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International Concrete Abstracts Portal

Showing 1-5 of 14 Abstracts search results

Document: 

SP96-05

Date: 

January 1, 1987

Author(s):

Kuo-Ting Lin, Antonio Nanni, and Wen Chang

Publication:

Symposium Papers

Volume:

96

Abstract:

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.

DOI:

10.14359/2002


Document: 

SP96-04

Date: 

January 1, 1987

Author(s):

Mikael P. J. Olsen

Publication:

Symposium Papers

Volume:

96

Abstract:

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.

DOI:

10.14359/1989


Document: 

SP96

Date: 

January 1, 1987

Author(s):

Editor: Steven H. Gebler

Publication:

Symposium Papers

Volume:

96

Abstract:

SP-96 This collection of 13 papers deals exclusively with the developments and methodologies of concrete consolidation, such as equipment, consolidation of pavements, effects of compaction on flexural behavior of fiber reinforced concrete, and properties of lean concrete subjected to vibrating compaction, and much more.

DOI:

10.14359/14132


Document: 

SP96-07

Date: 

January 1, 1987

Author(s):

T. R. Harrell and G. M. Goswick

Publication:

Symposium Papers

Volume:

96

Abstract:

The permeability of a tunnel concrete lining can be significantly affected by the consolidation techniques and procedures used during a concrete placement. Both the density and the durability of the concrete will have an influence on the ultimate permeability of the concrete. Consolidation techniques and procedures that will include both external and internal vibration can be used to aid in obtaining a concrete lining, which may be characterized as slightly permeable. Techniques and procedures used for consolidation of the tunnel lining concrete for the Rocky Mountain Pumped Storage Project are presented and discussed.

DOI:

10.14359/3512


Document: 

SP96-06

Date: 

January 1, 1987

Author(s):

E. K. Schrader

Publication:

Symposium Papers

Volume:

96

Abstract:

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.

DOI:

10.14359/3510


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