This study evaluated the effect of initial molar ratios SiO 2 /Al 2 O 3 and (CaO + SiO 2)/Al 2 O 3, on the setting time of mortar with alkali-activated Ground Granulated Blast Furnace Slag (GBS) and fly ash (FA) binders.The study also evaluated the chemical resistance of alkali-activated mortar and the effect of NaOH alkaline activator on resistance to sulfuric acid in …
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Anti-crack performance of concrete with phosphorus slag and fly ash singly and compositely added is investigated in terms of physical performance, hydration heat, dry shrinkage and creep, and ...
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The early strength of the geopolymer formed by the incorporation of GGBS in fly ash was improved and the setting time was ... the overall initial and final coagulation times were relatively long in Group A and shorter in Group C. ... all COSGM samples in Table 4 meet the requirements of fluidity and setting time of cement (GB175–2023), and ...
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Accelerators are used in cementitious materials for augmenting the rate of early age strength and/or abbreviating the time of setting for the fill to pass from plastic to solid state [55, 56].They are widely used to obtain high early strengths in sprayed concrete applications, providing setting start in a short time and eliminating rebound problem [[57], [58], [59]].
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The first experiment tests the strength of cement mixtures with different ratios of cement, sand, lime, fly ash and rice husk after 3 days. The second experiment tests the strength of three cement mixtures over time at 3, 10, and 20 days. ... Effect of time on setting of cement mortar. Time has an important role on the strength developed by ...
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The coagulation structure Si–OH and Al–OH was formed due to the reaction of Ca(OH) 2 with Si + and Al + in CFBC fly ash. The main hydration products of the CFBC fly ash and coal-fired fly ash are C–S–H and C–A–H gels. ... Effect of fineness and content of fly ash on setting time of Portland cement. Cement, 12 (2003), pp. 4-6. Google ...
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The results illustrate that with 25% replacement (wt%) of cement by fly ash, the compressive strength (one day to one year) and the flexure strength (at 56th day curing) of cofired and blended ...
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identified the two primary causes preventing increased use of fly ash in ready-mixed concrete: 1) performance issues including setting time and strength gain, and 2) specifications that restrict usage.
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The findings demonstrated that the CaO level in the fly ash impacted the setting time, with those with a CaO content of less than 10% taking a longer time to set, while those with more than 10%...
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setting time and workability. It was found that an increase in the PG wt% led to a decrease and/or acceleration in the initial setting time (INSET) and final setting time (FINSET) attributed to the rapid dissolution of Ca. 2+ in low alkaline concentrations outnumbering that of Al. 3+ and Si. 4+
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56 days to identify the strength development of each sample. The result revealed that the content of CaO in fly ash affected the setting time and early strength development. In three days paste …
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Portland cement addition, fly ash content and solution resting time were studied.. The study focused on curing temperature and curing period. • Performance and mechanical properties of GPC were evaluated for all factors.. Portland cement addition up to 15% improves GPC properties except workability.. Solution resting time for 30 min yields higher performance.
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Keyw ords: high -calcium fly ash, geopolymer paste, setting time, compressive strength. Abstract . Fly ash based geopolymer normally gets the optimum strength by heat curing.
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There are many factors affecting the characteristics of cement-fly ash slurry in practical engineering. Thus, this paper studies the influence of multifactors on the fluid properties of cement-fly ...
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The setting time of MKPC was determined using a Vickers meter, and the initial setting time was taken as the final setting time. The Chinese standards GB/T 1346, "Test Methods for Water Consumption, Setting Time, and Stability of Standard Consistency of Cement," and JC/T 2537–2019, "Magnesium Phosphate Repair Mortar," were consulted for ...
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The results show that as the temperature increases, the initial and final setting times decrease for all types of concrete, with fly-ash concrete having the longest setting …
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Electrical resistance (or heat flow) measurements can be used to adequately predict a mixture's initial setting time for a wide variety of binary and ternary powder blends, …
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This research investigates the setting time and workability of geopolymerized fly ash-phosphogypsum paste (GPP) and mortar (GPM) using a Vicat needle procedure per ASTM …
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12 CEMENT, CONCRETE, AND AGGREGATES TABLE 1--Chemical composition and physical properties of cementitious materials. Cementitious Material, % Item Type I Cement Fly Ash Slag SiO2 20.96 50.90 35.32
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penetrometer to test the strength gain versus the time of setting. Additionally, the fly ash–soil mixture has a time of setting that is slightly different from that of fly ash itself. The time of setting of fly ash–soil mixtures directly relates to the compaction delay (Misra 1998; Mackiewicz and Ferguson 2005; Senol et al. 2006).
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Zheng et al. investigated the rheological properties of Portland-fly ash cement paste containing a high volume of FBC fly ash and found that when the FBC fly ash content exceeded 50% by …
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Title: Prediction of Setting Time of Fly Ash Concrete Author(s): J. J. Brooks Publication: Materials Journal Volume: 99 Issue: 6 Appears on pages(s): 591-597 Keywords: concrete; factors; fly ash; penetration; prediction; setting time DOI: 10.14359/12369 Date: 11/1/2002 Abstract: A model for predicting the initial setting time of concrete with and without …
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Initial setting time (161–207 min) and final setting time (215–310 min) results are within limits stipulated in ASTM C150 for Type I Portland cement (≥45 and ≤ 375 for IST) [53]. Although normal consistency implies that the right amount of water is added for reaction and lubrication, the setting time is still influenced by the actual ...
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Using Test Method for Time of Setting of Concrete Mixtures Paste by Penetration Resistance (ASTM C 403), Proctor penetration resistance was determined under isothermal curing temperatures ranging from 6 to 80°C for concretes containing up to 50% of fly ash or ground-granulated blast-furnace slag.
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According to the results, they introduced fuzzy logic approaches that establish correlation among cement's setting time, the silica fume and fly ash [30]. Tanyildizi investigated a fuzzy logic ...
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fly ash slightly retards the setting time of concrete. It was also found that the rate of strength development at various ages is related to the w/c ratio and percentages of fly ash in the concrete mix. Moreover, the modulus of elasticity of fly ash concrete also reduced with the increase in fly ash percentage for a given w/c ratio. 2.
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However, I've heard that fly ash retards setting, which would be undesirable when using the mix in cool weather. Is it possible to add fly ash without affecting the concrete setting time? Fly ash doesn't chemically retard setting. But many times fly ash is used in concrete as a cement replacement in combination with a water reducer.
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The setting time results indicate that when the cement composition consists of only 30 % G oil well cement and a large proportion of fly ash(65 %∼70 %), the setting time is prolonged, especially at low curing temperature (3°C,10°C). On the other hand, with a high proportion of fly ash, the early compressive strength is quite low.
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Therefore, the hydration rate of cement is decreased with the increasing dosages of fly ash, leading eventually to increasing the setting time, as observed in Figure 4, and relationships between ...
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As was known, the cement paste exhibited in a thixotropic manner upon cyclic application and removal of shear rate or stress (Chen et al., 2012; Quanji et al., 2014;Roussel, 2005), expressed ...
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