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International Concrete Abstracts Portal

Showing 1-5 of 22 Abstracts search results

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: 

SP124-12

Date: 

September 1, 1990

Author(s):

I. R. K. Greig

Publication:

Symposium Papers

Volume:

124

Abstract:

The inherent light weight, toughness, low permeability, smooth surface finish and resistance to shrinkage cracking have all contributed to GFRC being an attractive alternative to traditional materials in the following areas of mining: 1) stabilization of rock tunnels by in situ spraying of thin skins; 2) construction of ventilation stopping walls both by a surface bonding technique and as a direct substitute for simple lime and sand mortars; 3) fire protection of timber packs by lightweight GFRC renders with improved adhesion and impact strength; 4) manufacture of drainage channels which are lighter in weight than their concrete counterparts and tougher than the asbestos cement alternatives; and 5) production of permanent formwork, which is lighter in weight and has a better surface finish than concrete and is much more efficient than the use of temporary shuttering.

DOI:

10.14359/3350


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: 

SP124-03

Date: 

September 1, 1990

Author(s):

T. Ando, H. Sakai, K. Takahashi, T. Hoshijima, M. Awata, and S. Oka

Publication:

Symposium Papers

Volume:

124

Abstract:

The fabrication, properties, and application of carbon fiber reinforced cement (CFRC) product made of coal tar pitch-based high-performance carbon fiber are presented. The experiments were conducted by mixing the chopped carbon fiber strands with cement and sand to obtain CFRC. The mixing test results revealed that this type of carbon fiber disperses quickly and uniformly in ordinary mortar. No special type of mixer is required. To optimize the characteristics of CFRC, experimental analysis was conducted on batches made in a mortar mixer regarding the fiber properties and mix proportion. The relationships of these parameters to the mechanical properties were examined. It was revealed that the parameters determining the apparent viscosity F (flow index) of CFRC slurries are fiber diameter í1, filament number n, specific surface area S, and fiber volume fraction Vf. It was also revealed that the parameters determining the strength of the hardened body were fiber tensile strength TS and Vf. The flexural strength of the 20 mm thick CFRC is about 3 to 4 times greater than that of plain mortar. This CFRC is also stronger and more durable than other FRC under the same conditions. High productivity, light weight, and weatherability characterize this new CFRC. These characteristics being appreciated, precast CFRC products have been increasingly used in construction in Japan. Some detailed descriptions of the practical applications are also made.

DOI:

10.14359/2239


Document: 

SP124-08

Date: 

September 1, 1990

Author(s):

Mobasher and S. P. Shah

Publication:

Symposium Papers

Volume:

124

Abstract:

Traditionally, the first cracking strain of plain matrix is used as the material property in the fiber reinforced cement-based composites. It is used to indicate the tensile strength, and thus termination of the contribution of the matrix phase. In the presence of high volume fraction of fibers, formation of the first crack does not necessarily lead to the fracture instability; thus, matrix is able to carry increasing loads. The strength of the matrix is thus dependent on the type, volume fraction, bond, and strength of the fibers. Paper investigates the tensile stress-strain response of cement paste in the presence of glass fibers. A test procedure is described that can characterize the toughening effect of various fiber types on the matrix properties.

DOI:

10.14359/2299


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