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 62 Abstracts search results

Document: 

SP179

Date: 

June 1, 1998

Author(s):

Editor: V.M. Malhotra

Publication:

Symposium Papers

Volume:

179

Abstract:

This Symposium Publication contains the proceedings of the Fourth CANMET/ACI/JCI International Conference held in Tokushima, Japan, in June 1998. Sixty-two refereed papers were accepted for presentation at this conference and for this publication. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP179

DOI:

10.14359/14172


Document: 

SP179-49

Date: 

June 1, 1998

Author(s):

M. Eto, K. Maruyama and S. Ono

Publication:

Symposium Papers

Volume:

179

Abstract:

The authors have proposed a partially pre-cooling system for massive structures, such as gravity concrete dams. It is discussed in this paper how the effectiveness of the proposed method is discussed using the finite element analysis. In the ordinary pre-cooling system, pre-cooled concrete is placed in the entire region (width and depth) of a massive structure. In the proposed system , pre-cooled concrete is placed only in the surface layer. In order to evaluate the effectiveness of this system, a thermal stress analysis was conducted by the finite element method. The key parameters were the dimensions of the cooling system and cooling temperatures. The results show that the proposed system is rather effective than the conventional cooling system in terms of the thermal stress condition of massive concrete structures. In addition, the cost benefit is adequately expected.

DOI:

10.14359/10135


Document: 

SP179-34

Date: 

June 1, 1998

Author(s):

L . D’Aloia and G. Chanvillard

Publication:

Symposium Papers

Volume:

179

Abstract:

The N method of equivalent age )) is one of the currently used non-destructive testing methods of concrete strength estimation. It is based on the Arrhenius’ law, which has shown itself to be the most accurate in order to describe the influence of temperature on concrete strength development at early ages. A proper estimation is directly related to a correct determination of the Apparent Activation Energy : Ea. This is the unique parameter which characterizes the concrete mixture and which can be found in the Arrhenius’ law. The major aim of this paper is to show how calorimetric tests under semi-adiabatic conditions can be an alternative to unwieldy compressive tests procedures in order to determine Ea. The validity of the obtained Ea values has been verified by means of several mechanical tests. Moreover, the possibility of using either mortar or concrete is partially dealt with. The water to cement ratio appears to naturally be considered as a constant in proportioning an equivalent mortar. Finally, the evolution of the Apparent Activation Energy in relation to the degree of hydration is given. Hence, the widespread opinion that Ea depends on the degree of hydration is confirmed and a field of definition can be brought to the fore.

DOI:

10.14359/6061


Document: 

SP179-35

Date: 

June 1, 1998

Author(s):

A.B. Ammar, J.M. Loche and P. Dumargue

Publication:

Symposium Papers

Volume:

179

Abstract:

Penetration of aggressive ions, such as chlorides, through concrete is one of the factors which causes to the depassivation of reinforcement and therefore may shorten the service life of a reinforced concrete structure. Most research work focusing on natural or accelerated diffusion tests generally rely on the validity of Fick’s laws. In this paper, we present both a new accelerated diffusion cell and an original test operating mode. The theoretical approach is based upon the study of diffusion-migration mechanism within the pore solution. The experimental results presented here have been obtained with tests on samples of saturated mortar.

DOI:

10.14359/6062


Document: 

SP179-36

Date: 

June 1, 1998

Author(s):

H. Takenaka, M. Kakizaki, Y. Abe and M . Okada

Publication:

Symposium Papers

Volume:

179

Abstract:

A new method is proposed for the preparation of specimens of high fluidity concrete with excellent flowability and segregation resistance that can not be fully controlled by the current Japanese Industrial Standard. Procedures recommended are: (1) Slump cone should be filled in three equally divided volumes followed by rodding of 5 strokes at each layer; (2) Flow time recommended for quality control should be in 5 to 10 seconds; (3) Cylinder mold of $10 x 20 cm for the compressive strength test should be filled in two equally divided volumes followed by a rodding of five strokes at each layer, considering coarse aggregate content and stability of mechanical properties.

DOI:

10.14359/6063


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