The workability of concrete

Murdock, L J

doi:10.1680/macr.1960.12.36.135

Cited by 28 publications

(9 citation statements)

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“…Best results could be obtained by Minimum Voids method with super plasticizer. This is also justified by lower Surface Index Factor by Murdock (1960). 5.…”

Section: Discussionmentioning

confidence: 93%

“…Addition of fly ash as replacement of sand has more pronounced lubricating effect in the concrete and hence concrete becomes more workable. This is also justified by lower Surface Index Factor by Murdock (1960). Increase in the slump was about 25% and 70% over control concrete with partial replacement of sand with fly ash and addition of super plasticizer along with partial replacement of sand with fly ash respectively.…”

Section: Workabilitymentioning

confidence: 89%

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Comparative long term study of concrete mix design procedure for fine aggregate replacement with fly ash by minimum voids method and maximum density method

Pofale

Deo

2010

KSCE J Civ Eng

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Replacement of scarcely available natural sand with fly ash has economical and environmental advantages. However due to lack of knowledge people avoid using fly ash at construction sites, which is increasing area under land bank. The paper presents the results of experimental investigation, which indicated about 20% increase in the compressive strength and about 15% increase in flexural strength of concrete by the inclusion of fly ash as a partial replacement of sand as compared to control concrete. Sand was replaced by fly ash by Maximum density method and Minimum voids method. Addition of 0.5% super plasticizer could achieve about 30% increase in the compressive strength and about 20% increase in flexural strength of concrete by the inclusion of fly ash as a partial replacement of sand as compared to control concrete. Results indicated increase in workability for all the cases over control concrete. Concrete with fly ash was also found to be about 25% economical when cost per N/mm 2 was compared. Based on experimental results correlations are developed to predict Compressive Strength, Flexural strength, cost per N/mm 2 , Slump and Dry Density for percentage sand replacement with fly ash.

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“…Best results could be obtained by Minimum Voids method with super plasticizer. This is also justified by lower Surface Index Factor by Murdock (1960). 5.…”

Section: Discussionmentioning

confidence: 93%

Section: Workabilitymentioning

confidence: 89%

Comparative long term study of concrete mix design procedure for fine aggregate replacement with fly ash by minimum voids method and maximum density method

Pofale

Deo

2010

KSCE J Civ Eng

View full text Add to dashboard Cite

show abstract

“…This concrete also has lesser voids hence more cement paste will be available for lubrication and hence concrete becomes more workable. This is also justified by the lower Surface Index Factor by Murdock [18]. Increase in the slump was about 25 mm and 65 mm over the control concrete with the partial replacement of the sand with the fly ash without and with the super plasticizer, respectively.…”

Section: Workabilitymentioning

confidence: 84%

“…5) Slump was higher without and with super plasticizer in fly ash concrete over control concrete due to lubrication, ball bearing effect and better packing due to fly ash. This is also justified by lower Surface Index Factor by Murdock [18]. The higher slump and better packing has resulted in higher ultrasonic pulse velocity.…”

Section: Discussionmentioning

confidence: 99%

Parametric Study for Replacement of Sand by Fly Ash for Better Packing and Internal Curing

Deo

Pofale²

2015

OJCE

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The use of fly ash as replacement of sand is an economical solution for making green and denser concrete. The paper presents a concrete mix design procedure for partial replacement of sand with fly ash. Present method could produce additional compressive and flexural strength for concrete with partial replacement of sand with fly ash over control concrete, with higher slump. Addition of 0.5% super plasticizer could further improve compressive and flexural strength with higher slump over control concrete. Concrete with sand replaced by fly ash was also found to be economical without and with super plasticizer, when cost per N/mm 2 was compared. The beneficial effect may be attributed to better packing, pozzolanic activity of fly ash and internal curing by fly ash as partial replacement of sand. Based on experimental results, correlations are developed to predict compressive strength, flexural strength and cost per N/mm 2 for percentage sand replacement with fly ash.

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“…The dust of fracture microfines created by the crushing of manufactured sand can be used in concrete if they are of suitable quality [6][7][8][9][10]. In fact, limestone fillers are used successfully in concrete in many parts of the world [11].…”

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confidence: 99%

Use of Chemical Admixtures to Modify the Rheological Behavior of Cementitious Systems Containing Manufactured Aggregates

Jeknavorian¹,

Koehler²

2012

JCEA

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Abstract:The use of local materials is an important part of sustainability for the concrete industry. The declining availability of aggregate resources in many areas has the potential to result in the use of alternative aggregates of lower quality, which can require higher cementitious materials contents, or the use of aggregates shipped from greater distance. In some markets, manufactured sands are replacing natural sands, which can adversely impact the rheology of cementitious mixtures. The use of certain chemical admixtures has been found to often minimize the need to increase cement and water contents in order to overcome the loss of workability that can accompany aggregate sources which feature flat, elongated, angular, and rough particles. In this study, a wide range of natural and manufactured sands were characterized for gradation, mineralogy, shape, texture, and cleanliness, and also evaluated for their effect on mortar rheology with and without a VMA (viscosity modifying agent) type chemical admixture. Use of the VMA is shown to mitigate the rheological effect of certain sands, and in some cases can allow for optimizing the mixture to lower paste contents. In the case of PCP (polycarboxylate)-based superplasticizers, attention is drawn to the increased dose required to achieve target workability versus superplasticizers based on NSFC (naphthalene sulfonate condensate) when swellable clays are present in the very fine fraction of certain aggregate sources. The use of sands with higher fines contents are also shown to increase the workability provided the fines are of appropriate quality.

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The workability of concrete

Cited by 28 publications

References 0 publications

Comparative long term study of concrete mix design procedure for fine aggregate replacement with fly ash by minimum voids method and maximum density method

Comparative long term study of concrete mix design procedure for fine aggregate replacement with fly ash by minimum voids method and maximum density method

Parametric Study for Replacement of Sand by Fly Ash for Better Packing and Internal Curing

Use of Chemical Admixtures to Modify the Rheological Behavior of Cementitious Systems Containing Manufactured Aggregates

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