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Title: Forced and natural carbonation of lime-based mortars with and without additives: Mineralogical and textural changes

Abstract

We have studied the carbonation process in different types of mortars, with and without pozzolana or air-entraining additives, subject to a CO{sub 2}-rich atmosphere and compared the results with those of similar naturally carbonated mortars. We used X-ray diffraction technique to demonstrate that high CO{sub 2} concentrations favour a faster, more complete carbonation process with 8 days being sufficient to convert portlandite into 90 wt.% calcite. Full carbonation, however, is not reached during the life-span of the tests, not even in forced carbonation experiments. This could be due to at least one of the following phenomena: a premature drying of samples during carbonation reaction, the temperature at which the carbonation process was carried out or the reduction of pore volume occupied by newly formed calcite crystals. This last option seems to be the least probable. We observed a more prolific development of calcite crystals in the pores and fissures through which the carbonic anhydride flows. Under natural conditions, carbonation is much slower and similar levels are not reached for 6 months. These differences suggest that the carbonation process is influenced by the amount of CO{sub 2} used. Both the mineralogy and texture of mortars vary depending on the type ofmore » additive used but the speed of the portlandite-calcite transformation does not change significantly. Pozzolana produces hydraulic mortars although the quantity of calcium aluminosilicate crystals is low. The air-entraining agent significantly alters the texture of the mortars creating rounded pores and eliminating or reducing the drying cracks.« less

Authors:
 [1];  [2];  [2]
  1. Department of Mineralogy and Petrology, University of Granada, Avda. Fuentenueva s/n, 18002 Granada (Spain). E-mail: cultrone@ugr.es
  2. Department of Mineralogy and Petrology, University of Granada, Avda. Fuentenueva s/n, 18002 Granada (Spain)
Publication Date:
OSTI Identifier:
20793259
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cement and Concrete Research; Journal Volume: 35; Journal Issue: 12; Other Information: DOI: 10.1016/j.cemconres.2004.12.012; PII: S0008-8846(05)00051-7; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ADDITIVES; ALUMINATES; CALCITE; CALCIUM COMPOUNDS; CARBON DIOXIDE; DRYING; MORTARS; X-RAY DIFFRACTION

Citation Formats

Cultrone, G., Sebastian, E., and Huertas, M. Ortega. Forced and natural carbonation of lime-based mortars with and without additives: Mineralogical and textural changes. United States: N. p., 2005. Web. doi:10.1016/J.CEMCONRES.2004.1.
Cultrone, G., Sebastian, E., & Huertas, M. Ortega. Forced and natural carbonation of lime-based mortars with and without additives: Mineralogical and textural changes. United States. doi:10.1016/J.CEMCONRES.2004.1.
Cultrone, G., Sebastian, E., and Huertas, M. Ortega. Thu . "Forced and natural carbonation of lime-based mortars with and without additives: Mineralogical and textural changes". United States. doi:10.1016/J.CEMCONRES.2004.1.
@article{osti_20793259,
title = {Forced and natural carbonation of lime-based mortars with and without additives: Mineralogical and textural changes},
author = {Cultrone, G. and Sebastian, E. and Huertas, M. Ortega},
abstractNote = {We have studied the carbonation process in different types of mortars, with and without pozzolana or air-entraining additives, subject to a CO{sub 2}-rich atmosphere and compared the results with those of similar naturally carbonated mortars. We used X-ray diffraction technique to demonstrate that high CO{sub 2} concentrations favour a faster, more complete carbonation process with 8 days being sufficient to convert portlandite into 90 wt.% calcite. Full carbonation, however, is not reached during the life-span of the tests, not even in forced carbonation experiments. This could be due to at least one of the following phenomena: a premature drying of samples during carbonation reaction, the temperature at which the carbonation process was carried out or the reduction of pore volume occupied by newly formed calcite crystals. This last option seems to be the least probable. We observed a more prolific development of calcite crystals in the pores and fissures through which the carbonic anhydride flows. Under natural conditions, carbonation is much slower and similar levels are not reached for 6 months. These differences suggest that the carbonation process is influenced by the amount of CO{sub 2} used. Both the mineralogy and texture of mortars vary depending on the type of additive used but the speed of the portlandite-calcite transformation does not change significantly. Pozzolana produces hydraulic mortars although the quantity of calcium aluminosilicate crystals is low. The air-entraining agent significantly alters the texture of the mortars creating rounded pores and eliminating or reducing the drying cracks.},
doi = {10.1016/J.CEMCONRES.2004.1},
journal = {Cement and Concrete Research},
number = 12,
volume = 35,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}