International Concrete Abstracts Portal

Home > Publications > International Concrete Abstracts Portal

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: 

SP96-10

Date: 

January 1, 1987

Author(s):

Makaoto Kagaya, Hiroshi Tokuda, andMakoto Kawakami

Publication:

Symposium Papers

Volume:

96

Abstract:

Adequate consolidating condition of concrete is generally judged by experiential observation, and even in such condition the internal composition differs from one in a specified mix partially as introduced in several papers and books. Furthermore, there are a number of unclarified points regarding this phenomenon, such as the relationship between consolidating condition and internal composition in fresh state and the properties in hardened state. This study was carried out to clear the adequate consolidating condition quantitatively based on the variation degree of internal composition measured by mix analysis and of mechanical properties. The vertical distributions of air content, water-cement ratio, unit contents of materials, compressive strength, tensile strength, and modulus of elasticity were measured in the prismatic test piece casted with changing the vibrating time. A parameter to evaluate the consolidating condition was proposed from the time-dependent variations of these distributions. The adequate condition is judged from this parameter, and the method for determining this one in situ was proposed also.

DOI:

10.14359/2030

Document: 

SP96-12

Date: 

January 1, 1987

Author(s):

Mitsuyasu MashimaI

Publication:

Symposium Papers

Volume:

96

Abstract:

Fiber reinforced concrete is reinforced by a small amount of short fibers randomly dispersed into cement concrete, and this composite material is superior to normal plain concrete, with respect to flexural strength, impact resistance, and ductility. But the consistency of fiber reinforced concrete is extremely decreased by adding fiber so that, in some cases, it becomes difficult to place and mold by the ordinary method. These phenomena are observed irrespective of kinds of fibers used. The effects of compaction methods on the strength of fiber reinforced concrete with poor consistency and containing a fairly large amount of fibers were investigated. Conventional steel fiber and alkali-resistant glass fiber were used. Test specimens (10 x 10 x 60 cm) of plain and fiber reinforced concretes were compacted by external vibration with temporary or continuous compressive loading, and were tested in flexure. The mechanism of compaction effects was discussed. Test results indicate that the compaction with compressive loading increases the flexural strength of both types of fiber reinforced concretes and also does extensibility of glass fiber reinforced concrete, although the improvement is made within a certain limit of compaction loading.

DOI:

10.14359/2042

Document: 

SP96-13

Date: 

January 1, 1987

Author(s):

K. Iida and S. Horigome

Publication:

Symposium Papers

Volume:

96

Abstract:

The effect of mixing methods on compaction properties is described. A new mixing method presented divides the mixing water into two portions and adds them at different times. The concrete produced by this mixing method is called "SEC concrete" and shows low bleeding and excellent workability. Concrete employed for the experiment was lean concrete whose compactability is most important. Compactability was evaluated by means of angle of internal friction, cohesion, acceleration propagation, density, strength and modulus of elasticity. From the experimental results, the following conclusions were obtained: a) the mixing method of concrete had great effect on the compactability of produced concrete subjected to vibrating compaction; and b) double-mixed concrete showed better compactability than conventional concrete.

DOI:

10.14359/2054

Document: 

SP96-01

Date: 

January 1, 1987

Author(s):

Ken Weden

Publication:

Symposium Papers

Volume:

96

Abstract:

The lower the water content of concrete, the stronger, more durable, and less susceptible to shrinkage will be the finished product. Concrete with a low water content generally means concrete with a thick consistency or low slump. When low slump concrete is placed, it is in a honeycomb condition, consisting of mortar-coated coarse aggregate and entrapped air. The amount of entrapped air will vary with different mixes, size, and shape of forms, amount of congestion (reinforcing steel), and the method by which the concrete is placed.

DOI:

10.14359/3493

Document: 

SP96-02

Date: 

January 1, 1987

Author(s):

Dan Bonikowsky

Publication:

Symposium Papers

Volume:

96

Abstract:

Some of the problems experienced while placing concrete at the Ontario Hydro Darlington Nuclear Generating Station, located on the north shore of Lake Ontario, are described. Also presented are the novel placing methods and procedures used to overcome the placing problems to obtain the resultant quality concrete. Most of the concrete can be considered mass concrete because of its large dimensions. Placements in narrow walls have particular congestion problems and also require a slow placing rate due to formwork design limitations. Methods of achieving good consolidation and controlling time of set are described.

DOI:

10.14359/3503

123

Results Per Page