Effect of process parameters on the photocatalytic soot degradation on self-cleaning cementitious materials

2014 ◽  
Vol 230 ◽  
pp. 250-255 ◽  
Author(s):  
Marianne Smits ◽  
Dieter Huygh ◽  
Bart Craeye ◽  
Silvia Lenaerts
Keyword(s):  
Process Parameters ◽  
Cementitious Materials ◽  
Self Cleaning

Photocatalysis of Cementitious Materials: Clean Buildings and Clean Air

MRS Bulletin ◽  
2004 ◽  
Vol 29 (5) ◽  
pp. 328-331 ◽  
Author(s):  
Luigi Cassar
Keyword(s):  
Uv Light ◽  
Environmental Pollutants ◽  
Cementitious Materials ◽  
Heterogeneous Photocatalysis ◽  
Aesthetic Quality ◽  
Global Environmental ◽  
Clean Air ◽  
Self Cleaning ◽  
High Level ◽  
Building Walls

AbstractWhile the primary function of concrete is structural, its pervasiveness in our society lends it to other functions and creates the need for it to maintain its integrity and aesthetic quality. Therefore, concrete with added functionality–for example, self-cleaning characteristics and the ability to remove pollutants–is desirable. Heterogeneous photocatalysis (e.g., gas–solid or liquid–solid catalytic processes caused by light irradiation) by semiconductor particles or coatings has now reached a high level of development and is a promising technology for the reduction of global environmental pollutants. Among the various semiconductor materials, TiO2 in the form of anatase has attracted wide interest, due to its strong oxidizing power under near-UV radiation, its chemical stability when exposed to acidic and basic compounds, its chemical inertness in the absence of UV light, and the absence of toxicity. TiO2 has proved very effective in the reduction of pollutants such as NOx, aromatics, ammonia, and aldehydes. Surprisingly, the use of TiO2 in combination with cementitious materials has shown a favorable synergistic effect in the reduction of pollutants. These new materials have already found relevant applications in self-cleaning building walls and in the reduction of urban pollutants.

scholarly journals Influence of TiO2 Nanoparticles Addition on the Hydrophilicity of Cementitious Composites Surfaces

2020 ◽  
Vol 10 (13) ◽  
pp. 4501 ◽  
Author(s):  
Andreea Hegyi ◽  
Henriette Szilagyi ◽  
Elvira Grebenișan ◽  
Andrei Victor Sandu ◽  
Adrian-Victor Lăzărescu ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Experimental Tests ◽  
Cementitious Materials ◽  
Cementitious Composites ◽  
Area Of Interest ◽  
Surface Performance ◽  
Self Cleaning ◽  
Case Basis ◽  
Intended Use

The effect of the use of TiO2 nanoparticles in the production of cementitious composites, worldwide already known, represents an area of interest for the development of materials with self-cleaning capacity; antimicrobial, antibacterial, antifungal properties; and to contribute to the reduction of environmental pollution. This paper aims to analyze the influence that TiO2 nanoparticles have on the cementitious matrix regarding hydrophilicity, this being one of the two main parameters of the self-cleaning mechanism. Experimental tests, conducted by using the indirect method of measuring the surface water absorption, indicated that an addition of 3%-6% (relative to the amount of cement) of TiO2 nanoparticles is effective in terms of increasing the surface hydrophilicity of the cementitious composites. An excess of TiO2 nanoparticles in the composite matrix (10% TiO2 nanoparticles relative to the amount of cement) not only does not improve surface performance in terms of hydrophilicity, but also reduces them. However, in practice on a case-by-case basis, an analysis is required regarding the optimal amount of nanoparticles used as an addition in the mix-design of the cementitious materials that are intended to induce the quality of self-cleaning process, depending on the intended use, climate, degree and duration of sunlight, and so on.

Photocatalytic degradation of soot deposition: Self-cleaning effect on titanium dioxide coated cementitious materials

2013 ◽  
Vol 222 ◽  
pp. 411-418 ◽  
Author(s):  
Marianne Smits ◽  
Chun kit Chan ◽  
Tom Tytgat ◽  
Bart Craeye ◽  
Nathalie Costarramone ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Cementitious Materials ◽  
Soot Deposition ◽  
Self Cleaning

scholarly journals Microstructural Characterization of 3D Printed Cementitious Materials

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2993 ◽  
Author(s):  
Jolien Van Der Putten ◽  
Maxim Deprez ◽  
Veerle Cnudde ◽  
Geert De Schutter ◽  
Kim Van Tittelboom
Keyword(s):  
Process Parameters ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Microstructural Characterization ◽  
Lower Surface ◽  
Cementitious Materials ◽  
Lower Amount ◽  
Time Interval ◽  
3D Printed ◽  
Printing Speed

