Shrinkage of the alkali-activated slag mortars containing alternative activator

conference paper

English

The paper deals with the experimental determination of the shrinkage process of the alkali-activated slag mortars (AASM). Two mortars which differed especially in the type of used aggregate were mixed for the experiment. The slag-aggregate ratio was 1:3 for both mortars. The waste sludge, obtained from the water glass production, was used as an activator. The desired workability of the fresh mixtures was reached by addition of water. Because of the high water demand of waste sludge, the water-slag coefficient (w/s) was relatively high – 0.98 for the mortar with the natural sand and 0.73 for the mortar with the standard sand. All test specimens were removed from the moulds at the age of 24 hours and left to dry freely in the laboratory conditions with a temperature of 21 ± 2°C and relative humidity of 50 ± 10% during the whole time of measurement. The results show that AASMs which contain waste sludge exhibit rapid shrinkage with a high magnitude independent on the type of aggregate. During the first 40 hours of ageing, both mortars reached approx. 50% of the final value of shrinkage. The high shrinkage was strengthened by a high w/s coefficient needed to maintain the workability of the fresh mixtures.

shrinkage, mortar, slag, alkali activation

KUCHARCZYKOVÁ, B.; BÍLEK, V.; ŠIMONOVÁ, H.

5. 12. 2019

IOP Publishing Ltd.

Bristol

1757-899X

IOP Conference Series: Materials Science and Engineering

660

1

United Kingdom of Great Britain and Northern Ireland

1

7

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