Opportunities regarding the potential use of the self-cleaning concept within urban contemporary architecture in Romania

Abstract

Contemporary urban architecture faces two important issues: degradation of buildings, caused by exposure to various environmental factors (air and water pollution, mainly generated by the fuels combustion used for transport and heating) and also the costs for repair, cleaning and maintenance of the buildings facades. Regarding the last mentioned aspects, recent research led to development of materials with self-cleaning potential and consequently pollution reduction. Self-cleaning concrete represents a state-of-the-art material with photocatalytic properties generated by the addition in its composition of nanomaterials like TiO2. Already known for its intrinsic photocatalytic character, TiO2 has the ability to catalyse the decomposition of organic substances like grease and dirt, facilitating their quick removal only by rainwater action. Therefore, a building façade made of TiO2-SiO2-containing material develops substantial savings regarding maintenance costs, water consumption and less detergents contamination due to its intrinsic super hydrophilic effect of the surface in the presence of UV radiation, leading to easy dirt removal when water reaches it. The aim of present paper is presenting the latest stage of worldwide research regarding the obtaining of self-cleaning concrete and also the possibility of adapting the concept to the actual Romanian architecture needs, as a sustainable solution for urban pollution reduction.

Photoactive Cements: A Review

“…An important issue concerning the use of photocatalysts in construction materials is the influence of the added additive on the mechanical and operational properties of cementitious substrates. Studies in this area have shown that the introduction of a photocatalyst affects the properties of fresh cement mortar, and the introduction of nanoparticles has a physicochemical effect [ 115 , 116 ].…”

“…A certain trend has been noticed so far. It has been reported that the greater the amount of titanium nanoparticles, the worse the workability of cement composites [ 115 ]. This was observed both in simple mixtures of cement slags and in composites with the addition of slag [ 115 ].…”

“…It has been reported that the greater the amount of titanium nanoparticles, the worse the workability of cement composites [ 115 ]. This was observed both in simple mixtures of cement slags and in composites with the addition of slag [ 115 ]. For example, Jimenez-Relinque et al [ 6 ] found that the addition of 2 wt.% TiO 2 causes a decrease in workability in the case of mortars prepared from various types of binders: OPC, CAC, fly ash, or slag.…”

“…In turn, the 10% additive increased compressive strength after 1 and 7 days, but decreased it after 3 and 28 days. Overall, at the ratio w/b = 0.4, an increase in compressive strength was observed with the increase in the content of TiO 2 nanoparticles, and in the case of w/b = 0.5 and 0.6, an opposite trend was observed [ 33 , 115 ].…”

“…TiO 2 particles are characterized by a high degree of whiteness, but their relatively even weight distribution does not affect the possibility of dyeing with conventional pigments. After dyeing the composite mass, no time loss was observed due to the photocatalytic activity of TiO 2 nanoparticles [ 115 ].…”