Retempering of plain and super plasticised concretes

Ravindrarajah, R. Sri; Tam, C. T.

doi:10.1016/0262-5075(85)90005-3

Cited by 2 publications

(5 citation statements)

References 3 publications

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“…More recently, others have reported similar results indicating that the final water·cement ratio is the governing factor controlling the strength of retempered concrete. [9,13,30] Hawkins found that retempering reduced the compressive strength, but not as much as would be predicted by the final water·cement ratio.…”

Section: Effect Of Hot Yeathermentioning

confidence: 96%

“…This extension of mixing time provided up to a 25 percent increase in strength for mixes in a study done by Ravindrarajah and Tam in which non-air-entrained concrete was used. [30] An increase due to prolonged mixing after retempering shows the same characteristics of gain in strength as concrete which has not been retempered.…”

Section: Effect Of Mixing Timementioning

confidence: 96%

“…[28] Ravindrarajah and Tam supported this conclusion and found additionally that the rate of slump loss increases as the number of retemperings increases. [30] Conventional water-reducing, set-retarding admixtures did not have a significant effect in reducing slump loss in the study done by Previte. [27] This is because these admixtures affect the concrete by extending the dormant period.…”

Section: Slump Loss Andmentioning

confidence: 98%

“…Extending the mixing time of concrete tends to increase the concrete strength. [9,11,12,18,28,30] This mainly occurs due to the loss of water through evaporation and absorption by the aggregates, reducing the effective water-cement ratio. Additionally, loss of air is encountered in air-entrained concretes.…”

Section: Effect Of Mixing Timementioning

confidence: 99%

“…In ~rder to evaluate the effects of withholding time, amount of water withheld, and cement content upon the physical properties of 29 30 concrete, a testing program was devised which would incorporate all variables in a total of twelve ready-mixed truckloads.…”

Section: Testing Seriesmentioning

confidence: 99%

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Effects of Withholding Mixing Water and Retempering on Properties of Concrete

Anderson¹,

Carrasquillo²

1993

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I Durability of Cotlcrete"The effects of withholding mixing water at initial hatching followed by retempering of the mix at the jobsite on the properties of the concrete produced for highway applications was examined in an experimental program. Additionally, the effects of redosage with water above and beyond that called for in the specified mix design was examined. Tests were performed to determine the effects on slump, air content, unit weight, compressive strength, flexural strength, abrasion resistance, and freeze-thaw resistance.The effects of varying the withholding amount, withholding time, and cement content on the fresh and hardened concrete properties mentioned above were examined. The concrete examined was produced at a ready-mixed concrete facility in order to duplicate as closely as possible job-site conditions arising in typical concrete construction.The results of the study show that significant detrimental effects occur when mixing water is withheld and concrete is retempered at a later time. Slump, air content, abrasion resistance, and freeze-thaw resistance are all adversely affected. The effects were found to vary with variations in both withholding time and cement content. The strength was not affected when water was withheld and concrete was retempered, but a reduction in strength accompanied an increase in water-cement ratio above design values at redosage. The properties changed lead to concrete of reduced quality and questionable performance. 17.

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Section: Effect Of Hot Yeathermentioning

confidence: 96%

Section: Effect Of Mixing Timementioning

confidence: 96%

Section: Slump Loss Andmentioning

confidence: 98%

Section: Effect Of Mixing Timementioning

confidence: 99%

Section: Testing Seriesmentioning

confidence: 99%

See 3 more Smart Citations