CARBONATION RESISTANCE OF SLAG MORTARS ACTIVATED BY DIFFERENT ALKALI ACTIVATORS

Year 2017, Volume: 1 Issue: 1, 1 - 4, 15.05.2017

Cahit Bilim , Cengiz Atiş

https://doi.org/10.31127/tuje.315227

Cited By: 5

Abstract

In this study, the carbonation depths of slag mortars activated by sodium silicate (water glass), sodium hydroxide and sodium carbonate were investigated and the results were compared to those of control mortar with CEM I 42.5 R normal Portland cement. In the mixture, the sand/binder ratio was 2.75 and the water/binder ratio was 0.50. Na concentrations in the mixture proportions were determined as 4%, 6%, and 8% for all the activators. For liquid sodium silicate activator, SiO₂/Na₂O ratios (Ms) of 0.75, 1, 1.25, and 1.5 were also chosen. Prismatic specimens having 40 x 40 x 160 mm dimensions were prepared from both fresh Portland cement and slag mortar mixtures for the measurements. The day after the mortar casting, the prisms were demolded and placed in a humidity cabinet at 65% ± 5 relative humidity and 22 ± 2 °C temperature. The carbonation tests of mortars were conducted at 7, 28, 90 and 180 days. It was observed that the carbonation resistance of slag mortars activated by alkalis was lower than that of control mixture with Portland cement. However, it was also seen that an increment in the Na dosage of activator improved the resistance of the activated slag mortars to carbonation.

Keywords

Carbonation, Mortar, Slag, Activator

References

• ASTM C 33 (2005). Standard specification for concrete aggregates, Annual Book of ASTM Standards, West Conshohocken, USA.
• ASTM C 989 (1994). Standard specification for ground granulated blast furnace slag for use in concrete and mortars, Annual book of ASTM Standards, West Conshohocken, USA.
• Atiş, C. D., Bilim, C., Çelik, Ö. and Karahan, O. (2009). “Influence of activator on the strength and drying shrinkage of alkali-activated slag mortar.” Construction and Building Materials, Vol. 23, No. 1, pp. 548-555.
• Bernal, S. A., Gutierrez, R. M., Provis, J. L. and Rose, V. (2010). “Effect of silicate modulus and metakaolin incorporation on the carbonation of alkali silicateactivated slags.” Cement and Concrete Research, Vol. 40, No. 6, pp. 898–907.
• Bilim, C. and Atiş, C. D. (2012). “Alkali activation of mortars containing different replacement levels of ground granulated blast furnace slag.” Construction and Building Materials, Vol. 28, No. 1, pp. 708-712.
• Bilim, C. (2016). “The fire resistance of alkali-activated slag mortars.” Çukurova University Journal of Engineering and Architecture, Vol. 31, No. 2, pp. 67-75.
• Bilim, C. (2006). The use of ground granulated blast furnace slag in cement based materials, PhD Thesis, University of Çukurova, Adana, Turkey.
• Byfors, K., Klingstedt, V., Lehtonen, P. Y. Y. and Rombern, L. (1989). “Durability of concrete made with alkali activated slag.” Proc., 3rd International Conference on Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concrete, American Concrete Institute, Trondheim, Norway, pp. 1429-1466.
• Collins, F. G. and Sanjayan, J. G. (1999). “Workability and mechanical properties of alkali activated slag concrete.” Cement and Concrete Research, Vol. 29, No.3, pp. 455-458.
• Erdoğan, T. Y. (2010). Concrete, METU Press, Ankara, Turkey.
• Neto, A. A. M., Cincotto, M. A. and Repette, W. (2008). “Drying and autogenous shrinkage of pastes and mortars with activated slag cement.” Cement and Concrete Research, Vol. 38, No. 4, pp. 565-574.
• Palacios, M. and Puertas, F. (2007). “Effect of shrinkagereducing admixtures on the properties of alkali-activated slag pastes and mortars.” Cement and Concrete Research, Vol. 37, No. 5, pp. 691-702.