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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 14 Abstracts search results
Document:
SP96-08
Date:
January 1, 1987
Author(s):
H. A. Welton
Publication:
Symposium Papers
Volume:
96
Abstract:
A brief discussion of consolidation of concrete aimed toward the users of concrete is presented to encourage the use of vibration in improving the quality of the finished product. Significant points leading to successful consolidation of quality concrete include the interrelationship of proportioning, mixing, placement, and application of the vibrator to break down mechanical stacking, eliminate unintentional air voids, reduce residual water content, and achieve densification and enhancement of the micro-structure of the concrete.
DOI:
10.14359/3507
SP96-11
Mikael P. J. Olsen
The main purpose of concrete consolidation is to reduce the amount of entrapped air and densify the concrete. This can be accomplished by subjecting the concrete to vibration. A recently completed laboratory and field investigation to determine the movements occurring in the fresh concrete during the consolidation process is reviewed and data is presented regarding the relationship between energy level in the concrete and the degree of consolidation achieved. Accelerometers were used to measure the movement of the fresh concrete as a function of time. For the particular concrete mixes tested, a minimum energy of approximately 300 ft-lb (407 N-m) has been found to result in a degree of consolidation of 97 percent or more.
10.14359/3508
SP96-06
E. K. Schrader
Roller-compacted concrete (RCC) is rapidly becoming a popular material for dam construction, heavy-duty paving, and mass fill applications. Its economy comes primarily from being able to transport and place it in large quantities with minimal time and labor by using earthmoving or conveyor equipment. The no-slump mix is spread with bulldozers and compacted into a solid mass with large vibratory rollers. The effect of compaction methods, water content, and other variables on density, pore pressure, practical construction problems, and permeability are discussed.
10.14359/3510
SP96-04
Current consolidation practices and a recently completed laboratory investigation to determine the effects of coarse aggregate factor, maximum aggregate size, vibrator spacing, and the method of vibrator mounting on the achieved consolidation of CRCP is reviewed. The theory and principles of consolidation by internal vibration are also reviewed. Vibrator spacing, concrete mix design, and acceleration in the concrete are parameters found to be important. A vibratory spacing of 24 in. (610 mm) is required to produce adequate consolidation. The concrete mix should contain coarse aggregate with a top size of 1 « in. (40 mm) and a coarse aggregate factor determined by the Fineness Modulus Method of mix design. The superplasticizers with or without retarders have to be used with great caution due to slump loss, making it difficult to consolidate the stiff concrete mixes used in slipformed paving construction.
10.14359/1989
SP96-05
Kuo-Ting Lin, Antonio Nanni, and Wen Chang
Industrial and mining wastes, often extremely fine-grained, are being used as fillers and binders in structural concrete and consolidation by compaction, as opposed to high-frequency vibration. Impact and static compaction can be industrially used for the automatic production of such building elements as bricks and blocks, whereas roller-compacted concrete is more suitable for field applications. Compressive strength characteristics under air-dry, sealed, and soaked conditions of portland cement mixtures containing a complete range of combinations of dihydrate phosphogypsum (by-product of the phosphate fertilizer industry) and fine aggregate (crushed lime rock) are presented. Cylindrical specimens were prepared according to the Modified Proctor procedure (impact compaction). Based on these results, strength comparisons are made for selected constituent proportions in the cases of: 1) consolidation by static compaction; 2) consolidation by high-frequency vibration; 3) site consolidation by vibratory roller compactor; and 4) substitution of the dihydrate phosphogypsum with the hemihydrate form (other available by-product). It is shown that consolidation by compaction is advantageous because of the contribution of phosphogypsum to strength development. Laboratory-compacted samples of the by-product alone indicate that strengths of over 1000 psi (6.89 MPa) can be achieved. In addition, low-cement (7.5 percent) mixtures using hemihydrate gypsum waste exceed the 4000 psi (27.56 MPa) mark.
10.14359/2002
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