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In this video I Dr Anjali Ssaxena have explained the Setting and Hardening of Portland cement with its chemical reactions I have also explained the
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The initial and final setting times increased exponentially with the concentration of saccharide although the hydration of OPC was less inhibited than that of C3S Saccharides function as delayed accelerators that is cement hydration is first inhibited and then proceeds faster than in saccharide free cement
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Effect on setting times of Cement The initial and final setting times of cement for different KCL concentrations are compared with control samples If the difference is less than 30 minutes the change is considered to be negligible and if the difference is more than 30 minutes the change is considered to be significant The effect of KCl on
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Appreciable amounts >1% in cement make set control difficult and the cement becomes excessively hygroscopic The cement powder flowability is reduced and air set lumps tend to form They withdraw water from gypsum on storage of the cement leading to false set For this reason their formation is avoided wherever possible
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Jul 19 2022It is found that additional of calcium stearate in cement reduces initial setting time of cement The higher content of calcium stearate the lower of initial setting time Additional of calcium stearate 3% by weight of cement reduce the initial setting time from 129 to 111 min
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Conclusions Addition of 15% glycerin to Portland cement has improved the setting time the cohesiveness and the anti washout ability of the cement with subsequent improvement in the handling properties as well as increasing its compressive strength This trial is considered to be a successful
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Jun 9 2021The cement setting time tests are relevant for cement manufacturers but are hard to use in construction projects This is because for the tests for the cement setting times only pure cement and water are used neglecting the effect of aggregates and admixtures Therefore the most relevant test to do is the concrete setting time The standard
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Carbonates and bicarbonates are two groups of accelerators which can be used in sprayed concrete In this study the effects of the two accelerators sodium carbonate
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The effects of ethylene glycol on the setting reactions of hydrating Portland cement and on the eventual structure of the hydrated cement paste have been studied by a combination of techniques including solvent extractions with solvents of varying polarities scanning electron microscopy and X ray powder diffraction
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This paper investigated the effect of organic compounds with ester groups on the hydration and hardening of cement The effects of five kinds of organic compounds with ester groups ethyl acetate dimethyl oxalate glyceryl triacetate trimethyl phosphate and triethanolamine borate on hydration heat hydration degree setting time mechanical properties microstructure and pore structure of
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In brief Portland cement is produced by crushing and grinding calcareous materials limestone chalk and argillaceous materials clay shale as a wet slurry or in a dry state The mixture is Information on the adverse health effects of cement dust comes from observations of its effects in humans As noted in the earlier HSE 1994
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Except for the control mixture boric acid BA was used at the ratios of % of weight of cement in mortar mixtures with Portland cement Setting times dependent on pH EC and T changes of
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The ratio of cement mortar must be 1 3 standard cement and sand The initial setting time of this cement is not less than 30 minutes and final setting time should not exceed 10 hours Also read Complete Guide on Grades of Concrete Properties and Uses of Ordinary Portland Cement It is commonly used for works for various engineering
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The comparison of effects of each boron containing compound is based on its concentration and on its kind Access through your institution Add to Cart Utilization of borogypsum as set retarder in Portland cement production Cement and Concrete Research 2024 vol 32 issue 3 s 471 475 DOI /s0008 8846 01 00711 6 Cited by
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Apr 22 2021This article presents a study of the effect of water glass and its introduction on the hydration of Portland cement and its properties in plastic and solid states The introduction of sodium water glass into the mixing water extends the setting time of Portland cement by 35% while introduction into the cement paste reduces it by % for potassium water glass the respective values are
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Make sure you choose a setting type joint compound which is easy to a water based colloid used as an elastic impression material Reversible Hydrocolloid an agar impression material that can be heated to change a gel into a fluid sol state that can flow around the teeth then cooled to gel again to make an impression of the shapes of the oral structures
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Cold Weather Concreting Portland Cement Association Effects on Setting and Linear Changes of Sorel s Cement 415 Table 3 Effect of Portland cement on moisturizing ingress characteristics of oxysulphate cement Conc of g s 25 O Be Dry mix composition 1 2 Volume of g s 70 mL One part by weight of magnesia Temperature 30 ± 2 OC Two parts by weight
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Water H 2 O is a polar inorganic room temperature it is a tasteless and odorless liquid nearly colorless with a hint of simplest hydrogen chalcogenide is by far the most studied chemical compound and is described as the universal solvent for its ability to dissolve many substances This allows it to be the solvent of life indeed water as found in nature almost
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Jan 21 2021Lei [ 16] et al explored the effect of maltodextrin on Portland cement mortar and considered that the retarding mechanism of maltodextrin stems from the surface adsorption of cement particles which leads to the reduction of ettringite and other products thus prolonging the hydration reaction
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Presence of PG improves the grindability index reduce the water demand and the initial and final setting times of both OPC and PLC mortar specimens Beside it enhances the mechanical properties especially in the early stages of hydration Keywords limestone propylene glycol grindability index setting hardening Introduction
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Apr 12 2021In this paper the effect of calcium sulfate on C 3 A C 3 S and Portland clinker hydration are reviewed as well as the influence of the amount of sulfate on cement properties Presented within are the main factors that may influence the optimum sulfate content and the methods that can be used to determine the sulfate demand
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At the time of the final cement setting there is a sharp drop in the electrical conductivity of the cement paste and attempts have been made to measure setting by electrical means The setting time of cement decreases with a rise in temperature but above about 30 °C a reverse effect may be observed At low temperatures setting is retarded
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Factors affecting the setting time of cement are discussed below in detail 1 Retarders Adding retarders like gypsum decreases the setting of cement and the setting time is increased Retarders are mixed with clinkers before final grinding or just after preliminary grinding of clinker 2
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A novel double sulfate composite early strength agent DSA incorporating aluminum sulfate and sodium sulfate was developed to improve the early strength of Portland cement paste The effect of the DSA dosage on the setting and hardening properties hydration process hydration product composition microstructure and pore structure of the Portland cement paste was investigated to reveal its
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Since the antimicrobial ingredients in the root canal sealers do not have selective toxicity against microorganisms they may also show toxic effects on host cells According to the current study AH 26 sealer with the mean growth of mm and MTA sealer with mean growth of mm had the highest antimicrobial effects
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The data shown in Table 1 indicate that the limestone content of cement can be increased from the level typically used in conventional portland cement about % to 15% while maintaining equivalent performance This can result in reduced environmental impact and in some cases reduced cost
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The use of ecological materials for building and industrial applications contributes to minimizing the environmental impact of new technologies In this context the cement and geopolymer sectors are considering natural fibers as sustainable reinforcement for developing composites Natural fibers are renewable biodegradable and non toxic and they exhibit attractive mechanical properties in
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Aug 31 2021Gypsum is mostly used for regulating the setting time of cement and it is a very vital component Overmuch gypsum will speed up the setting of cement and this will lower the strength of the cement Therefore the quantity of gypsum should fall around 3% 5% of the cement s mass Quantity Of Mixing Water Content
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Grinding in generally are classified according to their structures into glycols alkanol amines and phenol type compounds 3 4 In addition to increase the efficiency of cement mill grinding aids could effects on the fresh cement paste properties and so they could improve the strength development of the setting concrete
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