Recently, alkali-activated high calcium fly ash (FA) has been investigated for use as a repair material due to its advantage of reasonable setting time and hardening [8].It has also been shown that alkali-activated high calcium FA could be used as an alternative commercial repair material with relatively high 28-day compressive and shear bond strengths comparable …
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 fly ash is presented.
The initial setting time for low-calcium FA geopolymer paste decreased from 180 min to 120 min as the NaOH molarity increased from 10 M to 16 M. Increasing the NaOH molarity increases …
estimated at 15 % of the total cementitious binder (portland cement, fly ash, and slag) in ready-mixed concrete in the U.S., with the usage consistently trending upwards during the past ten years. With much fly ash still being diverted to landfills and existing landfills filled with fly ash
The setting time of MAPC is extended to 25 min when the spherical silica fume content is 20%. Compared with the reference, the setting time increases by 66.7%. With the increase of spherical fly ash content, the setting time of MAPC firstly increases and then decreases, reaching a maximum of 26 min at the spherical silica fume content of 15%.
A model for predicting the initial setting time of concrete with and without fly ash is presented. Based on a theoretical initial spacing between the particles of unhydrated cementitious material ...
UCS and setting time of low-calcium FA geopolymer paste for in situ applications. Keywords: geopolymer paste; compressive strength; initial setting time; final setting time; Class F fly ash; RSM 1. Introduction As of 2018, 55% of the world's population lives in urban areas. By 2050, this statis-tic is projected to reach 68% [1].
The results obtained in this study demonstrated that all sugars, including fructose, glucose, sucrose, and lactose, can prolong the initial and final setting times of high-calcium fly ash-based geopolymers. The postulated reason for increasing the setting time is the reaction between sugars and alkaline solution. •
The time of setting of fly ash paste is determined by linear interpolation of the penetration time plot [ASTM C191 (2008)]; however, its curve is largely nonlinear, thus, linear interpolation might result in interpretation errors. Most of the research work in the literature has skipped the step of determining the time of setting of fly ash and ...
Effect Of Borax On Setting Time Of Geopolymer Concrete Based On Fly Ash Type C [26] ... Geopolymer Dari Limbah B3 Fly Initial setting time 385 . Vol. 07, No. 1, February 2022: 24-28
However, when sucrose was used for high-calcium fly ash, sucrose did not prolong the initial setting time but prolonged the final setting time at 1% and 2% of sucrose incorporation [53]. In ...
Both initial setting time and final setting time of concrete increased with an increase in the replacement level of class C FA from 10 to 50 % compared to the reference concrete (Mugahed Amran et ...
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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Abstract: A survey of current literature has revealed that the testing protocol for determining the time of setting of fly ash–soil mixtures is not available. Although the current ASTM standard …
Moreover, the water-to-fly ash weight ratio of 0.35 may not be appropriate for some fly ashes because the chemical components are varied in different fly ashes. Therefore, a British fall cone was adopted to determine the time of …
The test results on the setting time of geopolymer paste show s that the fresh fly ash base d geopolymer mortar could be handled up to 120 minutes without any sign of setting for curing tem ...
This paper determines the effects of parameters such as silica to alumina (Si/Al) ratio, sodium to alumina (Na/Al) ratio, water to solid (W/S) ratio, and temperature on the setting …
AbstractIn this paper, setting time, strength and bond of high-calcium fly ash geopolymer concrete were investigated. The high-calcium fly ash was from Mae Moh power plant in northern Thailand. Both sodium silicate solution and sodium hydroxide solution ...
The results show that with smaller fly ash particles size and higher levels of fly ash replacement, the workability of the mixture was increased with longer setting time. There was an increase in mortar compressive strength with finer fly ash particle size, compared to those with unclassified ones, with the highest strength was found at those ...
Abstract: In this study, the setting time and carbonation resistance under normal laboratory conditions are evaluated for alkali-activated GGBS-fly ash blends. Three binder combinations including GGBS as sole binder, GGBS:fly ash ratio of 3:1, and GGBS:fly ash ratio of 3:1, were activated using sodium hydroxide and sodium silicates solutions with various solution alkalinities.
Studies show that the setting time (initial setting and final setting) of fly ash slag geopolymers increases with the rise of the modulus of sodium silicate solution, and the compressive strength ...
The input data required for the model are water-cementitious material ratio, fineness, specific gravity, temperature, and the blended oxide ratio: CaO/(SiO2 + Al2O3 + Fe2O3). Final setting …
In this study, the effects of the water-to-fly ash ratio (W/FA), class C fly ash (CF) content, and alkaline content on the setting times and compressive strength of geopolymer...
SEM images of the microstructure of samples with NaOH molarity of 8 M and (a) fly ash and (b) 50% fly ash/50% slag [39]. …
The setting time of class F fly ash activated by NaOH and/or Na 2 SiO 3 was tested. Results are shown in Fig. 1. It can be seen that when NaOH/Na 2 SiO 3 mixture was used as the activator and the dosage of Na 2 SiO 3 was constant, the setting time was extended with increasing the dosage of NaOH.
Fly ash prolongs the setting time either class C or class F ie high calcium or low calcium fly ash because of its low heat of hydration, which prolong the setting time and it results in low early ...
There are 4 combinations of setting time test in this research focusing on setting time of ultra fine fly ash as binder and the use of lime water as mixing water. The combinations are: a. Portland cement and tap water b. High volume raw fly ash and tap water c. High volume ultra fine fly ash and tap water d.
PDF | On Jun 15, 2024, Jabulani Matsimbe and others published Setting Time and Workability of Geopolymerized Fly Ash- Phosphogypsum Paste and Mortar | Find, read and cite all the research you need ...
The proper slag content in an alkali-activated fly ash/slag mixture was determined to be 15-20% of total binder by weight considering the setting time and compressive strength of the alkali ...
The initial and final setting time for fly-ash geopolymer paste, based on the SRPS EN 196-3 standard, has been measured upon irradiation by gamma rays in a 60Co reference field positioned with a ...
Geopolymer concrete with low calcium oxide fly ash occurs long enough hardening time. This study aims to influence the use of CaO in gypsum, lime and carbide waste in the testing of setting the time on geopolymer and conventional paste.
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.
It could be noted that porcelain-based geopolymer mix activated with alkali solution decreased the final setting time, whereas fly ash type F and ground granulated blast furnace (GGBS)-based ...
curing temperature on the setting time, on the short term engineering properties of fresh and hardened F- Type fly ash based geo-polymer mortar were studied. The Test were carried out on 70.6x70 ...
The results show that increasing the NLS dosage from 0% to 1.0% increased the initial setting time from 9.6 hrs to 15.5 hrs and the final setting time from 12.1 h to 19.7 h. However, a further increase in NLS from 1.0% to 2% had negligible influence in the initial setting time and reduced the final setting time.
Low calcium fly ash retard the setting of cement. Fly ash prolongs the setting time either class C or class F ie high calcium or low calcium fly ash because of its low heat of...