Study on Improvement of Vibration Compaction Performance of Fresh Mortar

Takehisa, Daiki; Ide, Ichio; Hashimoto, Shinichiro; Date, Shigeyuki

doi:10.18178/ijscer.7.1.40-45

Cited by 4 publications

(8 citation statements)

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“…8 show the relationship between the vibration plasticity viscosity and the 150mm filling time and the relationship of V-pass when the mixing ratio of fine aggregate is changed. In previous research using natural sand, it is reported that as the plastic viscosity under vibration is smaller, the 150mm filling time becomes shorter and the V-pass becomes faster [11][12]. From Fig.…”

Section: ) Bfs Ratio Vs Plastic Viscositymentioning

confidence: 71%

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Influence of Replacement Rate of Fine Aggregate by Blast Furnace Slag Sand on Fresh Properties of Mortar

Takehisa

Takahashi²,

Hashimoto

et al. 2018

KEM

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For enlarging and promoting usage of blast furnace slag sand and improving construction performance of concrete with it, the behavior of the mortar under both static and dynamic, using vibrator, conditions were confirmed from the viewpoint of plastic viscosity, filling property and bleeding rate. As the results, within the scope of this experiment, by investigating the mixing ratio at which the plastic viscosity changes from the vibration plasticity viscosity obtained by the feather penetration type viscosity measurement test, it was considered that the appropriate fine aggregate mixing ratio can be estimated. Furthermore, the pore water pressure was measured for a sample in which the mixing ratio of the fine aggregate was changed, and the possibility of evaluating the fresh properties from the tendency of disappearance of pore water pressure after stopping the vibration was indicated.

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Section: ) Bfs Ratio Vs Plastic Viscositymentioning

confidence: 71%

“…From the results, in order to determine the proper mixing ratio when using BFS and natural sand, applicability of the feather penetration type viscosity measurement test was examined. Furthermore, the relation between bleeding and pore water pressure reported in the past study was examined from different perspectives [11][12].…”

Section: Introductionmentioning

confidence: 99%

Influence of Replacement Rate of Fine Aggregate by Blast Furnace Slag Sand on Fresh Properties of Mortar

Takehisa

Takahashi²,

Hashimoto

et al. 2018

KEM

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“…A schematic of the viscometer used to quantify the plastic viscosity of the mortar [14,15] is shown in Fig. 2.…”

Section: Experimental Methods 1 Plastic Viscositymentioning

confidence: 99%

Effects of Silica Fume Addition on Properties of Fresh Mortar

Takigawa

Koyama

Uno

et al. 2021

MSF

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In recent years, concrete structures have tended to be taller and larger than before. With that trend, concrete as a material has diversified, and various kinds have been developed to meet differing quality requirements. In particular, the need for high-strength concrete is increasing. In general, high-strength concrete has a low water-binder ratio, so its workability is inferior to general concrete. Including admixtures such as silica fume is one way to remedy this problem. Previous studies have discussed the quality and hardening characteristics achievable using silica fume. Nevertheless, expected increasing demand for high-strength concrete dictates the need to understand not only its properties when fresh, but also to have an accurate picture of its vibration compaction properties on construction sites. In this study, the effect of adding silica fume on the workability of mortar was investigated by evaluating its fresh properties, plastic viscosity, and vibration propagation characteristics. Changes to mortar’s fresh properties due to pressure were also investigated to clarify its behavior in pumping environments. The study confirmed that the addition of silica fume decreases plastic viscosity and increases vibration propagation characteristics, and that increased plastic viscosity due to pressurization can be reduced.

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“…To measure the effect of thermal stimulation on the rheological properties of mortar, a blade viscometer was used to assess plastic viscosity (Takehisa et al 2018;Muroga et al 2000). A schematic of the blade viscometer is shown in Fig.…”

Section: Plastic Viscosity Of Mortarmentioning

confidence: 99%

“…In this study, the acting buoyant force while the blades dropped into the fresh mortar and the shear area were assumed to be constant, as the blades were completely submerged in the fresh mortar when the measurement started. A table vibrator with a frequency of 40 Hz (amplitude: 1 mm) was used for measurements under vibration, similar to the procedure in a previous study (Takehisa et al 2018).…”

Section: Plastic Viscosity Of Mortarmentioning

confidence: 99%

Effectiveness of Thermal Stimulation of Superplasticizers on Fresh Properties of Cement Mortar

Takigawa

Nemoto

Hashimoto

et al. 2021

Iran J Sci Technol Trans Civ Eng

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Polycarboxylic acid-based superplasticizers are used in various types of concrete work. Wide variations in environmental temperatures are known to affect how well chemical admixtures perform as superplasticizers, influencing the properties of the concrete. However, little has been reported on changes in performance caused by thermal variations. Previous studies have reported that heating superplasticizers change the polymer structure, improving and sustaining cement particles' dispersibility. Moreover, the improved fluidity from thermal stimulation is not temporary. The effect has been observed to remain for about seven days, with the residual characteristics differing depending on the superplasticizers used. Therefore this study evaluates mortar stiffness when using thermally stimulated superplasticizers and evaluates how the stimulation affects construction performance using measures such as the flow and rheological properties (plastic viscosity) of fresh mortar, vane shear tests, blade viscometer tests, and mortar vibration box tests. Mortar's fluidity was found to improve by about 25% when using thermally stimulated additives, with plastic viscosity dropping by up to 45% and the stress likely to be needed for pumping also being reduced by about 16%. Filling speed was also found to increase by about 26%. Thus, thermal stimulation improves mortar and concrete construction performance, and it may be possible in the future to carry out the construction with fewer workers utilizing this technology’s benefits. The study indicates a need for further investigation of how thermal stimulation affects polymer molecules’ adsorption efficiency with cement to elucidate the mechanism at full scale and propose ways to adopt thermal stimulation at actual construction sites.

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Study on Improvement of Vibration Compaction Performance of Fresh Mortar

Cited by 4 publications

References 0 publications

Influence of Replacement Rate of Fine Aggregate by Blast Furnace Slag Sand on Fresh Properties of Mortar

Influence of Replacement Rate of Fine Aggregate by Blast Furnace Slag Sand on Fresh Properties of Mortar

Effects of Silica Fume Addition on Properties of Fresh Mortar

Effectiveness of Thermal Stimulation of Superplasticizers on Fresh Properties of Cement Mortar

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