Effect of Carbonation Curing on Efflorescence Formation in Concrete Paver Blocks
Publication: Journal of Materials in Civil Engineering
Volume 32, Issue 6
Abstract
Efflorescence is a staining salt deposit that usually forms on or near the surface of portland concrete products. It is not an indication of internal damage, but rather an aesthetic blemish that affects a product’s appearance, leading to higher replacement and rejection rates. The primary goal of this work was to investigate whether early-age carbonation curing helps reduce or eliminate efflorescence formation in concrete paver blocks. The devised carbonation technique involved curing concrete pavers in a chamber filled with either pure-gas (99.5% carbon dioxide concentration) or flue-gas (20% carbon dioxide concentration) under a pressure of 5 bar. Efflorescence formation in hydrated and carbonated pavers was evaluated using a modified wicking test. A MATLAB-assisted image-analysis technique was used to quantify efflorescence severity. Results clearly show that pure-gas carbonation successfully eliminated surface efflorescence compared to paver batches that underwent flue-gas carbonation and conventional hydration curing. This improved performance was attributed mainly to a reduction in permeability, which in turn was a result of the densifying precipitation of calcium carbonate crystals during pure-gas carbonation. Results from X-ray diffraction (XRD) and scanning electron microscope (SEM)—coupled with energy-dispersive X-ray spectroscopy (EDX)—identified efflorescence as crystalline potassium-sulfate-based salt deposits.
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Data Availability Statement
Some or all data, models, or code generated or used during the study are available from the corresponding author by request:
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Compressive strength data
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XRD spectrum data
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MatLab image analysis code
Acknowledgments
The financial support by the Natural Sciences and Engineering Research Council (NSERC) of Canada is gratefully acknowledged. The authors are also thankful to Dr. Mohammed Al-Farhan, Managing Director, Ducon Industries in Dubai, UAE for his generous help.
References
Andrés, A., M. C. Díaz, A. Coz, M. J. Abellán, and J. R. Viguri. 2009. “Physico-chemical characterisation of bricks all through the manufacture process in relation to efflorescence salts.” J. Eur. Ceram. Soc. 29 (10): 1869–1877. https://doi.org/10.1016/j.jeurceramsoc.2008.11.015.
ASTM. 2013. Standard test method for density, absorption, and voids in hardened concrete. ASTM C642. West Conshohocken, PA: ASTM.
ASTM. 2014. Standard test methods for sampling and testing brick and structural clay tile. ASTM C67. West Conshohocken, PA: ASTM.
Brocken, H., and T. G. Nijland. 2004. “White efflorescence on brick masonry and concrete masonry blocks, with special emphasis on sulfate efflorescence on concrete blocks.” Constr. Build. Mater. 18 (5): 315–323. https://doi.org/10.1016/j.conbuildmat.2004.02.004.
Chandigarh, T. 2001. Civil engineering materials. New York: McGraw-Hill.
Chin, I. R., and L. Petry. 1993. Design and testing to reduce efflorescence potential in new brick masonry walls. West Conshohocken, PA: ASTM.
Dow, C., and F. P. Glasser. 2003. “Calcium carbonate efflorescence on portland cement and building materials.” Cem. Concr. Res. 33 (1): 147–154. https://doi.org/10.1016/S0008-8846(02)00937-7.
El-Hassan, H., Y. Shao, and Z. Ghouleh. 2013. “Reaction products in carbonation-cured lightweight concrete.” J. Mater. Civ. Eng. 25 (6): 799–809. https://doi.org/10.1061/(ASCE)MT.1943-5533.0000638.
Fernández Bertos, M., S. J. R. Simons, C. D. Hills, and P. J. Carey. 2004. “A review of accelerated carbonation technology in the treatment of cement-based materials and sequestration of .” J. Hazard. Mater. 112 (3): 193–205.
Kresse, P. 1987. “Efflorescence-mechanism of occurrence and possibilities of prevention.” Betonwerk+ Fertigteil-Technik 53 (3): 160–168.
Monkman, S., and Y. Shao. 2006. “Assessing the carbonation behavior of cementitious materials.” J. Mater. Civ. Eng. 18 (6): 768–776. https://doi.org/10.1061/(ASCE)0899-1561(2006)18:6(768).
Moukwa, M., and T. Vickers. 1996. “Evaluation of test methods and environmental conditions to promote efflorescence formation under laboratory conditions.” J. Test. Eval. 24 (2): 80–83.
Neville, A. M. 2002. “Efflorescence: Surface blemish or internal problem. I: The knowledge.” Concr. Int. 24 (8): 86–90.
Norsuzailina, M. S., H. Sinin, Y. Ibrahim, and A. T. Zainal. 2014. “Efflorescence mitigation by pozzolanic industrial by-products.” Malaysian J. Civ. Eng. 26 (2): 198–208.
Shao, Y., and X. Lin. 2011. “Early-age carbonation curing of concrete using recovered CO2.” Concr. Int. 33 (9): 50–56.
Shoji, M., T. Higuchi, M. Morioka, and K. Yokozeki. 2015. “Inhibitory effect of alkali-silica reaction by the carbonation reaction.” Cem. Sci. Concr. Technol. 69 (1): 504–510. https://doi.org/10.14250/cement.69.504.
Young, J. F., R. L. Berger, and J. Breese. 1974. “Accelerated curing of compacted calcium silicate mortars on exposure to .” J. Am. Ceram. Soc. 57 (9): 394–397. https://doi.org/10.1111/j.1151-2916.1974.tb11420.x.
Zhang, D., and Y. Shao. 2016. “Effect of early carbonation curing on chloride penetration and weathering carbonation in concrete.” Constr. Build. Mater. 123 (Oct): 516–526. https://doi.org/10.1016/j.conbuildmat.2016.07.041.
Zhang, D., and Y. Shao. 2018. “Surface scaling of -cured concrete exposed to freeze-thaw cycles.” J. Util. 27 (Oct): 137–144. https://doi.org/10.1016/j.jcou.2018.07.012.
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Published In
Journal of Materials in Civil Engineering
Volume 32 • Issue 6 • June 2020
Copyright
©2020 American Society of Civil Engineers.
History
Received: May 28, 2019
Accepted: Dec 2, 2019
Published online: Mar 24, 2020
Published in print: Jun 1, 2020
Discussion open until: Aug 24, 2020
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