Skip to Content
MilliporeSigma
  • On the role of hydrophobic Si-based protective coatings in limiting mortar deterioration.

On the role of hydrophobic Si-based protective coatings in limiting mortar deterioration.

Environmental science and pollution research international (2015-07-15)
G Cappelletti, P Fermo, F Pino, E Pargoletti, E Pecchioni, F Fratini, S A Ruffolo, M F La Russa
ABSTRACT

In order to avoid both natural and artificial stone decay, mainly due to the interaction with atmospheric pollutants (both gases such as NOx and SO2 and particulate matter), polymeric materials have been widely studied as protective coatings enable to limit the penetration of fluids into the bulk material. In the current work, an air hardening calcic lime mortar (ALM) and a natural hydraulic lime mortar (HLM) were used as substrates, and commercially available Si-based resins (Alpha®SI30 and Silres®BS16) were adopted as protective agents to give hydrophobicity features to the artificial stones. Surface properties of coatings and their performance as hydrophobic agents were studied using different techniques such as contact angle measurements, capillary absorption test, mercury intrusion porosimetry, surface free energy, colorimetric measurements and water vapour permeability tests. Finally, some exposure tests to UV radiation and to real polluted atmospheric environments (a city centre and an urban background site) were carried out during a wintertime period (when the concentrations of the main atmospheric pollutants are higher) in order to study the durability of the coating systems applied. The effectiveness of the two commercial resins in reducing salt formation (sulphate and nitrate), induced by the interaction of the mortars with the atmospheric pollutants, was demonstrated in the case of the HLM mortar. Graphical Abstract ᅟ.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Silica, fumed, powder, 0.2-0.3 μm avg. part. size (aggregate)
Sigma-Aldrich
Silica, fumed, powder
Sigma-Aldrich
Silica, mesostructured, MSU-F (cellular foam)
Sigma-Aldrich
Silicon dioxide, acid washed
Sigma-Aldrich
Silicon dioxide, granular, ≥99.9%
Sigma-Aldrich
Silicon dioxide, fused (granular), 4-20 mesh, 99.9% trace metals basis
Sigma-Aldrich
LUDOX® SM colloidal silica, 30 wt. % suspension in H2O
Sigma-Aldrich
Silicon dioxide, −325 mesh, 99.5% trace metals basis
Sigma-Aldrich
LUDOX® HS-30 colloidal silica, 30 wt. % suspension in H2O
Sigma-Aldrich
LUDOX® LS colloidal silica, 30 wt. % suspension in H2O
Sigma-Aldrich
LUDOX® TM-40 colloidal silica, 40 wt. % suspension in H2O
Supelco
Silica, 99.8%
Sigma-Aldrich
Silicon dioxide, acid washed and calcined, Analytical Reagent
Sigma-Aldrich
Silicon dioxide, washed and calcined, analytical reagent
Sigma-Aldrich
Silica, nanopowder, 99.8% trace metals basis
Sigma-Aldrich
Silicon dioxide, JIS special grade
Sigma-Aldrich
Silicon dioxide, nanopowder (spherical, porous), 5-20 nm particle size (TEM), 99.5% trace metals basis
Sigma-Aldrich
Silicon dioxide, nanopowder, 10-20 nm particle size (BET), 99.5% trace metals basis
Sigma-Aldrich
Silica, mesostructured, MCM-41 type (hexagonal)
Sigma-Aldrich
Silicon dioxide, single crystal substrate, optical grade, 99.99% trace metals basis, L × W × thickness 10 mm × 10 mm × 0.5 mm
Supelco
Glass spheres
Sigma-Aldrich
Silica
Sigma-Aldrich
LUDOX® CL colloidal silica, 30 wt. % suspension in H2O
Sigma-Aldrich
Silicon dioxide, purum p.a., acid purified
Sigma-Aldrich
Silicon dioxide, purum p.a., acid purified, sand
Sigma-Aldrich
Silica, mesostructured, SBA-15, 99% trace metals basis
Sigma-Aldrich
Silica, nanoparticles, mesoporous, 200 nm particle size, pore size 4 nm
Sigma-Aldrich
Silicon dioxide, ~99%, 0.5-10 μm (approx. 80% between 1-5 μm)
Sigma-Aldrich
1-Naphthyl phosphate monosodium salt monohydrate, ≥98% (titration), powder
Sigma-Aldrich
Activated charcoal, suitable for cell culture, suitable for plant cell culture