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

Author(s): Zuzuna Silijkova
Paper category: Proceedings
Book title: Proceedings of the International RILEM Conference
Materials, Systems and Structures in Civil Engineering 2016 segment on
Historical Masonry
Editor(s): Inge Rörig-Dalgaard and Ioannis Ioannou
ISBN: 978-2-35158-178-0
e-ISBN: 978-2-35158-179-7
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 272-272
Total Pages: 1
Language : English

Abstract: In many sectors of the industry it is currently possible to observe a growing interest in the
development and application of nanotechnologies and nanomaterials. The latter have been
applied, among others, also in the field of conservation of architectural heritage. One example
of this application is the consolidating treatment of disintegrated lime mortars and limestone
with nanoparticles of calcium hydroxide dispersed in alcohol.
The study presented in this article was focused on the consolidating effects of CaLoSiL E
(nanoparticles dispersed in ethanol) and CaLoSiL IP (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 consolidation treatment
with nanolime was carried out by slowly impregnating the surface of mortar or stone
specimens with liquid consolidant up to full infiltration, by means of a syringe. 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 nanolime
in the products were tested (15 - 50 g/l).
All tested nano-lime products penetrated well into all mortar and stone samples. 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/l) and higher amount of applied
nanolime led to a change of surface colour to whitish tones, which may be considered in some
cases unacceptable.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00