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International Concrete Abstracts Portal

Showing 1-5 of 18 Abstracts search results

Document: 

SP89-12

Date: 

December 1, 1985

Author(s):

Y. Ohama, K. Demura, and R. Muranishi

Publication:

Symposium Papers

Volume:

89

Abstract:

In the past a few years, greater interest has been focussed on the use of silica fume as a concrete admixture, which is a by-product in the manufacturing process of ferrosilicon and metallic silicon. The purpose of this study is to find appro-priate process conditions for developing superhigh strength concrete by the application of both silica fume addition and polymer impregnation. Base concrete was mixed by use of the silica fume and polyalkyl aryl sulfonate-type water-reducing agent, and cured in autoclave or hot water. The cured base concrete was dried, and impregnated with polymethyl methacrylate by thermal polymerization in hot water. The strength properties of such superhigh strength concrete were tested. The reproduci-bility of its strength development was examined. It is concluded that superhigh strength concrete having a compressive strength of 2370 to 2600 kg/cm2 is obtained by the above process with good reproducibility.

DOI:

10.14359/6251


Document: 

SP89-15

Date: 

December 1, 1985

Author(s):

R. John Craig, Ishac Kafrouni, Jean Souaid, Sitaram Mahadev, and H. Wayne Valentine

Publication:

Symposium Papers

Volume:

89

Abstract:

The testing program of reinforced concrete joints con-sisted of six beam column joints with varying strength cementing agents in the joint region: 1) normal strength concrete (fc' = 4,000 psi); 2) high strength concrete (fc' = 10,000 psi); and 3) polymer concrete (fc' = 12,000 psi). Half of these joints con-tained l-l/2 percent by volume of hooked end fibers. The polymer used in the joint region was Sika Stix 350. The fibers used were dramix fibers (30 mm. long by .50 mm. in diameter). From the test series on joints of this investigation, information on the following will be described: strength, ductility, energy absorp-tion and dissipation, mechanisms of failure, and mechanisms of stiffness and energy dissipation under cyclic loading. From the analysis of the results, it can be concluded that the polymer concrete used in the joint region provided: 1) better bond; 2) better confinement of the joint region; 3) a stiffer mem-ber; 4) a higher moment capacity; 5) higher shear strength; 6) more ductility; 7) far less cracking; and 8) significant improve-ment in the energy dissipation capacity than did the 4,000 psi and 10,000 psi portland cement concrete used in the joint area. The addition of fibers helped to strengthen the joint region, and improve the energy absorption and dissipation capacity of the joints with normal and high strength concrete. Also, the addi-tion of fibers to the beam column with polymer in the joint re-gion made made the joint area act elastically while the inelastic region was formed a distance 10 inches from the face of the col-umn in the normal strength concrete beam. The benefits and disadvantages of using a polymer concrete instead of high strength or normal concrete in seismic construc-tion of a joint will be described.

DOI:

10.14359/6254


Document: 

SP89-09

Date: 

December 1, 1985

Author(s):

Yu Feixiong and Huang Yiun-yuan

Publication:

Symposium Papers

Volume:

89

Abstract:

A PIG of 2400 kg/cm 2 compressive strength is obtained by use of an ordinary cement mortar of 600 kg/cm2 compressive strength (W/C = 0.5, S/C = 2.5 : 1 by wt.) as matrix and MMA as its impregnant with impregnation and thermal catalytic polymerization under high pressure up to 200 atmospheres. Using the same materials, the compressive strength of the PIC obtained with ordinary impregnation is only 1600 kg/cm2. The polymer loadings of the former and the latter PIC are 9.2% and 7.5% respectively. The following contribute to the super-high compressive strength of this PIC: (1) Minimizing the effect of residural air; (2) Overcoming the airblock effect due to ink-bottle-shaped pores during impregnation; (3) Reducing the effect of shrinkage of impregnant during polymerization; and (4) Increasing the interfacial area and adhesive power between matrix and polymer.

DOI:

10.14359/6248


Document: 

SP89-02

Date: 

December 1, 1985

Author(s):

Albert 0. Kaeding

Publication:

Symposium Papers

Volume:

89

Abstract:

Processes are described for centrifugally applying polymer concrete (PC) liner to straight pipe, for casting the PC liner in pipe fittings, and for closure of field joints. Physical properties of the PC liner materials were measured. Compressive strengths of up to 165.8 MPa (24,045 psi) and splitting tensile strengths of 23.5 MPa (3408 psi) were measured at ambient temperature. Compressive strengths of 24 MPa (3490 psi) and splitting tensile strengths of 2.5 MPa (366 psi) were measured at about 150°C (302OF). Cost of piping a geothermal plant with PC and PC-lined steel pipe is calculated to be $1.21 million, which compares favorably with a similar plant piped with alloy steel piping at a cost of $1.33 million. Life-cycle cost analysis indicates that the cost of PC-lined steel pipe would be 83% of that of carbon steel pipe over a 20 year plant operating life.

DOI:

10.14359/6241


Document: 

SP89-16

Date: 

December 1, 1985

Author(s):

Y. Ohama and K. Shiroishida

Publication:

Symposium Papers

Volume:

89

Abstract:

Recently powdered emulsions of improved quality have, been developed and commercialized as cement modifiers. Mixed in a powder form with cement mortars, they are re-emulsified and modify the mortars. The purpose of this study is to evaluate the quality of the commercial powdered emulsions for cement modifiers. Polymer-modified mortars using powdered emulsions were prepared with variation in polymer-cement ratio, and tested for strength, adhesion, waterproofness, length change and water resistance. Their properties were also compared with those of ordinary polymer-modified mortar using styrene-butadiene rubber latex. It is concluded from the test results that the powdered emulsion- modified mortars can be used in the same manner as ordinary polymer-modified mortar in practical applications, in consideration of their drying shrinkage.

DOI:

10.14359/6255


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