USE OF ADMIXTURES FOR REDUCING AUTOGENOUS SHRINKAGE OF CONCRETE
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Published:2002
S Subramaniaii, S Manohar, V Mallikarjun, Bh Nagabhusana Rao, N Srinivasan, 2002. "USE OF ADMIXTURES FOR REDUCING AUTOGENOUS SHRINKAGE OF CONCRETE", Innovations and Developments In Concrete Materials And Construction: Proceedings of the International Conference held at the University of Dundee, Scotland, UK on 9–11 September 2002, Ravindra K. Dhir, Peter C. Hewlett, Laszlo J. Csetenyi
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Autogenous shrinkage of concrete is of concern because of the low water binder ratios and high powder contents used in high performance concrete. This paper describes an investigation carried out to study the effect of supplementary cementitious materials on the autogenous shrinkage of concretes with low water to binder ratios. The investigation covers the effect of four tensio active chemicals in reducing the potential for autogenous shrinkage of such concrete. The results indicate that the parameter based on paste / aggregate ratio is a good indicator over the potential of autogenous shrinkage of concrete. Use of fly ash and Metakaolin decrease the autogenous shrinkage, whereas blast furnace slag and microsilica may give rise to increased levels. Out of the four shrinkage reducing admixtures investigated, ethyl propyl polyoxy ethylene ether at a dosage of 0.025% by weight of cementitious materials is found to be effective and it reduces the autogenous shrinkage by 40%. However, the compressive strength, particularly at early ages, may be reduced and this must be taken into account.
INTRODUCTION
RESEARCH SIGNIFICANCE
MECHANISM OF AUTOGENOUS SHRINKAGE
EXPERIMENTAL PROGRAMME
PLAN OF EXPERIMENTS
RESULTS OF PRELIMINARY TRIALS
RESULTS OF CORE INVESTIGATIONS
CONFIRMATORY EXPERIMENTS
CONCLUSIONS
REFERENCES
