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 39 Abstracts search results

Document: 

SP121-30

Date: 

November 1, 1990

Author(s):

George c. Hoff

Publication:

Symposium Papers

Volume:

121

Abstract:

Briefly reviews five joint industry-research programs pertaining to offshore concrete structures. These programs were sponsored by the oil and gas industry and related construction industries. These studies, conducted in both North America and Norway, included the use of high-strength, lightweight aggregate concretes in both material and structural evaluations. Selected characteristics of the high-strength, lightweight aggregate concretes used in these studies (such as ductility in reinforced concrete elements, punching shear behavior, and fatigue characteristics) are summarized. Future research needs are discussed.

DOI:

10.14359/3768


Document: 

SP121-32

Date: 

November 1, 1990

Author(s):

Min-Hong Zhang and Odd E. GjorvI

Publication:

Symposium Papers

Volume:

121

Abstract:

Pore structure, density, and strenght may vary within a wide range for different types of lightweight aggregate. Hence, not all types of lightweight aggregate are suitable for production of high-strength concrete. In the present work, the significance of various lightweight aggregates on the concrete strenght and density was studied. Twenty-eight-day compressive strengths up to 102 MPa, corresponding to a density of 1865 kg/m3, were obtained. The type of lightweight aggregate appears to be the primary factor controlling both the density and the strength. For high-strength lightweight concrete, it is difficult to predict the 28-day strengths from early strengths because of the influence of the aggregate.

DOI:

10.14359/3778


Document: 

SP121-14

Date: 

November 1, 1990

Author(s):

P. K. Mehta and P. C. Aitcin

Publication:

Symposium Papers

Volume:

121

Abstract:

During the 1980s, the use of high-strength concrete gained wide acceptance. The materials and mix proportions for making high-strength concrete are selected empirically by extensive laboratory testing since there are no accepted procedures, such as the ACI method of proportioning normal concrete mixtures. For someone who, for the first time, would like to make high-strength concrete from local materials, the problem is complicated by the fact that a variety of newly developed chemical and mineral admixtures may have to be incorporated simultaneously into the concrete mixture. The published literature has enough information on the new admixtures, but is essentially of little help in selecting the type and optimum dosage of these admixtures. In this paper, the authors have attempted to address the problem of selection of materials and mix proportions for high strength from a microstructural standpoint. Principles underlying the strength of brittle solids are discussed and important features of concrete microstructure, which influence the strength, are described. Microstructural considerations are used as a basis for the selection of materials and for establishing guidelines that are helpful in the development of a simple procedure for concrete mix proportioning.

DOI:

10.14359/2500


Document: 

SP121-15

Date: 

November 1, 1990

Author(s):

B. J. Addis and M. G. Alexander

Publication:

Symposium Papers

Volume:

121

Abstract:

Discusses the need and requirements for a method of proportioning high-strength concrete mixes. The development of the method, which is based on a well-established method used for conventional concrete, is described. Design charts are given for various stone sizes, and an example of such a chart is illustrated. Because the method is based on easily determined aggregate properties, it is suitable for any type of aggregate: crushed or naturally occurring stone and sand, and graded or single-sized stone.

DOI:

10.14359/2507


Document: 

SP121-16

Date: 

November 1, 1990

Author(s):

D. Tachibana, M. Imai, N. Yamazaki, T. Kawai, and Y. Inada

Publication:

Symposium Papers

Volume:

121

Abstract:

It is more difficult to obtain good workability and to assure high concrete compressive strengths for high-strength concretes than for lower strength concretes. Several admixtures are often used in combination to increase workability of the fresh concrete. Along these lines, two kinds of chemical admixtures and three kinds of mineral admixtures were selected for use in this study. The study was carried out to examine the effects of materials, particularly admixtures, and mix proportions on several properties of freshly mixed and hardened concrete having a compressive strength of more than 100 MPa. This paper reports on the contribution of silica fume to the workability and constructibility, with a focus on improvement of its compressive strength. It is also reported that ground granulated blast furnace slag can be utilized to improve several properties, e.g., control of thermal cracks due to the heat of cement hydration. Furthermore, slump loss characteristics, the resistance to segregation, tensile strength, modulus of elasticity, shrinkage, creep, and freeze-thaw durability, and the alkali-aggregate reactivity were tested.

DOI:

10.14359/2510


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