The utilization of supplementary cementitious materials is well accepted because of the several improvements possible in the concrete composites and due to the overall economy. The present paper is an effort to quantify the 28-day cementitious efficiency of ground granulated blast furnace slag (GGBS) in concrete at the various replacement levels. It was observed that this overall strength efficiency of GGBS concretes can also be defined through a procedure adopted earlier for other cementitious materials like fly ash and silica fume. The overall strength efficiency was found to be a combination of general efficiency factor, depending on the age and a percentage efficiency factor, depending upon the percentage of replacement as was the case with a few other cementitious materials like fly ash and silica fume reported earlier. This evaluation makes it possible to design GGBS concretes for a desired strength at any given percentage of replacement.

K. Ganesh Babu

Composition effects

Compressive strength

Granular materials

Slags

GROUND GRANULATED BLAST FURNACE SLAGS (GGBS)

Concretes

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Efficiency of GGBS in concrete

Cement and Concrete Research

Ground granulated blast furnace slag (GGBFS), a by-product of the steel manufacturing industry, being used as an effective partial cement replacement material, has already been proven to improve several performance characteristics of concrete. The reactivity of GGBFS has been found to depend on the properties of slag, which vary with the source of slag, type of raw material used, method and the rate of cooling. The present work aims at bringing out a novel relationship between the Hydraulic Index (HI) of slag at 7 and 28 days (HI7 and HI28) and the influencing properties of slag, namely, glass content, fineness and chemical composition by employing multiple regression analysis on 37 slag samples from various sources. HI7 and HI28, thus obtained, have been mapped onto a Slag Activity Index (SAI) plot, giving an indication of the ranges of strength of slag. © 2003 Elsevier Science Ltd. All rights reserved.

Investigation of hydraulic activity of ground granulated blast furnace slag in concrete

The use of silica fume as a mineral admixture for the production of high strength high performance concretes is gaining importance in recent years. The present paper is an effort towards a better understanding of the efficiency of silica fume in concrete. It was observed from an evaluation of the data available in literature that the efficiency of SF in concrete was not a constant at all percentages of replacement. It was proposed that the "overall efficiency factor" of SF can be assessed in two separate parts, the "general efficiency factor" - a constant at all the percentages of I replacement and the "percentage efficiency factor" - varying with the replacement percentage. A comparison of the efficiencies obtained from the earlier data with studies on a "Lower Grade Silica Fume" in the laboratory show that the proposed values of efficiency are of lower bound and it is possible to achieve even higher efficiencies with proper mix proportioning. © 1995.

Efficiency of silica fume in concrete

Earlier efforts towards an understanding of the efficiency of fly ash in concrete has led to the introduction of rational methods. Based on the results available on some of the more recent pulverised fuel ashes, the authors evaluated the efficiency of fly ash in concrete over a wide range of percentage replacements (15-75%). It was clearly shown that the overall efficiency of fly ash cannot be adequately predicted using a single efficiency factor at all percentages of replacements. The overall efficiency factor (k) has been evaluated at all percentages of replacements considering the general efficiency factor (ke) and the percentage efficiency factor (kp). This study resulted in a quantitative assessment of the behaviour of fly ash in concrete, especially for the 28 day compressive strength at different percentages of replacement. © 1994.

Journal	Data powered by TypesetCement and Concrete Research
Publisher	Data powered by TypesetElsevier Science Ltd, Exeter
ISSN	00088846
Open Access	No