TY - JOUR
T1 - Consolidation of a Tunisian bioclastic calcarenite
T2 - From conventional ethyl silicate products to nanostructured and nanoparticle based consolidants
AU - Zornoza-Indart, Ainara
AU - Lopez-Arce, Paula
AU - Leal, Nuno
AU - Simão, Joaquim
AU - Zoghlami, Karima
N1 - This work has been carried out at Instituto de Geociencias (CSIC,UCM) and supported by Rafael Fort and GEOMATERIALES (S2009/MAT-1629) Program. The work was also supported by a JAE-PreDoc fellowship program (2010–2014) of the Spanish National Research Council (CSIC) and the Adaptability and Employment Program of the European Social Fund (ESF 2007–2013). The work was carried out from a collaboration between Universidad Complutense de Madrid (UCM) and Faculty of Sciences of Bizerte (Tunisia) under the AECID AP/042080/11 project. Special thanks to Maria Jesús Mosquera and Luis Pinho of the Departamento de Química-Física, Universidad de Cádiz (Spain) for providing the surfactant-templated novel sol-gel product. Thanks also to Ana Vicente for the SEM analyses performed at the ICTS, Centro Nacional de Microscopia Electronica (UCM), and Maria Jose Varas (UCM) for founding the analyses.
PY - 2016/7/30
Y1 - 2016/7/30
N2 - Mediterranean calcarenite stones are exposed to several weathering processes related to the climate and environment, producing alteration features conducing to loss of cohesion in their structures. Samples of these building materials were collected from the Spanish Fort of Bizerte (Tunisia) to carry out laboratory tests in order to assess the consolidation effect of the nowadays most frequently used products and most innovative consolidation materials based in nanoparticles. Stone specimens were consolidated with the most employed alkoxysilane product (ethyl silicate), with a surfactant-templated novel sol-gel product (that avoids the tendency to crack) and with inorganic products based on calcium hydroxide nanoparticles (Ca(OH)2) and silica nanoparticles (SiO2) under very humid and dry environmental conditions. Samples were characterized by scanning electron microscopy, peeling test, superficial hardness, drilling resistance, water absorption by capillarity and under vacuum, water desorption and spectrophotometry, before and after one month of the application of the products to evaluate their consolidation effect under different environmental conditions. The results show great differences in the consolidation effect and in the changes produced in the physical properties of the substrate after using alkoxysilane products (even nanostructured) or products based in nanoparticles. In the case of alkoxysilane and nanostructured products, especially exposed to high RH conditions, the mechanical properties of the substrate, internal and surface, increase. In both cases a layer on the substrate which occludes the pores is generated maintaining a hydrophobic behavior after one month causing drastic changes in the hydric behavior with visually detectable aesthetic changes. In the case of inorganic nanoparticles, changes in the porosity of the substrate caused by the creation of micropores occur in both cases. In the case of SiO2 nanoparticles, moderate physical changes occur in dry conditions resulting in less shrinkage and color changes. Finally, Ca(OH)2 nanoparticles are the products with the lowest surface and internal consolidation effectiveness which barely change the physical properties of the stone.
AB - Mediterranean calcarenite stones are exposed to several weathering processes related to the climate and environment, producing alteration features conducing to loss of cohesion in their structures. Samples of these building materials were collected from the Spanish Fort of Bizerte (Tunisia) to carry out laboratory tests in order to assess the consolidation effect of the nowadays most frequently used products and most innovative consolidation materials based in nanoparticles. Stone specimens were consolidated with the most employed alkoxysilane product (ethyl silicate), with a surfactant-templated novel sol-gel product (that avoids the tendency to crack) and with inorganic products based on calcium hydroxide nanoparticles (Ca(OH)2) and silica nanoparticles (SiO2) under very humid and dry environmental conditions. Samples were characterized by scanning electron microscopy, peeling test, superficial hardness, drilling resistance, water absorption by capillarity and under vacuum, water desorption and spectrophotometry, before and after one month of the application of the products to evaluate their consolidation effect under different environmental conditions. The results show great differences in the consolidation effect and in the changes produced in the physical properties of the substrate after using alkoxysilane products (even nanostructured) or products based in nanoparticles. In the case of alkoxysilane and nanostructured products, especially exposed to high RH conditions, the mechanical properties of the substrate, internal and surface, increase. In both cases a layer on the substrate which occludes the pores is generated maintaining a hydrophobic behavior after one month causing drastic changes in the hydric behavior with visually detectable aesthetic changes. In the case of inorganic nanoparticles, changes in the porosity of the substrate caused by the creation of micropores occur in both cases. In the case of SiO2 nanoparticles, moderate physical changes occur in dry conditions resulting in less shrinkage and color changes. Finally, Ca(OH)2 nanoparticles are the products with the lowest surface and internal consolidation effectiveness which barely change the physical properties of the stone.
KW - Calcium hydroxide nanoparticles
KW - Consolidation
KW - Ethyl silicate
KW - Relative humidity
KW - Silica nanoparticles
KW - Stone
UR - http://www.scopus.com/inward/record.url?scp=84966783537&partnerID=8YFLogxK
U2 - 10.1016/j.conbuildmat.2016.04.114
DO - 10.1016/j.conbuildmat.2016.04.114
M3 - Article
AN - SCOPUS:84966783537
SN - 0950-0618
VL - 116
SP - 188
EP - 202
JO - Construction and Building Materials
JF - Construction and Building Materials
ER -