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International Concrete Abstracts Portal

Showing 1-5 of 27 Abstracts search results

Document: 

SP159-28

Date: 

February 1, 1996

Author(s):

Methi Wecharatana and John W. Liskowitz

Publication:

Symposium Papers

Volume:

159

Abstract:

Fly ash, a by-product from the coal-burning power generation process, is often used, for its pozzolanic properties and its fineness, to enhance the strength and durability of concrete and high-strength concrete. The quality assurance of fly ash is frequently questioned since its properties tend to vary depending on the source of coal, type of boiler, pulverizing equipment, and the removal efficiency of the air pollution control devices. Since fly ash is cornmonly used as one of the main components in the development of high-performance concrete, a closer look at the effects of fly ash on the properties of high-performance concrete is critical. In this study, two types of fly ash, dry and wet bottom ashes of different particle size distributions, were used. Physical and chemical properties of these fly ashes were tested and compared with the original feed fly ashes received directly from the utility. The effects of these fly ashes on the strength of concrete were studied when used as 15, 25, 35, and 50 percent cement replacement by weight of cement. The results show that fly ash, when proportioned properly, can enhance the properties of concrete. The chemical composition of fly ash of different particle size distributions varies slightly. For the same type of fly ash, the finer the particle, the higher the specific gravity. The smaller fly ash particle has a faster reactivity rate than the coarser one. The compressive strengths of several selected mixes of fly ash concrete are equal to, or higher than, the control concrete before the age of 28 days. For fly ash with large particle size distribution, the fly ash concrete reaches only 85 percent of the control concrete strength at the age of 180 days. It was also found that fly ash concrete exhibits excellent acid resistance when compared to conventional concrete.

DOI:

10.14359/16769


Document: 

SP159-07

Date: 

February 1, 1996

Author(s):

W. G. Ryan and R. J. Potter

Publication:

Symposium Papers

Volume:

159

Abstract:

Australia is a dry warm continent. The major population centres are located close to the coastline. This paper examines the predictions for future building and construction activity in Australia. Based on the physical situation, for example climate and geography, and the anticipated needs for HPC arising from the forecast trends in construction activity it tries to forecast the research needs for HPC in Australia. It also endeavours to assign priorities for these research needs in terms of the size of the market likely to be affected.

DOI:

10.14359/10051


Document: 

SP159-08

Date: 

February 1, 1996

Author(s):

B. Vijaya Ranigan

Publication:

Symposium Papers

Volume:

159

Abstract:

High Performance/High Strength Concrete (HPC/HSC) has been used in a number of projects in Australia. Research on HPC/HSC is currently in progress in a number of centers around the country. The author and his research team at Curtin University have been engaged in research on the behavior and the strength of HPC/HSC structural members for the past five years. The research comprises experimental and analytical studies on columns under eccentric compression, structural walls subjected to horizontal and vertical loads, shear strength of beams, bond strength and bar splice lengths, and concrete-filled steel tubular composite columns. The test specimens were made using the HPC/HSC supplied by a commercial ready mix plan in Perth, Western Australia. The research was funded by the Australian Research Council Grants and by the industry. This paper summarizes the application of HPC/HSC in Australia, the current research at Curtin, and the future research needs.

DOI:

10.14359/1397


Document: 

SP159-04

Date: 

February 1, 1996

Author(s):

Ekasit Limsuwan

Publication:

Symposium Papers

Volume:

159

Abstract:

Flowable concrete has been used for a long time in Thailand and has been known as tremy concrete for bored pile construction. For this type of concrete, strength may be less important in early development, but workability must satisfy the performance in construction. In the second stage of development, research has concentrated on high strength concrete. Even though higher strengths have been achieved, workability of the concrete may be slightly poor. Several studies have emphasized utilization of concrete here high strength can be an advantage. The structural members were both reinforced concrete and prestressed concrete; and the emphasis was placed on flexure, shear, and compression. In recent development, both workability in the fresh state and strengths in the hardened states have been considered so as to satisfy the performance in workability, strengths, serviceability, and durability. Efforts have been concentrated on constituent materials for high performance concrete, mix proportions, and concrete properties. Satisfactory structural behaviors for compression, flexure, and shear in reinforced and prestressed concrete members have been reported. Various developments to suit particular applications such as bored pile, mass concrete, structural concrete, and durable concrete have been made for the construction industry. Demands of HPC are growing, further development and utilization are expected.

DOI:

10.14359/1592


Document: 

SP159-16

Date: 

February 1, 1996

Author(s):

L. Elfgren, G. Fagerlund, and A. Skarendahl

Publication:

Symposium Papers

Volume:

159

Abstract:

A consortium of six companies and two governmental research funding organizations are carrying out a six-year research and development program on high performance concrete in Sweden. In mid-94, half the program time was completed. The program focused on research directed towards the understanding of mechanisms and subsequent modeling and experimental verification. It also included application and oriented research aiming at the establishment of technical relationships. This should further lead to practical recommendations and guidance for use in specific projects or product and process development within the industry. The program was divided into 17 different subprojects that were grouped under the headings of materials, production technique, and structures. The fields of research were selected following an evaluation of the possibilities offered by dense, low w/c ratio cementitious systems in improving performance, but at the same time the potential risks when using these systems were addressed. An evaluation on possible application areas resulted in the study of certain aspects of structural behavior. The research was carried out at eight different research entities in Sweden as well as by research and development personnel from the consortium participants. The work was done in laboratories as well as in situ.

DOI:

10.14359/1599


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