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International Concrete Abstracts Portal

Showing 1-2 of 2 Abstracts search results

Document: 

SP233-01

Date: 

March 9, 2006

Author(s):

C.R. Cornman, H. Koyata, and A.A. Jeknavorian

Publication:

Special Publication

Volume:

233

Abstract:

The challenge in producing successful self-consolidating concrete (SCC) is based on consistently achieving high flow and high stability. The foundation of high quality SCC production is the suitability of the underlying materials and a mixture design that is optimized for those materials and the application. Not all applications require relatively high slump flows in the range of 28-30 inches (700-750mm), where control measures need to be especially well managed. Furthermore, even the best mixture designs can have stability limitations. To assure that SCC applications proceed with minimal difficulties, the concrete producer must anticipate variations in materials and production operations through effective quality control procedures. Changes in cement reactivity, aggregate properties (gradation, shape, and water demand), free moisture, and extra sources of moisture that may be present, for instance, in the truck, and the mixing process need to be carefully monitored. This paper will discuss specific examples that demonstrate best practices in mixture design, QA/QC, and production techniques.

10.14359/15819


Document: 

CI2107Hwang

Date: 

July 1, 1999

Author(s):

Chao-lung Hwang, Huo-young Wang, and Yeong-nain Sheen

Publication:

Concrete International

Volume:

21

Issue:

7

Abstract:

In 1996, for the construction of the 85-story T&C Tower in Kaohsiung, Taiwan, the fifth tallest building in the world at 347.6 m (1140 ft) at that time, high-performance concrete (HPC) with a compressive strength of 56 MPa (8100 psi) was pumped into steel columns up to 60 stories. Before formal concrete construction, the drum test and mock-up test were used to gather information to learn troubleshooting techniques related to high viscous HPC, such as high ambient temperature, long transportation time, and pumping difficulties (long pipeline and high pumping pressure). Research results prove that high slump and slump flow were needed to reduce the amount of air bubbles under diaphragm of the steel column. During the learning process, several kinds of checklists were built up, and a quality assurance program was established. Owing to the system, the variance of HPC materials was reduced. Hence, good quality and high stability of HPC is important to guarantee smooth pumping, and to increase construction efficiency and long-term stability.


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