Self-cleaning Concrete Research Articles

Eco-Friendly Concrete Solutions: The Role of Titanium Dioxide Nanoparticles in Enhancing Durability and Reducing Environmental Pollutants - A Review

Concrete is one of the key components of construction, which ensures durability and aesthetics of the building. In recent days, nanoparticles are playing an essential role in civil engineering research. The binding of nanoparticles into concrete significantly improves the mechanical and durable properties due to the nanostructure of the cementitious materials. This review paper represents the existing research data on titanium dioxide nanoparticles, when applied in the different types of concrete. The data influenced by the different research papers are presented in terms of strength and durable parameters. The most important property of titanium dioxide nanoparticle is its self-cleaning effect because of the photocatalytic reaction is also discussed. The inference from the papers shows the effect of titanium dioxide nanoparticles on correct proportion enhances the production of new material with good strength and durable properties in the construction industry. The photocatalytic action of nano titanium dioxide leads to the manufacture of self-cleaning concrete which shields the surface from environmental pollutants.

Effect of Using Nano-TiO2 on the Rheological Properties of Cementitious Systems

Self-cleaning concrete (SCC) was developed that can reduce air pollution by utilizing its photocatalytic property. Due to this feature, polluting materials are broken down into H2O and CO2, which are completely harmless, without the need for any additional carrier gas. For this purpose, it was emphasized that semiconductor oxides with photocatalytic properties such as TiO2, ZnO, CdSe and WO3 are used in the production of SCC. Compared to other oxides, it was determined that nano-TiO2 is more commonly preferred. However, it was emphasized that the use of nano-TiO2 due to the high surface area/volume ratio increases the water requirement and the risk of agglomeration of cementitious systems. This situation directly affects the rheological properties of SCC. In this study, the effects of nano-TiO2 utilization ratio change on the rheological properties of cementitious systems were investigated. For this purpose, a total of 4 mixtures were prepared by substituting nano-TiO2 with 28 nm at a rate of 0, 0.5, 1 and 1.5% by weight of cement. The rheological properties of the prepared mixtures were evaluated according to the dynamic yield stress (DYS), apparent viscosity (AV) and structural build-up (Athix) parameters. It was understood that the DYS, AV and Athix values of the mixtures increased with the increase of nano-TiO2 utilization ratio.

Study on the Behavior of Self-Cleaning Impregnated Photocatalyst (Tio2) with Cement Mortar

Cement-based materials are increasingly and widely employed in infrastructure development; however, they pollute our environment by generating carbon dioxide, which is detrimental to our civilization. In self-cleaning concrete, photocatalysts accelerate the decomposition of organic particles; thus, photocatalytic degradation of gaseous pollutants could reduce pollution. The incorporation of photocatalytic components enhanced the mechanical self-cleaning properties of cement mortar. In this study, 4–6 percent by weight of rutile TiO2 was added to mortar, and the results were compared to those of a control sample. On the proposed mortar cubes, both fresh mortar and hardening mortar experiments were conducted. Because the initial and final setting times of TiO2 differ from those of conventional cement mortar, the surplus TiO2water-cement ratio had to be modified. The adaptability of the sol-gel method enables the use of various process parameters to influence the properties of the produced TiO2 nanoparticles. The compressive strength was calculated for 7, 14, 21, and 28 days, and an ultrasonic velocity test was performed after 28 days. On mortar samples, acid and sulfate attack experiments were performed. The M-3 mortar mixture containing 5% rutile exhibited the highest level of strength compared to the other mixtures. The M-3 exhibits a strength that is 10.96% greater than that of the control mix. The impact of acid and sulfate attack on the strength of mix M-2 is relatively modest in comparison to other mixtures. Using RhB (rhodamine color) discoloration under UV light, such as sunlight, the photocatalytic mortar is concentrated; a typical test for self-cleaning cementitious materials reveals the presence of more photocatalytic material, which yields the best results.

Experimental studies on Self-Cleaning Concrete by photocatalytic activity for rigid pavements

The environmental sustainability and sustainability of materials worldwide is the most concerning topic in the selection process of materials for construction. Self-Cleaning Concrete (SCC) consists of self-cleaning qualities and it is an environmentally friendly material. The main advantage of this new, modern composite helps in reducing maintenance costs along with a clean environment. This modern concrete removes dust and pollutants under UV rays of sunlight by photocatalytic action. In this study, M40 grade concrete was prepared conventionally and by the addition of Titanium dioxide (TiO2). TiO2 is added to concrete in amounts ranging from 0.5%, 1.0%, and 1.5% of the weight of cement. The compressive strength and flexural strength of concrete specimens of size 150mm X150mm X 150mm and 100mm X 100mm X 500mm respectively. Then the specimens were cured and tested for 7 and 28 days. The self-cleaning ability of SCC is investigated using methyl orange, methylene blue, and Spectrophotometer under UV light or sunlight

Analyzing the Effects of Nano-Titanium Dioxide and Nano-Zinc Oxide Nanoparticles on the Mechanical and Durability Properties of Self-Cleaning Concrete.

