Analysis of mechanism on water-reducing effect of fine ground slag, high-calcium fly ash, and low-calcium fly ash

Effect of Calcareous Fly-ash Processing Methods on Rheological Properties of Mortars

“…It should be noted that CFA containing more fine fraction has a smaller negative influence on the workability. Generally, the obtained results remain in good correlation with relevant data from the literature [2][3][4][5][6][7][8][9][10]. The addition of ground CFA causes the yield value g and plastic viscosity h of mortars to increase directly in proportion to the amount added (Figs.…”

“…However, extensive use of CFA encounters important limitations. These include: (1) the characteristics of the CFA's chemical composition, especially the high content of free lime as well as sulfate, which lead to a risk of a potential negative influence on the properties of concrete, (2) the variability of the physicochemical properties of CFA, which makes it difficult to control the properties of concrete, and (3) the high water demand of CFA, which has a negative impact on the workability of fresh concrete, especially with regard to the aspect of loss of workability over time [2,4,[7][8][9][10][11]. Moreover, so far, only a small number of systematic researches on the influence of CFA on concrete properties are available [1][2][3][4][5].…”

Comparative study on flexural properties of ultra-high performance concrete with supplementary cementitious materials under different curing regimes

“…The flowability of UHPC mixture with the same fly ash content was slightly higher than that with GGBS, which increased by 5, 13, and 23 mm, respectively. The improvement in flowability associated with fly ash was due to the following aspects[20]: (1) spherical shape and glassy surface -providing lubricating effect to reduce the degree of water absorption and internal friction force among the angular particles; (2) high superplasticizer absorption -increasing electrostatic repulsion and steric hindrances[21]. However, the lower flowability associated with GGBS at the same dosage might be attributed to: (1) lower SP absorption when compared to fly ash[21]; (2) more irregular and larger particles with less smoothed surface, which increases the internal friction among particles.…”

Effect of sand, fly ash, and coarse aggregate gradation on preplaced aggregate concrete studied through factorial design

“…When enough fly ash is replaced in the mixture, paste volume increases due to the lower density of fly ash compared to cement, which can form a lubricating layer between sand particles to reduce friction and increase flowability of mixtures [23]. Another reason is due to the spherical shape of fly ash particles which act as ''rollers'' between particles and improve flow, this has also been described by several researchers [24,25]. Previous researchers [26] also observed the decrease in flow time from the use of class-F fly ash in higher W/B (0.45) grouts used for PAC.…”