Alkali-dolomite reaction in air lime mortar : implications for increased strength and water resistance

Štukovnik, Petra (author), Bokan-Bosiljkov, Violeta (author), Marinšek, Marjan (author)

This paper investigates the origin of increased strength and water resistance of air lime mortar prepared by Triassic dolomite aggregate when exposed to humid or wet environments. The mortar specimens were exposed to various ageing conditions and analysed using petrographic and scanning electron microscopy equipped with X-ray microanalysis. Parallel to these analyses, X-ray powder diffraction and strength tests were performed on the specimens. It was revealed that reactions associated with the dedolomitisation process of the dolomite grains in the lime binder (hereafter alkali-carbonate reactions or ACRs) are the source of the improved strength and water resistance. An increasingly alkaline environment accelerated the ACRs substantially. Two parallel processes during the ACRs (dedolomitisation and CaCO$_3$ dissolution/reprecipitation) were described in detail. Ageing temperature decisively influenced the kinetics of the dedolomitisation and dictated the path of the CaCO$_3$ dissolution/reprecipitation process. After two years of ageing in a water-saturated environment at 60°C, air lime mortar retained a great deal of its initial mechanical strength, and at 20°C its strength was considerably increased. This somewhat unexpected observation was explained as being a result of microstructural changes and/or phase transitions.

• Language: English
• Keywords: lime mortar, alkali-carbonate reactions, mechanical properties, CaCO$_3$ dissolution/reprecipitation, civil engineering materials
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FGG - Faculty of Civil and Geodetic Engineering; FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2020
• Number of pages: Str. 160-168
• Numbering: Vol. 45
• PID: 20.500.12556/RUL-114958
• UDC: 691
• ISSN on article: 1296-2074
• DOI: 10.1016/j.culher.2020.02.007
• COBISS.SI-ID: 9109089
• Publication date in RUL: 02.04.2020

Record is a part of a journal

• Title: Journal of cultural heritage
• Shortened title: J. cult. herit.
• Publisher: Elsevier, Consiglio Nazionale delle Ricerche
• ISSN: 1296-2074
• COBISS.SI-ID: 1228053

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
• Licensing start date: 17.02.2020

Secondary language

• Language: Slovenian
• Keywords: gradbeni materiali, apnena malta, alkalno-karbonatne reakcije, mehanske lastnosti, CaCO$_3$ raztapljanje/obarjanje