Three-dimensional concrete printing (3DCP) has progressed rapidly in recent years. With the aim to realize both buildings and civil works without using any molding, not only has the need for reliable mechanical properties of printed concrete grown, but also the need for more durable and environmentally friendly materials. As a consequence of super positioning cementitious layers, voids are created which can negatively affect durability. This paper presents the results of an experimental study on the relationship between 3DCP process parameters and the formed microstructure. The effect of two different process parameters (printing speed and inter-layer time) on the microstructure was established for fresh and hardened states, and the results were correlated with mechanical performance. In the case of a higher printing speed, a lower surface roughness was created due to the higher kinetic energy of the sand particles and the higher force applied. Microstructural investigations revealed that the amount of unhydrated cement particles was higher in the case of a lower inter-layer interval (i.e., 10 min). This phenomenon could be related to the higher water demand of the printed layer in order to rebuild the early Calcium-Silicate-Hydrate (CSH) bridges and the lower amount of water available for further hydration. The number of pores and the pore distribution were also more pronounced in the case of lower time intervals. Increasing the inter-layer time interval or the printing speed both lowered the mechanical performance of the printed specimens. This study emphasizes that individual process parameters will affect not only the structural behavior of the material, but they will also affect the durability and consequently the resistance against aggressive chemical substances.

scholarly journals Optimization of the Process Parameters Controlling the Degree of Amorphization during Mechanical Activation of Clay Using the Taguchi Method

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 15
Author(s):  
Tole ◽  
Habermehl-Cwirzen ◽  
Cwirzen
Keyword(s):  
Taguchi Method ◽  
Mechanical Activation ◽  
Process Parameters ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Main Peak ◽  
Activation Process ◽  
Statistical Tool ◽  
Before And After ◽  
Environmentally Friendly Process

Mechanical activation in a planetary ball mill (BM) is an environmentally friendly process able to enhance the chemical and pozzolanic activity of natural clays. Those materials can be used as supplementary cementitious materials (SCMs) to partially replace Portland cement in concrete. The process parameters of the BM are directly related to the degree of amorphization and thus to the enhancement of the chemical activity. Design of experiments (DOE) is a well-known statistical tool, which can assist in selecting optimized conditions and in obtaining systematic data. However, full factorial design requires a large number of experiment. Taguchi method is based on the use of an Orthogonal Array (OA) to evaluate optimization of the selected factors but with less required experiments. In this study, three factors, each on 2 levels, were selected: ball to powder ratio (B/P) with level 3 and 25, time of grinding with level 5 and 20, and water to powder ratio (W/P) with level 0 and 1. The degree of amorphization (DOA) was selected as the main response for the Taguchi method. DOA was calculated as the ratio between the integral intensities of the main peak of the kaolinite [001] before and after grinding. For dry grinding, the predicted optimized value of DOA complied with the experimental results. Maximized DOA value was achieved for B/P equal to 25 and the grinding duration of 20. This method can be a valuable tool to predict the amorphization degree of minerals present in the natural clay, leading to the optimization of the mechanical activation process.

Self-Cleaning of Photocatalytic Mortar with Glass Aggregate and Calcium Sulfoaluminate-Belite Cement

2019 ◽  
Vol 2673 (11) ◽  
pp. 704-715
Author(s):  
Aniruddha Baral ◽  
Jeffery R. Roesler
Keyword(s):  
Fly Ash ◽  
Surface Characteristics ◽  
Cementitious Materials ◽  
The Self ◽  
Fine Aggregate ◽  
Cleaning Efficiency ◽  
Solution Ph ◽  
Calcium Sulfoaluminate ◽  
Self Cleaning ◽  
Belite Cement

The self-cleaning performance and mechanism of photocatalytic mortars with different cementitious materials and aggregates was evaluated through a rhodamine B (RhB) degradation test. The self-cleaning property of photocatalytic concrete helps to preserve its aesthetics, NOx removal potential, and surface reflectance. In this study, the addition of TiO2 to calcium sulfoaluminate-belite cement (CSAB) demonstrated a self-cleaning potential like ordinary Portland cement (OPC). Photocatalytic mortar mixes with OPC demonstrated increased self-cleaning efficiency with glass fine aggregate and with higher TiO2 content. However, glass addition was not effective in improving the self-cleaning efficiency of CSAB mortar with TiO2. Replacement of OPC with class F fly ash significantly decreased self-cleaning efficiency. The decrease in pore solution pH with fly ash replacement of OPC or CSAB cement instead of OPC was hypothesized as the cause for the decline in self-cleaning efficiency. An experiment to study the photocatalytic degradation rate of RhB revealed that it increased with higher pH. RhB photocatalytically degrades through N-de-ethylation and cleavage of the chromophore structure depending on the reaction surface characteristics with the first path investigated in this paper. It was shown that some of the RhB on the photocatalytic mortar surface was degraded by the N-de-ethylation path regardless of the cement and aggregate constituents and increasing TiO2 (anatase) content increased RhB degradation through N-de-ethylation.

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