ABOUT THE 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.

International Concrete Abstracts Portal

Showing 1-5 of 63 Abstracts search results

Document: 

SP153

Date: 

June 1, 1995

Author(s):

Editor: V.M. Malhotra

Publication:

Symposium Papers

Volume:

153

Abstract:

SP-153 In 1995, CANMET, in association with ACI, U.S.A. Electric Power Research Institute, Canadian Electrical Association, and several other organizations in Canada and the United States, sponsered the Fifth International Conference on fly ash, ferrous and nonferrous slags, and silica fume was held. The two volume proceedings of the Fifth CANMET/ACI Conference contains 62 papers from 23 countries.

DOI:

10.14359/14193


Document: 

SP153-41

Date: 

June 1, 1995

Author(s):

H. Fujiwara, E. Sawada, and Y. Ishikawa

Publication:

Symposium Papers

Volume:

153

Abstract:

The increasing construction of high-rise buildings in recent years had led to a demand for lightweight, high-strength concrete. In this study, the compositions of the matrix and the air void structure of aerated mortar containing silica fume were investigated as the basis for manufacturing lightweight, high-strength concrete. Mortars made with cement containing silica fume and fine or ultra-fine silica stone powder, having a particle size between that of cement and silica fume, were tested; the properties of cement paste in fresh and hardened conditions were improved. The compressive strength and the air void structure of prefoamed aerated mortars were determined and their relationship studied. Based on the results, it was confirmed that lightweight, high-strength concrete could be made with an effective combination of aerated mortar containing silica fume and lightweight coarse aggregate.

DOI:

10.14359/1141


Document: 

SP153-37

Date: 

June 1, 1995

Author(s):

E. H. Atlassi

Publication:

Symposium Papers

Volume:

153

Abstract:

The most common way of estimating the degree of hydration of cement in practice has been to measure the Nonevaporable water content (W n) using the relation W n = 0.25 * C. However, when silica fume is incorporated in a mixture, some of the nonevaporable water is converted to evaporable water. More specifically, the water originally bound in the Ca(OH) 2, which reacts with the amorphous silica, is released in a polymerization process. This was shown in a study of mature cement-silica fume systems in which a new quantitative thermogravimetric method was used. Thus, for the same degree of hydration of the cement, the total nonevaporable water content is lower in a mixture with reacted silica fume than in one without. Moreover, the degree of hydration of the cement is slightly increased when moderate amounts of silica fume are added, provided sufficient water is present in the pore system, either by water curing or a high initial water-cement ratio. In mixtures with low w/c, the faster self-desiccation and the reduced permeability caused by silica additions affect the moisture state in a larger specimen (even if it is water cured) and, consequently, the degree of hydration of the cement.

DOI:

10.14359/1028


Document: 

SP153-32

Date: 

June 1, 1995

Author(s):

B. Fournier, W. S. Langley, and V. M. Malhotra

Publication:

Symposium Papers

Volume:

153

Abstract:

Three reactive aggregates from New Brunswick, Canada, a greywacke, a gneiss, and a meta-volcanic rock were evaluated for their potential alkali reactivity (AAR) in concrete mixtures incorporating 420 kg/m 3 of cementitious materials. The concrete mixtures consisted of the control made with CSA Type 10 low- and high-alkali cements and mixtures incorporating ASTM Class F fly ash at 20, 30, and 56 percent replacement levels of the high-alkali cement. The susceptibility of the concretes to AAR was evaluated by casting test prisms and subjecting these to various accelerated curing conditions in the laboratory. For comparison purposes, mortar bars were also made and tested according to the ASTM C 1260-94 Accelerated Mortar Bar Test procedure. The AAR concrete prism tests performed in this study have shown that none of the test prisms cast from concrete mixtures incorporating 20, 30, and 56 percent fly ash showed significant expansion after two years of testing at 38 C and relative humidity >95 percent. These results were in good accordance with those obtained in the accelerated mortar bar test. Some alkaline immersion tests results would indicate, however, that concrete incorporating 20 percent fly ash might not offer adequate protection against potential deleterious expansions with highly reactive aggregates.

DOI:

10.14359/1089


Document: 

SP153-04

Date: 

June 1, 1995

Author(s):

H. A. W. Cornelissen, R. E. Hellewaard and J. L. J. Vissers

Publication:

Symposium Papers

Volume:

153

Abstract:

In the present research project, fly ash was mechanically processed to 1 to 5 micron particle size. Mortars and concretes were made from these processed fly ashes. In this paper, the results of the micronized fly ash are compared to the results gained with air classified fly ash, silica fume, and blends. It was found that using ground fly ashes, very fluid mixtures can be produced with excellent strength and durability properties. Because of the growing interest in ultra-fine supplementary cementing materials (SCM's) for high-performance concrete, there is a need to find ways to micronize fly ashes in an economical way.

DOI:

10.14359/1064


12345...>>

Results Per Page