Lithological influence of aggregate in the alkali-carbonate reaction

Journal Article · Tue Aug 15 04:00:00 EDT 2006 · Cement and Concrete Research

DOI:https://doi.org/10.1016/j.cemconres.2006.05.032· OSTI ID:20871567

Lopez-Buendia, A M ^[1]; Climent, V ^[2]; Verdu, P ^[1]

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1. AIDICO-Unida Tecnica del Marmol, Cami de Castella, 4. 03660-Novelda, Alicante (Spain)
2. AIDICO, Benjamin Franklin, 17. 46980-Paterna, Valencia (Spain)

The reactivity of carbonate rock with the alkali content of cement, commonly called alkali-carbonate reaction (ACR), has been investigated. Alkali-silica reaction (ASR) can also contribute in the alkali-aggregate reaction (AAR) in carbonate rock, mainly due to micro- and crypto-crystalline quartz or clay content in carbonate aggregate. Both ACR and ASR can occur in the same system, as has been also evidenced on this paper. Carbonate aggregate samples were selected using lithological reactivity criteria, taking into account the presence of dedolomitization, partial dolomitization, micro- and crypto-crystalline quartz. Selected rocks include calcitic dolostone with chert (CDX), calcitic dolostone with dedolomitization (CDD), limestone with chert (LX), marly calcitic dolostone with partial dolomitization (CD), high-porosity ferric dolostone with clays (FD). To evaluate the reactivity, aggregates were studied using expansion tests following RILEM AAR-2, AAR-5, a modification using LiOH AAR-5Li was also tested. A complementary study was done using petrographic monitoring with polarised light microscopy on aggregates immersed in NaOH and LiOH solutions after different ages. SEM-EDAX has been used to identify the presence of brucite as a product of dedolomitization. An ACR reaction showed shrinkage of the mortar bars in alkaline solutions explained by induced dedolomitization, while an ASR process typically displayed expansion. Neither shrinkage nor expansion was observed when mortar bars were immersed in solutions of lithium hydroxide. Carbonate aggregate classification with AAR pathology risk has been elaborated based on mechanical behaviours by expansion and shrinkage. It is proposed to be used as a petrographic method for AAR diagnosis to complement the RILEM AAR1 specifically for carbonate aggregate. Aggregate materials can be classified as I (non-reactive), II (potentially reactive), and III (probably reactive), considering induced dedolomitization ACR (dedolomitization degree) and ASR.

• OSTI ID: 20871567
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 8 Vol. 36; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBONATES
CEMENTS
CLAYS
CONCRETES
EXPANSION
LIMESTONE
LITHIUM HYDROXIDES
MORTARS
POROSITY
QUARTZ
REACTIVITY
SCANNING ELECTRON MICROSCOPY
SHRINKAGE
SILICA
SODIUM HYDROXIDES