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International Concrete Abstracts Portal

Showing 1-5 of 22 Abstracts search results

Document: 

SP124-01

Date: 

September 1, 1990

Author(s):

Kenneth D. Vinson and James L. Daniel

Publication:

Symposium Papers

Volume:

124

Abstract:

Describes the investigation of a new range of cellulose fibers suited to the reinforcement of a portland cement matrix. This investigation indicated that fibers selectively derived from high-density summerwood are better suited for reinforcement than is the unmodified pulp that contains a large measure of fibers derived from springwood as well as summerwood. Another cellulose fiber material, termed expanded fiber because of its finely fibrillated microstructure, was indicated to have potential as a processing aid. Expanded fiber displayed excellent suspending and retention properties and imparted relatively high uncracked strength to finished composites. Overall, substantial performance differences were observed comparing, tests on wet versus dry specimens and the long-term durability was not evaluated. Despite these limitations, flexural stress/strain performance of the cellulose reinforced composites compared quite well to asbestos and glass fiber reinforced composites. The cellulose composites had substantially more ductility than asbestos cement; in this regard, the load-deflection curve was similar to glass reinforced cement.

DOI:

10.14359/2230


Document: 

SP124-09

Date: 

September 1, 1990

Author(s):

R. G. Oesterle, D. M. Schultz an J. D. Glikin

Publication:

Symposium Papers

Volume:

124

Abstract:

Thin-walled glass fiber reinforced concrete (GFRC) panels are used as facade systems for commercial structures. Wind load and gravity load are primary load cases typically considered in panel design. However, since the GFRC skin is relatively thin, it responds rapidly to thermal and moisture variations. Therefore, minimizing restraint of the GFRC skin movement under varying environmental conditions and/or determination of stresses resulting from restrained movement are also primary considerations in GFRC facade panel design. Paper addresses concepts for design of GFRC panels including material behavior, design strengths, and loading combinations. Discussions of load conditions and recommended design considerations are presented for the effects of manufacturing, handling, and erection loading, gravity loading, wind loading, and loading due to external and internal restraint of moisture and thermal movements. Paper is based on the authors' experiences during their involvement in the design process for several new GFRC installations along with observations made and lessons learned in evaluation of GFRC facade failures

DOI:

10.14359/3134


Document: 

SP124-19

Date: 

September 1, 1990

Author(s):

T. S. Krishnamoorthy, V. S. Parameswaran, M. Neelamegam, and K. Balasubramanian

Publication:

Symposium Papers

Volume:

124

Abstract:

Precast thin ferrocement planks have replaced wood for a variety of applications. Present knowledge about joining them using steel bolts or similar means is very limited. While bolted connections are commonly employed in steel construction, their suitability for connecting precast reinforced concrete or ferrocement elements is yet to be fully investigated, particularly when subjected to both bending and direct tension. A series of tests were carried out at the Structural Engineering Research Centre, Madras, India, on precast ferrocement planks connected together using steel bolts for transferring tension and flexural moment

DOI:

10.14359/3356


Document: 

SP124-04

Date: 

September 1, 1990

Author(s):

David M. Gale, Ashok H. Shah, and P. Balaguru

Publication:

Symposium Papers

Volume:

124

Abstract:

Researchers have developed a new form of fibrous polyethylene to replace asbestos fibers in asbestos-cement composites. This very fine, short, molecularly oriented polyethylene pulp was tested in cement at various levels of incorporation and in combination with other fibers. Most of the initial investigation was focused on the pure cement matrix normally used for asbestos-cement products; however, this paper includes preliminary work with cast cement-mortar matrixes. The polyethylene pulp can be used effectively for reinforcing cement. Flexural strengths can be increased by more than 200 percent. The pulp induces excellent ductility. Accelerated aging studies indicate that the pulp is durable in alkaline cement matrixes.

DOI:

10.14359/2256


Document: 

SP124-05

Date: 

September 1, 1990

Author(s):

Parviz Soroushian, Ziad Bayasi, and Ataullah Khan

Publication:

Symposium Papers

Volume:

124

Abstract:

A cementitious matrix capable of dispersing fibers using conventional mixing techniques was developed. The effects of reinforcing this matrix with different volume fractions (0 to 2 percent) of aramid fibers ranging in length from 1/8 to 1/2 in. (3 to 12.7 mm) on the composite material performance in the fresh and hardened states were assessed experimentally. The effects of matrix mix proportions on the fibrous material properties were also investigated. The test data generated in this study indicated that improvements in strength and toughness characteristics of cementitious materials can be achieved through aramid fiber reinforcement, with no need to use specialized manufacturing techniques.

DOI:

10.14359/2267


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