanical properties of theWeb
قرأ أكثر
This results in the formation of expansive products such as gypsum and ettringite filling pores, which can lead to the expansion of cement-based materials and microcracks [6,7]. The associated leaching phenomenon in an acid solution leads mainly to the dissolution of portlandite (CH) and the decalcification of calcium silicate hydrates ( C …Web
قرأ أكثر
NEWARK, Del, March 21, 2023 (GLOBE NEWSWIRE) -- Gypsum sales are estimated to reach US$ 7.85 billion in 2023. By 2033, the market may register a 6.2% CAGR, reaching US$ 13.76 billion.Web
قرأ أكثر
Hydration characteristics and mechanical properties of calcium sulphoaluminate (CSA) cement with different contents of CaCO 3 and gypsum under NaCl solutions were studied, using the testing methods of isothermal calorimetry, X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), linear shrinkage, and compressive strength. …Web
قرأ أكثر
The article analyzes the influence of material composition of modified gypsum-alumina expanding cement with regard to mineral components ratio on its …Web
قرأ أكثر
Yu et al. [ 10] found that the changes in the microstructure of gypsum crystals in different concentrations of salt solution seriously affected its physical and mechanical properties, especially permeability, extreme strength, and deformation characteristics. Evju et al. [ 11] studied the growth and expansion of anhydrite in solution …Web
قرأ أكثر
For example, the red gypsum can be used for cement production as a binder [50], green concrete [51], calcium sulpho-aluminate cement [52], foamed concrete [53], cementitious materials [54], and ...Web
قرأ أكثر
Special Issue "Cement, Gypsum, and Lime Composites: Methods, Models, Kinetics, and Recent Advances" ... the use of L-GGBS combination was found to be effective in ameliorating sulphate-induced expansion and therefore encouraged in the stabilisation of subgrade and road-base materials with high sulphate contents. ... Mineral analyses …Web
قرأ أكثر
DOI: 10.1016/j.jobe.2023.106288 Corpus ID: 257529776; Hydration and mechanical properties of FGD gypsum-cement-mineral powder composites @article{Gou2023HydrationAM, title={Hydration and mechanical properties of FGD gypsum-cement-mineral powder composites}, author={Mifeng Gou and Mengke Zhao …Web
قرأ أكثر
The proportions of the mixtures are gypsum—70%, cement—15%, mineral additive—15%. The amount of superplasticizer 1% by weight of the mix. The amount of water was selected for each composition individually, taking into account the achievement of a …Web
قرأ أكثر