Effects of revibration on early age retarded concrete

Kassim, M. M.

doi:10.2495/hpsm120081

Cited by 3 publications

(6 citation statements)

References 2 publications

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“…In general, re-vibration is found to dramatically reduce the strength of the control mix MC by 24% when the re-vibrating process is produced after the final set of cement. This finding on LWC is well agreed with the results of normal weight concrete (NWC) reported by other researchers [16,18,27]. The hydration heat that is generated from the cement when contacts with moisture usually slow by adding the retarder plasticizer to the mix.…”

Section: Strength Propertiessupporting

confidence: 91%

“…This action produces a more stable and uniform compacted mixture that is less affected in revibration action at a later time. These results, which were obtained from LWC upon using a retarder agent and SF are similarly observed in other works of NWC [6,12,16,28,29].…”

Section: Water Absorption After Immersionsupporting

confidence: 87%

“…Both coarse and fine aggregates were conforming to the Standards ASTM C 330-04 and BS 882:1992 zone II [19,20]. To minimize the negative effects of re-vibration after the initial set of the cement, a retarder plasticizer was added to the mixes MR and MRS [6,16].…”

Section: Methodsmentioning

confidence: 99%

“…On the other hand, few studies were found about the re-vibration of normal weight concrete (NWC) and the evaluation of its strength properties [14,15]. Kassim [16] found that re-vibration of concrete at a later time before the final set of cement has benefited from liquefying the concrete again, which temporarily breaks down the weaker calcium hydroxide that already formed. This action enhances the compaction of the fresh concrete and produces monolithic concrete.…”

Section: Introductionmentioning

confidence: 99%

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The water permeability properties of re-vibrated lightweight concrete

Kassim

2020

J Met Mater Miner

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Re-vibration of sequential layers of relatively deep structural members after a particular time harms the strength and water permeability properties of the concrete. The harmful effects can be observed in lightweight concrete due to the floating tendency of lightweight aggregate. In this experimental study, the influence of adding retarder plasticizer and silica fume on water permeability properties of re-vibrated lightweight concrete was investigated. The effects of re-vibration at different time lags on compressive strength and permeable voids ratio were studied. Absorption, sorptivity, and water penetration depth under pressure were also studied. Results show that the addition of a retarder increased the compressive strength and reduced the permeability for all mixes, even though the mixes were re-vibrated before the final set of the cement. Similar effects were found in mixes that contained silica fume as partial replacement of cement, except the sorptivity properties of concrete when compared with the control mixture. A linear relationship between permeable voids and water absorption was set.

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Section: Strength Propertiessupporting

confidence: 91%

Section: Water Absorption After Immersionsupporting

confidence: 87%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The water permeability properties of re-vibrated lightweight concrete

Kassim

2020

J Met Mater Miner

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“…Kassim examined the effects of revibration on retarded concrete compressive strength at late lag intervals based on initial and final setting times. Various time lag intervals and cement retardant dosages are also considered [14]. The multi-vibration concept is adopted to identify the relationship between vibration duration, vibration phase, and compressive strength upgrading of single vibrated, revibrated, and multi-vibrated specimens.…”

Section: Introductionmentioning

confidence: 99%

Developing Sustainable Concrete Compaction using a Proposed Multi-vibration Technique

Zemam

2020

QJES

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This study seeks to develop a sustainable construction technique based on the introduction of a specific method for improving concrete compressive strength through a proposed multi-vibration compaction method. An experimental program is performed to evaluate the effect of the proposed compaction technique on fresh silica fume concrete undergoing the initial setting. Multi-vibration intends to minimize concrete production cost because it upgrades the compressive strength of the same materials with better utilization of the vibration energy required for compaction. The collected experimental data presented assign relationships among vibration duration, vibration cycles or phases, and compressive strength upgrading of single vibrated, revibrated, and multi-vibrated specimens for analysis and discussion. This study shows that multi-vibration phases, rather than single vibration or revibration techniques, are powerful techniques for improving concrete compressive strength. The results indicated that the existence of an optimum multi-vibration mode was dominated by phase number and vibration duration and confirm the reliability vibration overall time duration recommended by ACI 309 which relates to a single vibration time limit to be considered in the case of multi vibration technique. Multi-vibration Mode 8 (subjected to three vibration phases 10, 20, and 30 sec ) has the best effect for the considered mixtures among the specific vibration modes. The maximum improvement ratio is 1.25, which is associated with the plastic mixture.

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Effect of Re-vibration on Strength Properties of Lightweight Concrete

Kassim

2020

Advances in Civil Engineering Materials

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In relatively deep structural members, re-vibration is applied to sequential layers after they are initially hardened. This may cause harmful effects on strength properties, especially on lightweight concrete (LWC). In this experimental study, the effects of re-vibration on LWC properties were thoroughly investigated. Local lightweight crushed pumice rock named “Bonza,” as well as set retarding admixture and silica fume (SF) were used to produce four different mixes of LWC. These mixes were re-vibrated at different time lags (0:00, 2:50, 4:30, and 5:30 [h:min]). After the re-vibration process, compressive and tensile strength properties, as well as pulse velocity, density, and permeable voids volume of hardened concrete mixes, were investigated. Results showed that using the setting retarder and partial SF replacement of Portland cement, the density, compressive, and tensile strength properties were increased in all re-vibrated mixes when the re-vibration was accomplished before the final set time of the cement. A lack of correlation between ultrasonic pulse velocity, density, and compressive strength was also detected. Furthermore, a linear relationship was found between permeable voids volume and compressive strength of all mixtures.

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Effects of revibration on early age retarded concrete

Cited by 3 publications

References 2 publications

The water permeability properties of re-vibrated lightweight concrete

The water permeability properties of re-vibrated lightweight concrete

Developing Sustainable Concrete Compaction using a Proposed Multi-vibration Technique

Effect of Re-vibration on Strength Properties of Lightweight Concrete

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