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 56 Abstracts search results

Document: 

SP138-02

Date: 

September 1, 1993

Author(s):

Rajan Sen, Daniel Mariscal, and Mohsen Shahawy

Publication:

Symposium Papers

Volume:

138

Abstract:

A comprehensive durability study of S-2 glass-epoxy pretensioned beams exposed to wet-dry cycles in 15 percent salt solution indicated a complete loss of effectiveness within 3 to 9 months of exposure. Paper presents results of subsequent follow-up investigations to identify the cause of this deterioration and also to examine practical measures that could be used to prevent its occurrence. The analysis of the test results suggests that the most likely cause of failure was diffusion of hydroxyl ions from the concrete pore solution through the resin. This is supported by SEM micrographs of the failed beam. While these conclusions are valid only for the S-2 resin, diffusion is also likely to be a characteristic of other types of resins, e.g., vinylesters and polyesters. This makes long-term protection of glass fibers in concrete problematic.

DOI:

10.14359/3857


Document: 

SP138-03

Date: 

September 1, 1993

Author(s):

K. Mukae, S. Kumagai, H. Nakai, and H. Asai

Publication:

Symposium Papers

Volume:

138

Abstract:

Bond characteristics of FRP rod and concrete after freezing and thawing deterioration

DOI:

10.14359/3858


Document: 

SP138-07

Date: 

September 1, 1993

Author(s):

Taketo Uomoto and Hosam Hosam Hodsam

Publication:

Symposium Papers

Volume:

138

Abstract:

The mechanical behavior and tensile strength of three kinds of FRP rods were investigated experimentally. For each material, three different fiber volume fractions were tested in axial tension. The stress-strain relationships and strength distributions were obtained. The results were correlated to the behavior and strength of the basic strengthening elements, fibers, as determined experimentally. This yielded the possibility of predicting rod modulus, but not strength, from those fibers. The strength distributions showed a shift that is not generally proportional to rod fiber content. Investigation of this phenomenon, through stress analysis at the grips and inspection of failed rods, assured the change of rod failure modes for different fiber contents. The effect of grips could lead to one of two shear failure modes instead of tension mode. Therefore, an apparent strength reduction was observed. In view of rod properties, appropriate design of the gripping system is needed to obtain the best performance of the rods.

DOI:

10.14359/3859


Document: 

SP138-17

Date: 

September 1, 1993

Author(s):

Takashi Yamada, Kanji Yamada, and Kenji Kubomura

Publication:

Symposium Papers

Volume:

138

Abstract:

The potential of using pitch-based high-modulus carbon fiber was investigated as a reinforcement in cementitious composites for structurally reinforced concrete members. For this purpose, effects of carbon fiber mechanical properties on the mechanical properties of carbon fiber reinforced cementitious composites were studied through the three-point flexural test by using several pitch-based high-modulus carbon fiber rods of varying fiber moduli and strengths. For the specimens with a fiber volume fraction larger than the critical volume fraction, the flexural strength is found to exceed the mortar mix strength and is linearly proportional to the sum of all rod strengths, and the flexural modulus after matrix cracking is found to also be linearly proportional to the sum of all rod stiffnesses. 111-493

DOI:

10.14359/3860


Document: 

SP138-47

Date: 

September 1, 1993

Author(s):

Tomoya Nagasaka, Hiroshi Fukuyama, and Masamaru Tanigaki

Publication:

Symposium Papers

Volume:

138

Abstract:

An experimental investigation was conducted to study the shear performance of concrete beams with bar-shaped FRP reinforcement. The 35 half-scale beams were subjected to monotonically increased shear force up to ultimate capacity. The principal variables were type and reinforcement ratio of stirrup and concrete strength. The beams with FRP stirrups failed due to either breaking of the curved stirrup sections or crushing of a diagonal strut. The former failure mode was excessively brittle and more undesirable than the latter. The ultimate shear capacity increased with increasing the content of FRP stirrup, and was not so remarkably affected by the type of stirrup, although the FRP stirrups without yielding did not so effectively carry the shear force as conventional steel stirrups. Under the same stirrups, the shear capacity of the beams flexurally reinforced with FRP bars was smaller than that of the beams with steel bars. Further, it was observed that the ultimate shear capacity of beams with FRP stirrups can be fairly well estimated by substituting the tensile strength of curved sections of stirrup for the yield strength in Arakawa's formula.

DOI:

10.14359/4138


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