Evaluation of Admixtures for Use in Concrete to be Placed Underwater
Evaluation of Admixtures for Use in Concrete to be Placed Underwater

Author: William O. Tynes

Publisher:

Published: 1976

Total Pages: 23

ISBN-13:

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Concrete without admixture and concrete containing either a plasticizer ('fluidifier') or a retarder were mixed and deposited underwater using the tremie method. The tremie used consisted of a pipe topped with a receiving funnel and plugged at the discharge end to keep the pipe sealed until filled with concrete. Tests were conducted with a number of batches of concrete to determine the slope and distance the concrete flowed. The tests were made to determine if these commercially available admixtures when used in concrete to be placed underwater increase the flowability of the concrete. Test results indicated that the use of either a retarding admixture or a plasticizer did not increase the flowability of equal-slump concrete, regardless of point of tremie discharge. The slope was not significantly affected by either a retarding admixture or a plasticizer. The concrete containing either a retarder or plasticizer appeared to be more cohesive and developed less laitance than equal-slump concrete without these admixtures. (Author).

Evaluating Air-entraining Admixtures for Highway Concrete
Evaluating Air-entraining Admixtures for Highway Concrete

Author: Mohamad Nagi

Publisher: Transportation Research Board

Published: 2007

Total Pages: 60

ISBN-13: 0309098890

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"This report presents a recommended procedure for evaluating air-entraining admixtures used in highway concrete. The procedure involves the testing of non-air-entrained concrete and concrete containing the air-entraining admixture under simulated field conditions. Criteria are proposed for acceptance of admixtures for use in either highway pavements or structures. The recommended procedure and acceptance criteria will guide materials engineers in evaluating and selecting air-entraining admixtures that should contribute to appropriate freeze-thaw durability and thus to good performance and long service life. The content of the report will be of immediate interest to materials engineers, researchers, and others concerned with the design of concrete mixtures for use in highway pavements and structures."--taken from Foreword, page [v].

Application of Admixtures in Concrete
Application of Admixtures in Concrete

Author: A.M. Paillere

Publisher: CRC Press

Published: 2004-03-01

Total Pages: 140

ISBN-13: 0203626397

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This book provides a thorough review of the properties and use of the principal chemical admixtures for use in concrete. Concise and clearly presented, the book includes extensive references to key sources of information. The presentation of each admixture is in a standard format, which helps the reader to find relevant information easily.

Concrete Admixtures Handbook, 2nd Ed.
Concrete Admixtures Handbook, 2nd Ed.

Author: V.S. Ramachandran

Publisher: William Andrew

Published: 1996-12-31

Total Pages: 1183

ISBN-13: 0815516541

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Since the publication of the first edition ten years ago, significant developments have occurred in the use of admixtures in concrete. Eight new chapters and a full update of the preceding ten chapters bring this book up to date; reflecting the relative advances made in the science and technology of different groups of admixtures. The increased role and development of admixtures in concrete technology is evidenced by a number of conferences, publications, and novel admixtures available in the market place. These developments in the field caused the modification of many chapters in the first edition in order to reflect the advances. Although individual chapters refer to standards and specifications of admixtures, those only interested in the standards or techniques used in investigating admixtures will find the second chapter (Research Technologies, Standards, and Specifications) useful. Admixtures are not as inert as may be presumed. They may chemically interact with the constituents of concrete and affect the properties of the fresh and hardened concrete and its durability. The third chapter deals with these aspects. It was important to devote a chapter to recent attempts in developing new admixtures.

Repair, Evaluation, Maintenance, and Rehabilitation Research Program: Evaluation of Concrete Mixtures for Use in Underwater Repairs
Repair, Evaluation, Maintenance, and Rehabilitation Research Program: Evaluation of Concrete Mixtures for Use in Underwater Repairs

Author: Billy D. Neeley

Publisher:

Published: 1988

Total Pages: 134

ISBN-13:

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Concrete mixtures were evaluated to determine which were most suited for placement underwater in thin lifts. The concretes were proportioned to have good workability, good abrasion erosion resistance, and good resistance to washing out of the cement paste. High-range water reducers (HRWR) were used to increase the workability and permit the use of low water cement ratios (W/C) to increase the resistance to abrasion erosion. Low W/C, silica fume, and antiwashout admixtures (AWA) were used to increase the resistance to washout. A washout test was used to determine the relative amount of cement paste lost when the concrete is exposed to a large volume of water. The two-point workability test was used to evaluate the relative workability properties of each mixture. The slump and air content were also measured for most of the mixtures. The test method for abrasion erosion resistance of concrete (underwater method) was used to determine the abrasion erosion resistance of each mixture. The results of these tests were used to determine the combination of materials necessary to produce concrete with the desired properties. Significant correlations that exist between the two-point measurements and washout measurements were examined. The effects that W/C, HRWR's, AWA's, fly ash, and silica fume have upon washout resistance and abrasion-erosion resistance were examined.