The goal of this paper is to investigate the impact of nano-materials on the mechanical and electrochemical properties of self-cleaning concrete. Nano-titanium dioxide and nano-zinc oxide were used as additives for this purpose. Additionally, a comparative study on the effect of using these materials on the self-cleaning concrete's characteristics was conducted. The dosages of nano-titanium dioxide (nps-TiO2) and nano-zinc oxide (nps-ZnO) used were 0, 0.5, 1, 1.5, 2, and 2.5% and 0, 1, 2, and 3% of the weight of the cement, respectively. The results showed that the optimum compressive strength and the lowest corrosion rate were fulfilled at 2.5% of nps-TiO2 and 1% of nps-ZnO, and using 2.5% of nps-TiO2 achieved the highest improvement in the corrosion rate. However, 1% for nps-TiO2 mixtures and 1% for nps-ZnO mixtures were the best ratios for flexural strength. On the other hand, for the corrosion rate, the samples were tested at 2 and 6 months. When nps-TiO2 and nps-ZnO samples were compared to the control sample, 2.5% and 1% of nps-TiO2 and nps-ZnO, respectively, showed the largest improvement in resistance to corrosion. Also, the self-cleaning property of the samples containing nano-materials (nps-TiO2 and nps-ZnO) was tested. As the results illustrated, the self-cleaning property of the samples was increased over time due to photocatalytic degradation. Furthermore, the results of the photocatalytic tests showed that nps-TiO2 samples outperformed nps-ZnO samples overall.

Total recycling of concrete waste using accelerated carbonation: A review

Our world is facing critical environmental challenges due to the overexploitation of natural resources and the extensive release of CO2. Meanwhile, huge amounts of concrete waste are generated due to accelerated urbanization and redevelopment. Carbonated concrete waste can thus both be used as alternative materials to aggregates and cement, and a carbon sink to reduce CO2 emission. In this paper, different carbonation approaches and their modified techniques to treat recycled coarse aggregates (RCAs), recycled concrete fines (RCFs), and recycled concrete powders (RCPs) are critically reviewed and discussed. The results suggest that carbonation effectively strengthens RCAs by densifying microstructures and improving physical properties through the precipitation of calcium carbonate (Cc) that fills the pores. Meanwhile, the carbonation reaction also develops surface reactivities on the recycled aggregates due to silica gel and Cc formation, which is particularly beneficial for RCFs because of the high surface area. Re-structuring and re-activation of RCPs through carbonation transforms the waste hydrated cement powders into novel supplementary cementitious materials. In addition to wet carbonation, which has a higher efficiency than dry carbonation, other modified carbonation techniques with the addition of limewater, magnesium ions, ammonium ions, and the use of elevated temperatures are found to produce RCAs/RCFs/RCPs with better qualities, and facilitate the formation of other high-value products such as nano-silica gel, micro-fiber, and vaterite, etc. Apart from their practical uses in conventional concrete, potential applications of the carbonation products in ultra-high-performance concrete, automated construction, and self-cleaning concrete were also briefly introduced. More importantly, the key issues in upscaling the carbonation technologies and limitations in current research are pointed out. Overall, carbonation could not only facilitate the re-circulating of concrete waste but also help reduce CO2 emissions and achieve carbon neutrality by permanently sequestrating CO2.

Utilizing Stearic-Acid-Coated Marble Dust for the Production of Eco-Friendly Self-Cleaning Concrete: RSM Modeling and Optimization

With the growing demands of the construction industry, the need for manufacturing cement increases, and it causes challenges to the climate as one ton of cement results in the release of around one ton of CO2. Therefore, it is essential to find an alternative to reduce the environmental impact. This study aims to optimize the properties of concrete containing marble dust and stearic acid to produce eco-friendly and self-cleaning concrete. Stearic acid induces a self-cleaning property in concrete to make it free from moisture, leading to its prolonged service life. Thirteen mixes are designed, using marble dust as a partial replacement of cement by weight (at 10%, 20%, and 30%) and stearic acid by cement weight (at 0.5%, 1%, and 1.5%) in this eco-friendly self-cleaning concrete. Nine mixes were developed using response surface methodology (RSM), where two variable inputs were considered. The compressive, tensile, and flexural strengths were assessed. Other tests such as ultrasonic pulse velocity, Young’s modulus of elasticity, density, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and self-cleaning property have been conducted and evaluated. At 10% replacement of marble dust by the weight of cement and with a 0.5% coating of stearic acid, the compressive, tensile, and flexural strength of concrete increases by 12.68%, 21.71%, and 16.73% over the control mix, whereas the best self-cleaning property is observed at 30% partial replacement of cement with marble dust coated with 1.5% of stearic acid.

