The first applications of gypsum in construction date from the Neolithic period, e.g. in Çatal Huyuk, Turkey, circa 6000 ac [].The oldest remaining testimony from the use of gypsum by the Egyptians is the plaster of the pyramids (4000 to 2000 ac), even though in those times constructions were made of stone laid over stone without any kind of mortar [].
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The results showed that the water to gypsum ratio increased with increasing the fineness of the gypsum to (0.75%) and the setting time to the maximum allowed according to the Iraqi standard (25 ...
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Fineness of cement affects properties like gypsum requirement, workability of fresh concrete & long term behavior of structure. Coarse cement particles settle down in concrete which causes bleeding. Approximately 95% …
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Test methods are detailed for the following: precautions for physical tests, reagents and materials, free water, fineness, normal consistency of gypsum plaster and gypsum concrete, setting time, setting time (temperature rise method), compressive strength, and density.
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The fineness of the gypsum reduced the dissolution time of the gypsum and increased the time for secondary ettringite formation (from the sulphate absorbed by the C-S-H). This way, the fineness of the gypsum altered the hydration kinetics of the cementitious paste. 3 100 90 80 70 60 50 40 30 20 10 0 gypsum 2 C3A 1 Alite 3.3.
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IS : 2542 (Part I/Sec 1 to 12) - 1978 2 (Continued from page 1)Members Representing SHRI D. MOHTA Raj Plasters Ltd, Bikaner SHRI L. RAMIAH Gypsum Industries Pvt Ltd, Tiruchirapalli DR A. V. R. RAO National Buildings Organization, New Delhi SHRI G. T. BHIDE (Alternate) SHRI M. V. S. RAO Engineer-in-Chief's Branch, Army Headquarters SHRI V. K. RAZDAN (Alternate) …
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Influence of the heating temperature and fineness on the hydration and mechanical property of recycled gypsum plaster was investigated to find the suitable heating temperature and fineness.
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7. Fineness 7.1 SigniÞcance and UseÑ This test method covers a proce-dure for determining the Þneness of gypsum and gypsum plasters and is used to determine …
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Global Gypsum (GG): Can you outline Gebr. Pfeiff er's background in the gypsum sector? Patrick Heyd (PH): Gebr. Pfeiff er has a long history ... Fineness = <1% R 0.200mm Power = 600kW Crystal water (feed) = 20.0% Crystal water (prod) = 5.5% Above: MPS 225 B grinding-drying mill for natural and
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For this purpose, three types of cement having different Blaine fineness (2600, 3400 and 4100 g/cm 2) were produced from the same clinker and gypsum. In addition, cement having a fineness value of ...
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Fineness 7.1 Significance and Use—This test method covers a procedure for determining the fineness of gypsum and gypsum plasters and is used to determine compliance with gypsum and gypsum plaster specifications.
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For bulk density, the minimum limit determined by the Brazilian standard ABNT NBR 13207:1994 is 700 kg m − ³. However, recycled gypsum has lower bulk density than commercial gypsum, since the sequence of hydration and calcination of gypsum tends to reduce the size of the molecules and increase the volume of voids (Carvalho et al., 2008, Pinheiro …
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Scope. 1.1 These test methods cover the physical testing of gypsum, gypsum plasters, and gypsum concrete. 1.2 The test methods appear in the following sections:
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Four different fineness levels were considered: standard cement (commonly available cement in the market), and cements passing through sieves of 325, 425, and 500 mesh. These were …
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As a result, its preparation from local raw gypsum (CaSO4. 2H2O), which is the most predominant naturally occurring sulfate mineral (Van Drissche et al., 2019 in Abdula et al., 2022 and abundant ...
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Question: What is the purpose of adding gypsum to cement during the manufacturing process?a) To increase the fineness of cement particlesb) To decrease the setting time of cementc) To improve the strength of cementd) To control the rate of hydration and prevent flash setting
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The objective is to reduce the ore in size through various closely controlled stages to that degree of fineness which gives an economic liberation of valuable mineral, but which avoids as much as possible the production of sliming fractions. A different philosophy applies to the crushing and grinding of Gypsum.
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After the gypsum has attained rigidity then they restrain the motion of the free ends preventing expansion. The magnitude of expansion mainly depends on the fineness of gypsum powder, the effect of water-gypsum ratio, the addition of retarders or accelerators, the added sand/lime paste. Effect of Fineness of Gypsum Powder:
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Gypsum is the crystalline chemical compound CaSO4·2H2O. A close chemical relation - and frequently occurring with Gypsum - is Anhydrite which is CaSO4. Gypsun ... In the grinding stage the fineness most generally is turned out at 90-93% minus 100 mesh with a 325 mesh range of 30 to 50%. There are, of course variations depending upon desired ...
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Cement fineness plays a crucial role in defining the factors that influence strength and quality. Cement fineness influences and controls various cement properties. This includes the rate of evolution of heat, the rate of gain of strength, and the rate of hydration. The common value of the fineness of the cement is around 300–400 cm2/kg.
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Gypsum Physical Properties. Hardness: Gypsum is a relatively soft mineral on the Mohs scale of mineral hardness, with a hardness rating of 2. This means that it can be easily …
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Gypsum: Added to regulate the setting time of the cement. Step 2: Crushing and Grinding. The raw materials, including clinker, pozzolanic materials, and gypsum, are crushed into fine powder in ball mills or tube mills. …
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Fineness 7 Normal Consistency of Gypsum Plaster 8 Normal Consistency of Gypsum Concrete 9 Setting Time 10 Setting Time (Temperature Rise Method) 11 Compressive Strength 12 Density 13 1.3 The values regarded as the standard are either in inch-pound units or SI (metric). The values stated first shall be
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Two types of PCC with high fineness 298m²/kg and PCC with 233m²/kg low fineness were used and the lime fineness and gypsum were 587.6 m²/kg and 385.11m²/kg, respectively, so it's sure the addition of gypsum and lime will increase the surface area of the mixes, as shown in Figure (4). The flow test as in Table (5) shows when increase lime ...
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To maximize early compressive strength and apply the findings to construction sites, the research team added gypsum to OPC clinker, increasing SO 3 to 3.1% and improving fineness by 111.8% (400 cm 2 /g on 3400 cm 2 /g). In this study, the new HSPC was evaluated against OPC by setting time and early compressive strength according to cement fineness …
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1.1 These test methods cover the physical testing of gypsum, gypsum plasters, and gypsum concrete. 1.2 The test methods appear in the following sections: Precautions for Physical Tests 4 Reagents and Materials 5 Free Water 6 Fineness 7 Normal Consistency of Gypsum Plaster 8 Normal Consistency of Gypsum Concrete 9 Setting Time 10
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Fineness of cement: it's an indicator to the size of cement particles. Cement is considered fine if the percentage of weight retained on sieve #170 is less than 10%. Fineness of gypsum: it's an indicator to the size of gypsum particles. Gypsum is considered fine if the percentage of weight passing sieve #14 is and the percentage of weight passing sieve #100 is more than 75%.
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Gypsum (C 0 G 100) is the softest material among the studied; however, it has a sharp feed PSD and low size, which can increase the resistance to grinding. This is seen by gypsum's initial fineness (n = 1.42), which has a narrower PSD than limestone (n = 0.70). The uniformities of the materials were very similar after being ground by the ball ...
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The two carbonate powders have similar fineness, and both show a slightly finer particle size than the CSA clinker. Table 1. Chemical and mineralogical composition of the used materials. Empty Cell: CSA clinker ... The increased gypsum content of the M2 system (Fig. 4 c), after 7 days of hydration, clearly results in producing more ettringite ...
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