Chinchón Payá, Servando, Andrade, Carmen, Chinchón Yepes, Servando
Indicator of carbonation front in concrete as substitute to phenolphthalein
Cement and Concrete Research. 2016, 82: 87-91. doi:10.1016/j.cemconres.2015.12.010
URI: http://hdl.handle.net/10045/62517
DOI: 10.1016/j.cemconres.2015.12.010
ISSN: 0008-8846 (Print)
Abstract: 
A method to substitute the recognized toxic phenolphthalein in mortars and concretes is proposed. It comprises putting a portland cement sample in contact with an innocuous solution, curcumin-based, which acts as an indicator yielding a red color in areas where there is alkaline reserve (pH ~ 12) and yellow in carbonate zones (pH ≤ 9). Solutions containing curcumin extracted from commercial turmeric powder and from the rhizomes of the turmeric plant were prepared by using ethanol as a solvent. Subsequently it has been experienced with solutions in which curcumin has been used with a purity of over 95%. The dissolution of curcumin can be used with the same reliability as phenolphthalein in the carbonation process with the advantage that it is safe and presents no health risks.
Keywords:Carbonation, Concrete, Mortar
Elsevier
info:eu-repo/semantics/article