Effect of industrial wastes on self-cleaning properties of concrete containing anatase-TiO2

Concrete decomposing the organic compounds on because of natural or anthropogenic contaminating sources with photocatalysis existing in its structure is called self-cleaning concrete. In this study, the self-cleaning concrete with industrial waste has been searched from the point of mechanical and physical characteristics. Fly ash, blast furnace slag and sepiolite materials has been used as industrial waste in concrete. Titanium dioxide (TiO2) has been used as photocatalysis material. Specimens with the dimensions 15×15×15 cm were produced using 0 %, 10 %, 20 % and 30 % industrial wastes and 0 %, 1 %, 3 %, 5 % TiO2 by weight instead of cement. Compressive strength, unit weight, and ultrasonic pulse velocity tests were performed on the specimens after 28 days standard cure. Rhodamine-B test in Italian UNI 11259 standard and additional Phenantroquinone test have been performed as self-cleaning test. XRF test also has been made on some of the samples for the chemical analysis. The best photocatalysis performance has showed in the concrete including 5 % TiO2. Test results show that 10 % use of industrial wastes in self-cleaning concrete production is recommended from the point of economic and environmental benefits

Titanium dioxide as a photocatalyst to create self-cleaning concrete

The use of Titanium Dioxide (TiO2) in the form of Ultrafine particles as a coating for concrete pavement have received considerable attention in recent years as these particles can trap anti compose organic and inorganic air pollutant by photocatalytic process. In spite of these promising benefits, durability and resistance to wear a of Titanium Dioxide (TiO2) coatings has not been evaluated. The objective of this study is to determine photocatalytic effect on concrete with spectrophotometer and its effect on environment. We prepared samples of varying % of TiO2 and checked the effect on its strength, and its ability to resist the radiations and compared their results with normal concrete.

Utilization of ecofriendly self-cleaning concrete using zinc oxide and polypropylene fibre

Self-cleaning concrete is also known as air purifying concrete. The main action of this concrete is to purify the indoor air pollutants inside the concrete and create ecofriendly environment. It is harmless to use and absorb the UV radiation reduce the harmful gases entering inside. Adding photocatalytic zinc oxide create an absorbent layer inside the concrete due to this formation we can reduce the smoke, harmful gases entraining agents. The approach of concrete is carried by the presence of sunlight to reduce air pollutants. Photo catalytic activity will not affect the nature of the concrete and its properties. In this study the strength of concrete is determined by photocatalyst zinc oxide and polypropylene fiber. The photocatalytic behavior is treated by coating indigo dye under UV exposure in concrete specimen.

Photocatalytic Self-Cleaning Fine-Grained Concrete

Photocatalytic Self-Cleaning Fine-Grained Concrete

Simple Fabrication of Concrete with Remarkable Self-Cleaning Ability, Robust Superhydrophobicity, Tailored Porosity, and Highly Thermal and Sound Insulation.

Self-cleaning materials have attracted immense commercial and academic interests in recent years. A major challenge is the scalable and cost-effective fabrication of three-dimensional bulk materials with remarkable self-cleaning and a desirable combination of tailored porosity, robust superhydrophobicity, excellent mechanical strength, heat insulation, and sound absorption ability. Here, self-cleaning concrete was achieved in one step through the combination of the liquid template pore formation and in situ bulk hydrophobic modification. The concrete exhibited superhydrophobicity with a high water contact angle of 166° both on the surface and inside of the sample, which qualified the sample with remarkable stain repellency and long-term stability. The water contact angle remained unchanged under continuous mechanical grinding and harsh environments, such as high temperature (450 °C in air and 650 °C in Ar) and chemical erosion. The concrete with a controllable porosity from 56.3 to 77.4% and homogeneous small pore size (∼15 μm) exhibited high compressive strength and low thermal conductivity. Furthermore, high sound absorption capacity (97%, 500 Hz) at a vibration frequency from 400 to 600 Hz was realized. With these excellent performances and characteristics and easy scalable fabrication, the concrete prepared in this work possessed a wide application prospect.

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

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.

