Microstructural Investigation of Carbonation of Calcium Silicate Hydrate in Hydrated Cement Paste

Abstract:

Carbonation is one of the most common degradation reactions of concrete which greatly shortens the service life of steel-reinforced concrete structure. The carbonation of synthetic calcium silicate hydration derived from hydrated cement paste is investigated with microstructural characterization method including scanning electron microscopy, X-ray diffraction analysis, coupled TG-DSC analysis and Fourier transform infrared spectroscopy. The changes in the morphology, mineral composition and polymerization degree of the calcium silicate gel before and after the carbonation are investigated. The major finding of the research includes that the C-S-H collapses during the carbonation reaction, which actually densifies the microstructure. The major hydration product is calcite. The carbonation resistance of C-S-H is enhanced with increasing C/S ratio. The polymerization degree of C-S-H is increased by the carbonation reaction.

• Periodical: Advanced Materials Research (Volumes 261-263)
• Pages: 601-605
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.261-263.601
• Online since: May 2011
• Authors: Wei Chen, Wen Bing Xu, Yuan Li
• Keywords: Calcium Silicate Hydrate, Carbonation, Microstructure

References

[1] S. Ahmad, Reinforcement corrosion in concrete structures, its monitoring and service life prediction--a review. Cement and Concrete Composites, 2003. Vol. 25(4-5): pp.459-471.

DOI: 10.1016/s0958-9465(02)00086-0

[2] M. Castellote, C. Andrade, X. Turrillas, et al., Accelerated carbonation of cement pastes in situ monitored by neutron diffraction. Cement and Concrete Research, 2008. Vol. 38(12): pp.1365-1373.

DOI: 10.1016/j.cemconres.2008.07.002

[3] E. Sakai, K. Kosuge, S. Teramura, et al., Carbonation of expansive concrete and change of hydration products, in Durability of Concrete, 1991: MONTREAL , Canada. pp.989-999.

DOI: 10.14359/2457

[4] T. Nishikawa, K. Suzuki, S. Ito, S., et al., Decomposition of synthesized ettringite by carbonation. Cement and Concrete Research, 1992. Vol. 22(1): pp.6-14.

DOI: 10.1016/0008-8846(92)90130-n

[5] P.H.R. Borges, J.O. Costa, N.B. Milestone et al., Carbonation of CH and C-S-H in composite cement pastes containing high amounts of BFS. Cement and Concrete Research, 2010. Vol. 40(2): pp.284-292.

DOI: 10.1016/j.cemconres.2009.10.020

[6] H.M. Jennings, Refinements to colloid model of C-S-H in cement: CM-II. Cement and Concrete Research, 2008. Vol. 38(3): pp.275-289.

DOI: 10.1016/j.cemconres.2007.10.006

[7] C.J. Goodbrake, J.F. Young, R.L. Berger, Reaction of Hydraulic Calcium Silicates with Carbon Dioxide and Water. Journal of American Ceramic Society, 1979. Vol. 62(9): pp.488-491.

DOI: 10.1111/j.1151-2916.1979.tb19112.x

[8] F. Matsushita, Y. Aono, S. Shibata, Calcium silicate structure and carbonation shrinkage of a tobermorite-based material. Cement and Concrete Research, 2004. Vol. 34(7): pp.1251-1257.

DOI: 10.1016/j.cemconres.2003.12.016

[9] W. Xu, Z. Shui, Z., W. Chen, Carbonation of fly ash concrete investigated with microhardness analysis, in First International Conference on Sustainable Urbanization. 2010: Hong Kong.