Maravelaki, N.

Improvement of properties of hydraulic mortars with addition of nano-titania

Abstract eng:
In this work nano-titania in anatase form has been added to mortars containing (a): binders of either lime and metakaolin or natural hydraulic lime and, (b): fine aggregates of carbonate nature. The aim was to assess the adhesive performance of the above binders for reassembling fragment porous stones and more specifically to explore the effect of nano-titania in the hydration and carbonation of the derived mortars. The nano-titania proportion was 4.5-6% w/w of binders. The physicochemical and mechanical properties of the nano-titania mortars were studied and compared to the respective ones of the mortars without the nano-titania addition, used as reference. DTA-TG, FTIR, SEM and XRD analyses indicated the evolution of carbonation, hydration and hydraulic compound formation during a period of one-year curing. The mechanical characterization indicated that the mortars with the nano-titania addition showed improved mechanical properties over time, when compared to the specimens without nano-titania. The results evidenced carbonation and hydration enhancement of the mortar mixtures with nano-titania. The hydrophylicity of nano-titania enhances humidity retention in mortars, thus facilitating the carbonation and hydration processes. This property can be exploited in the fabrication of mortars for reassembling fragments of porous limestones from monuments, where the presence of humidity controls the mortar setting and adhesion efficiency. A specifically designed mechanical experiment based on direct tensile strength proved the suitability of mortars with nano-titania as potential adhesive means for restoration applications. The rapid discoloration of methylene blue stains applied to mortars with nano-titania supported the self-cleaning properties of mortars with nano-titania presence. Based on the physicochemical and mechanical characterization of the studied adhesive mortars with nano-titania, binders of metakaolin-lime and natural hydraulic lime have been selected as most appropriate formulations for the adhesion of fragment porous stones in restoration applications.

Contributors:

Ioannou, I.

Publisher:

Glasgow : University of the West of Scotland, 2013

Conference Title:

Proceedings of the 3rd Historic Mortars Conference HMC13

Conference Title:

3rd Historic Mortars Conference

Conference Venue:

Glasgow, Scotland (UK)

Conference Dates:

2013-09-11 / 2013-09-14