Influence of porosity and relative humidity on consolidation of dolostone with calcium hydroxide nanoparticles: Effectiveness assessment with non-destructive techniques

• Published in: Materials characterization Vol. 61; no. 2; pp. 168 - 184
• Main Authors: López-Arce, P., Gomez-Villalba, L.S., Pinho, L., Fernández-Valle, M.E., de Buergo, M. Álvarez, Fort, R.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.02.2010; Elsevier
• Subjects: CALCITE; CALCIUM CARBONATES; Calcium hydroxide nanoparticles; CALCIUM HYDROXIDES; Consolidation; Cross-disciplinary physics: materials science; rheology; DOLOMITE; Exact sciences and technology; HUMIDITY; MATERIALS SCIENCE; NANOSCIENCE AND NANOTECHNOLOGY; NANOSTRUCTURES; Non-destructive techniques; NUCLEAR MAGNETIC RESONANCE; PARTICLES; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; POROSITY; POROUS MATERIALS; RECRYSTALLIZATION; ROUGHNESS; SCANNING ELECTRON MICROSCOPY; Solidification; SPECTROPHOTOMETRY; Stone; SURFACES; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; Consolidation; Porosity; Calcium hydroxide nanoparticles; Stone; Humidity; Non-destructive techniques; Nanoparticles
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2009.11.007

Slaked lime (Ca(OH) 2) nanoparticles were exposed at 33% and 75% relative humidity (RH) to consolidate dolostone samples used in historical buildings. Non-destructive techniques (NDT) were applied to determine the chemical, morphological, physical and hydric properties of the stone samples, before and after 20 days treatment. Morphological and mineralogical characterisation of the nanoparticles was performed. 75% RH favors the consolidation process studied under Environmental Scanning Electron Microscopy (ESEM-EDS), spectrophotometry, capillarity, water absorption under vacuum, ultrasound velocity, Nuclear Magnetic Resonance (imaging and relaxometry) and Optical Surface Roughness analyses. At 75% RH the nanoparticles fill the pores and inter-crystalline dolomite grain contacts but do not favor calcite re-crystallization as it occurs at 33% RH. The ESEM, XRD and TEM analyses under 75% RH reveal the fast transformation of portlandite (Ca(OH) 2) into vaterite (CaCO 3), monohydrocalcite (CaCO 3 · H 2O) and calcite (CaCO 3), and eventually the physical and hydric properties of the stones significantly improve. New insights are provided for the assessment of consolidation effectiveness of porous carbonate stones with calcium hydroxide nanoparticles under optimum RH conditions combining several NDT.