Consolidating effects of nano-lime products on porous lime renders and limestone

0462131 - ÚTAM 2017 RIV FR eng A - Abstract
Slížková, Zuzana
Consolidating effects of nano-lime products on porous lime renders and limestone.
International RILEM Conference on Materials, Systems and Structures in Civil Engineering. Segment on Historical Masonry. Paris: RILEM Publications, 2016 - (Rörig-Dalgaard, I.; Ioannou, I.). s. 259-259. ISBN 978-2-35158-174-2.
[International RILEM Conference on Materials, Systems and Structures in Civil Engineering. Conference segment on Historical Masonry. 22.08.2016-24.08.2016, Lyngby]
R&D Projects: GA MŠMT(CZ) LO1219
Keywords : lime renders * limestone * CaLoSiL IP * CaLoSiL E * consolidation
Subject RIV: AL - Art, Architecture, Cultural Heritage

The study presented in this article was focused on the consolidating effects of CaLoSiL E (nanoparticles dispersed in ethanol) and CaLoSiL JP (in isopropyl alcohol) applied on lime based substrates, namely porous lime mortars and porous limestone. As nanolime particles in the consolidating product CaLoSiL have a size with diameter in range 50-200 nm, the degraded building material to be treated should ideally contain much larger pores or cracks to absorb the liquid consolidant effectively into its pores structure. For the experiment presented here, porous Maastricht stone with pores size 48 μm and weak lime mortars with significant part of pores with a diameter 10-100 μm were used. Besides the mechanical properties of the treated specimens of mortar and stone (compressive and flexural strength), the influence on porosity and the colour of building materials was also monitored. The amount of the product applied was observed and subsequent treatment cycles with the same product were carried out a few days later, on fully dried material. Various concentrations of nano lime in the products were tested (15 - 50 g/1). The greatest strengthening effect was observed for the poorest mortar (1:9), which showed eight times higher compressive strength after 10 applications of nanolime. The measured flexural strength was three times higher than the initial one after 10 treatments and the water accessible porosity slightly dropped, from 32% to 28.8%. It was concluded that 5-7 repeated treatments of CaLoSiL E 25 can be recommended for the consolidation of very weak lime mortar with bad cohesion and 3-5 treatments for the consolidation of mortar with better cohesion. In the case of the Maastricht stone, 2 repeated treatments with CaLoSiL E 25 performed the best. It should be noticed that high concentrated product (50g/1) and higher amount of applied nanolime led to a change of surface colour to whitish tones, which may be considered in some cases unacceptable.
Permanent Link: http://hdl.handle.net/11104/0261657