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International Concrete Abstracts Portal

Showing 1-5 of 34 Abstracts search results

Document: 

SP119-09

Date: 

September 1, 1989

Author(s):

E. Hanna, K. Luke, D. Perraton, and P.-C. Aitcin

Publication:

Symposium Papers

Volume:

119

Abstract:

To study the interaction between either a given superplasticizer with different portland cements or the interaction of different superplasticizers on a given portland cement, a special apparatus called RHEOPUMP was developed. It is possible with this app

DOI:

10.14359/2462


Document: 

SP119-26

Date: 

September 1, 1989

Author(s):

M. Kawakami, S. Wada, and K. Suzukawa

Publication:

Symposium Papers

Volume:

119

Abstract:

Describes the effect of superplasticizer (SP) and air-entraining water-reducing admixture (AE-WRA) on spread, turbidity, pH, flowability, setting time, and compressive strength of colloidal underwater concrete. In summary, the studies resulted in the following conclusions: Spread was affected considerably by the SP and was not controlled by the AE-WRA; turbidity was affected by both SP and AE-WRA when the apparent viscosity of the concrete was low; pH was affected somewhat by the SP and AE-WRA; flowability was affected considerably by the SP; setting time was affected by both SP and AE-WRA when water-cement ratio was lower; the strength of underwater concrete was not affected by SP or AE-WRA amounts.

DOI:

10.14359/2550


Document: 

SP119-08

Date: 

September 1, 1989

Author(s):

Y. Sekiguchi, T. Okada, and T. Ukigai

Publication:

Symposium Papers

Volume:

119

Abstract:

Effects of calcium polystyrene sulfonate-based superplasticizer (SP.PSS-Ca) and sodium b-naphthalene sulfonate-based superplasticizer (SP.NSF-Na) on concrete behavior were studied. The SP.PSS-Ca does not contain sodium and potassium (Na, K), the cause of alkali-aggregate reaction, and hence is less harmful than SP.NSF-Na. SP.PSS-Ca gave a larger increase of slump, smaller increase of air content, smaller air loss, and slump loss than SP.NSF-Na at the same dosage. The dosage of SP.PSS-Ca was 70 percent of that required for SP.NSF-Na to obtain the required slump. SP.PSS-Ca did not increase the air content to flowing concrete of base concrete, but SP.NSF-Na increased it. SP.PSS-Ca showed lower air loss and slump loss (0.6 percent, 3.5 cm/90 min) than SP.NSF-Na (2.0 percent, 7.0 cm/90 min). Other properties such as bleeding, setting time, and compressive strength were similar with SP.PSS-Ca and SP.NSF-Na. Thus SP.PSS-Ca can be considered to have better properties as a superplasticizer than SP.NSF-Na.

DOI:

10.14359/2437


Document: 

SP119-03

Date: 

September 1, 1989

Author(s):

A. J. Ulshizer, J. J. Ucciferro and G. E. Gray

Publication:

Symposium Papers

Volume:

119

Abstract:

Describes the expanded achievements possible in concrete placements with the aid of superplasticizers and identifies the importance of preplacement testing and planning to determine structural performance and placing characteristics and limitations. Diff

DOI:

10.14359/2399


Document: 

SP119-28

Date: 

September 1, 1989

Author(s):

J. W. Brook and R. J. Ryan

Publication:

Symposium Papers

Volume:

119

Abstract:

An innovative chemical admixture has been developed which is effective between -7 and 35 C (20 and 95 F) and which is useful year-round. High dosage levels of 3910 to 5860 ml/100 kg (60 to 90 oz/cwt) of cement help to prevent concrete from freezing in cold weather at -7 to 0 C (20 to 32 F) ambient temperature while providing required set time and strength acceleration. Lower dosage rates of up to 1955 ml/100 kg (30 oz/cwt) of cement provide better acceleration at more moderate ambient temperatures. It provides the ability to better control set time of concrete that is retarded because cement has been replaced by fly ash. A variety of tests have shown that the admixture does not initiate corrosion of steel reinforcement embedded in concrete. Laboratory data is presented that demonstrates that the new chemical admixture provides strong, durable concrete with accelerated set, lower water demand, increased strength development, and will help prevent freezing in cold environments as low as -7 C (20 F) ambient temperature when properly air entrained. The use of warm concrete mix components and curing conditions normally practiced in the industry and recommended by ACI in newly published guidelines for cold weather concreting are not entirely necessary. Finally, use of this all-temperature accelerating admixture provides savings in both concreting cost and time.

DOI:

10.14359/2556


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