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International Concrete Abstracts Portal

Showing 1-5 of 11 Abstracts search results

Document: 

SP146-06

Date: 

June 1, 1994

Author(s):

H. J. Molloy, J. Jones, and T. G. Harmon

Publication:

Symposium Papers

Volume:

146

Abstract:

Presents results of a development program to improve the properties of glass fiber reinforced concrete (GFRC). The current system is composed of portland cement, silica sand, 5 percent alkali-resistant glass, curing agent (5 percent acrylic copolymer solids by weight of cement), and a water-cement ratio of 0.32. Historically, this system has resulted in loss of some ductility due to the development of calcium hydroxide, which bonds the individual filaments together in the strand, reducing their reinforcing efficiency. A new system was developed to improve the performance of the composite. This system is composed of rapid-hardening hydraulic cement, silica fume, and additives to combine with any free lime, provide enhanced workability, and a degree of retardation, using a water-cement ratio of 0.45 and 5 percent alkali-resistant glass containing 20 percent zirconium oxide. Polymer curing agents are not recommended. The durability of the system was tested using the glass industry test of immersing the product in hot water (60 C) for up to 100 days and periodically measuring the flexural strength and strain capacity using ASTM C 947-89. Analysis of the results indicates a very high retention of both flexural strength and strain capacity for the new system, after being exposed to the hot water aging test.

DOI:

10.14359/4323


Document: 

SP146-08

Date: 

June 1, 1994

Author(s):

H. Hammooud and A. E. Naaman

Publication:

Symposium Papers

Volume:

146

Abstract:

An experimental program was carried out to investigate the behavior of ferrocement bolted moment-resisting joints. Eighteen ferrocement moment joints and four control ferrocement plates were tested under third-point flexural loading. The moment joints were fabricated by joining two L-shaped ferrocement elements with bolts. The parameters investigated were the number of mesh layers, the corner distance of the first bolt, the number of bolts, and the moment modes (closing corner and opening corner modes). Results describing the load-deformation response as well as the failure mode are presented. As expected, the joints failed by premature cracking along the corner section of the L-shaped elements. The bending capacity of the joint ranged from 36 to 90 percent of that of the control plates, depending on the test parameters. The joint performance was improved by more than 50 percent when a fillet was added, and the failure crack was moved from the corner to one of the legs. The fillet was more effective for the elements subjected to the opening mode moment than the closing mode moment.

DOI:

10.14359/4590


Document: 

SP146-04

Date: 

June 1, 1994

Author(s):

N. Banthia, A. Moncef, and J. Sheng

Publication:

Symposium Papers

Volume:

146

Abstract:

Stress-strain curves in uniaxial tension are obtained for microfiber reinforced concrete composites containing high-volume fractions of carbon, steel, and polypropylene fibers, both in mono and hybrid (combination) forms. Based on these curves, considerable strengthening, toughening, and stiffening of the host matrix due to microfiber reinforcement are demonstrated. Such fiber characteristics as geometry, tensile strength, elastic modulus, and surface texture are shown to be significant. In hybrid fiber composites, different fibers appear to act as additive phases, i.e., they maintain their individual reinforcing capabilities. The potential of these composites for use in thin-sheet products and similar applications, and the need for continued research in this area, are recognized.

DOI:

10.14359/4588


Document: 

SP146-07

Date: 

June 1, 1994

Author(s):

P. Paramasivam, T. F. Fwa, and C. M. Lau

Publication:

Symposium Papers

Volume:

146

Abstract:

An analytical and experimental investigation is carried out to study the flexural behavior of concrete pavements rehabilitated with different types of overlays such as plain mortar, steel fiber mortar, and ferrocement. Explicit expressions are derived for the load-deflection characteristics based on the basic properties of constituent materials. Analytically predicted load-deflection curves are found to agree well with the experimental data. Flexural toughness indexes are also computed from the load-deflection curves. The results indicate that steel fiber mortar and ferrocement overlays show better post-cracking rigidity, a higher toughness index, and smaller crack widths compared to overlays of plain mortar or the original full-depth concrete section. They also indicate that, with a properly bonded overlay, the flexural strength of the original pavement can be achieved without distress at the interface.

DOI:

10.14359/4589


Document: 

SP146-01

Date: 

June 1, 1994

Author(s):

D. M. Gale

Publication:

Symposium Papers

Volume:

146

Abstract:

Since the turn of the century, thin-section asbestos-cement sheet and pipe products have been manufactured. Health and environmental concerns regarding the use of asbestos have led to a worldwide search for alternative fibers. Paper reviews the state of the art in using synthetic fibers to replace asbestos in fiber-cement products.

DOI:

10.14359/4614


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