ABSTRACT Abstract The goal of this study was to explain the influence of the total porosity and t... more ABSTRACT Abstract The goal of this study was to explain the influence of the total porosity and the surface roughness on the susceptibility of clay bricks to biodegradation by phototrophic microorganisms. In addition, this correlation was studied on both specimens treated with TiO2 nanocoating and untreated control specimens. The effect of UV intensity on the photocatalytic power of TiO2 was also investigated. An accelerated fouling test was performed by sprinkling a suspension of Chlorella mirabilis and Chroococcidiopsis fissurarum on sample surfaces. These two test strains were chosen because their representativeness on building clay brick façades subjected to biofouling. The gradual superficial accumulation of algal biomass on treated and control specimens was evaluated by means of image analysis and colour measurement. Two specimens' parameters, namely porosity and roughness, were examined. Results showed that both the specimen microstructure and roughness of the surface play a key role in the colonization of clay bricks because they were able to provide more nutrient to the algal cells anchored to the surface. The TiO2 nanocoating was able to inhibit the biofouling of clay bricks irradiated with UV-A light, except in the case of high porous rough specimens.
ABSTRACT The aim of this investigation is to determine the stress intensity factor and to draw th... more ABSTRACT The aim of this investigation is to determine the stress intensity factor and to draw the R-curve of clay brick blocks by using Digital Image Correlation (DIC) method. After-the-notch pre-cracks are introduced in 30x260x60 mm notched samples by using sandwiched beam technique. The DIC method is used to measure the full displacement fields on the sample’s surface, and the crack tip position is then reconstructed by post-processing the experimental data. Due to the high precision of the DIC, we have collected many points during crack propagation, thus we have obtained a quite accurate R-curve. An average critical stress intensity factor of clay brick blocks equal to about 0.36 MPa∗m1/2 was estimated.
ABSTRACT Abstract The goal of this study was to explain the influence of the total porosity and t... more ABSTRACT Abstract The goal of this study was to explain the influence of the total porosity and the surface roughness on the susceptibility of clay bricks to biodegradation by phototrophic microorganisms. In addition, this correlation was studied on both specimens treated with TiO2 nanocoating and untreated control specimens. The effect of UV intensity on the photocatalytic power of TiO2 was also investigated. An accelerated fouling test was performed by sprinkling a suspension of Chlorella mirabilis and Chroococcidiopsis fissurarum on sample surfaces. These two test strains were chosen because their representativeness on building clay brick façades subjected to biofouling. The gradual superficial accumulation of algal biomass on treated and control specimens was evaluated by means of image analysis and colour measurement. Two specimens' parameters, namely porosity and roughness, were examined. Results showed that both the specimen microstructure and roughness of the surface play a key role in the colonization of clay bricks because they were able to provide more nutrient to the algal cells anchored to the surface. The TiO2 nanocoating was able to inhibit the biofouling of clay bricks irradiated with UV-A light, except in the case of high porous rough specimens.
ABSTRACT The aim of this investigation is to determine the stress intensity factor and to draw th... more ABSTRACT The aim of this investigation is to determine the stress intensity factor and to draw the R-curve of clay brick blocks by using Digital Image Correlation (DIC) method. After-the-notch pre-cracks are introduced in 30x260x60 mm notched samples by using sandwiched beam technique. The DIC method is used to measure the full displacement fields on the sample’s surface, and the crack tip position is then reconstructed by post-processing the experimental data. Due to the high precision of the DIC, we have collected many points during crack propagation, thus we have obtained a quite accurate R-curve. An average critical stress intensity factor of clay brick blocks equal to about 0.36 MPa∗m1/2 was estimated.
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Papers by Lorenzo Graziani