Search

The presence of TiO2 nanoparticles in a cementitious matrix induces self-cleaning capacity in the presence of UV radiation by combining two mechanisms: surface hydrophilicity and degradation of the stain agent molecules. Experimental results indicate an increase in surface water absorption and, indirectly, in the degree of hydrophilicity, with the increase in the concentration of TiO2 nanoparticles in the matrix. Degradation of organic molecules, rhodamine B, is dependent on the duration of action and intensity of UV rays and the concentration of nanoparticles in the cementitious matrix. An addition of 3-6% TiO2 is effective and sufficient for a good self-cleaning capacity of cementitious surfaces. [ABSTRACT FROM AUTHOR]

This paper presents some general directory lines regarding the development (design and effective production) of the cementitious composites with self-cleaning properties. Selfcleaning concrete represents a material containing nanomaterials, namely TiO2 nanoparticles with photocatalytic properties. Consequently, buildings facades made of a composite containing TiO2-SiO2, exhibit superhydrophilic effect on the surfaces, i.e., in the presence of UV radiation, the water reaching these surfaces have the ability to form films which take over the impurities more easily. Moreover, the research shows that these constructions retain and regenerate their aesthetic appearance even after removing UV radiation. This type of composites has the ability to decompose organic and inorganic substances: inorganic pollutants like nitrogenous or acids, sulphates present in the air or water, deposited on solid surfaces, are neutralized by decomposition into stable compounds like oxides and salts. Consequently, the use of these materials for building construction leads to effective cost reduction concerning the building maintenance, washing and repair, decontamination and sterilization and even potential unpleasant urban odours prevention. [ABSTRACT FROM AUTHOR]

The field of construction is considered as a priority in terms of influence on the environment. Attention of researchers is now focused on composite materials made from natural or recycled fillers with clay, cementious or polymerics matrices, among which the non-toxic and biodegradable - Eco-composites, are highlighted. These are attractive because they are safer and more environmentally friendly. Eco-composites are a special category of composite materials, using materials that have the least impact on the environment and, eventually, waste and recycled materials. Usually, a low-impact material matrix is selected and the materials from recycling or recovery of some by-products from other industries. This paper is a brief presentation of the composite materials used in the construction field, classified according to the matrix type and to the filler material type (with emphasis on the reinforcing fibers types). The paper presents a series of research results in the field, reported in the literature and an analysis of the advantages and disadvantages, for each case. Starting from what is already known and presented at the moment, it is possible to say that the research is directed towards the identification of new technologies for the production of composite materials with low impact on the environment, durable and according to the concept of "circular economy". [ABSTRACT FROM AUTHOR]