Self-Cleaning Concrete for Landscaping Applications

Negative effects of environmental pollution pose a significant risk to agriculture, water resources and human health. This can however be reduced by selecting appropriate materials in construction and landscape architecture. It is well-known that strong sunlight or ultraviolet light decomposes many organic materials in a slow natural process. Photocatalytic substances accelerate this process and when used in concrete (which is one of the most widely used construction materials), permit the treatment of pollutants close to their source by applying a self-cleaning principle: decomposing organic materials, biological materials and pollutants into molecules like oxygen, water, carbon dioxide, nitrates, and sulphates. Catalytic material activation will start due to energy that is received from sunlight (it also can be activated using artificial lights), and self-cleaning begins when this material is activated. Beside other properties, this innovative self-cleaning concrete also keeps its colour for far longer than other traditional building materials, making it a desirable solution for landscaping applications.

Study on Self-Cleaning Concrete Using Nano-liquid TiO2

The present work explores to study the compressive strength and self-cleaning properties of the concrete by the applications of nano-liquid TiO2 on fresh concrete with different dosages (0, 2.5, 5.0, 7.5 ml) and single, double, and triple layer coating of nano-liquid Tio2 on the hardened concrete surfaces. Cement was partially replaced with Fly ash by In this study cement was replaced with 30% fly ash and to examine self cleaning properties of concrete by using Rhodamine-B dye (RhB) discoloration test under Sunlight/UV light visual observation. Concrete samples with photocatalytic nano-liquid Tio2 was mixed with fresh concrete (NF) showed enhanced compression strength by increasing the dosages when compared to the nano-liquid Tio2 was coated on the surface of the hardened concrete (NH). Self cleaning ability of NH of samples showed better results in cleaning ability than NF samples.

Review on Characterization and Mechanical Performance of Self-cleaning Concrete

Self-cleaning concrete is an effective alternative to provide cleaner environment which contribute to sustainability and towards a green environment. It is in accordance with the requirements of environmental issues on huge energy consumption and air pollution from carbon dioxide (CO2) emissions. Photocatalyst in self-cleaning concrete accelerates the decomposition of organic particulates, hence pollution could be reduced through photocatalytic degradation of gaseous pollutants. Mechanical performances of self-cleaning concrete were improved by adding photocatalytic materials. Self cleaning abilities were evaluated in the photocatalytic activity test under UV light and photocatalytic degradation of gaseous pollutant was measured by depollution test. This review aims to give an overview about the characteristics of photocatalytic materials and mechanical performances of self-cleaning concrete.

APPLICATION OF EXPOSED CONCRETE AT ERECTION OF MONOLITHIC BUILDINGS

In the present paper, we consider improvement of the cast-in-place construction technology with the application of exposed (architectural) concrete, which allows implementing the boldest ideas of architects directly on a construction site, transforming cast reinforced concrete into the category of architectural front surface. We also consider the perspectives of the technology development in Russia and abroad. We show the examples of the exposed concrete designs implemented in the European countries. We give a description to the technology of exposed concrete; define the concepts of “exposed” and “self-cleaning” concrete. In addition, we consider the advantages of exposed concrete, the content, kinds, purpose and technical characteristics of architectural and self-cleaning concrete, as well as the factors influencing the result of concreting when using this technology.

Self-cleaning geopolymer concrete - A review

Concrete is the most widely used construction materials for building technology. However, cement production releases high amounts of carbon dioxide (CO2) to the atmosphere that leads to increasing the global warming. Thus, an alternative, environmental friendly construction material such as geopolymer concrete has been developed. Geopolymer concrete applies greener alternative binder, which is an innovative construction material that replaces the Portland cement. This technology introduced nano-particles such as nanoclay into the cement paste in order to improve their mechanical properties. The concrete materials also have been developed to be functioned as self-cleaning construction materials. The self-cleaning properties of the concrete are induced by introducing the photocatalytic materials such as titania (TiO2) and zinc oxide (ZnO). Self-cleaning concrete that contains those photocatalysts will be energized by ultraviolet (UV) radiation and accelerates the decomposition of organic particulates. Thus, the cleanliness of the building surfaces can be maintained and the air surrounding air pollution can be reduced. This paper briefly reviews about self-cleaning concrete.

Preparation of titanium dioxide nano particle modified photocatalytic self-cleaning concrete

The self-cleaning concrete is a potential approach to make the city cleaner by reducing the air pollutants. In this study, a photocatalytic concrete with ultra-smooth surface was fabricated with a new approach taking use of the nano granular nature of the main hydration product of cement i.e. Calcium Silicate Hydrates (C–S–H) and the photocatalysis properties of TiO2 nano particles. Results show that the surface of the fabricated concrete was covered by C–S–H and TiO2 nano particles around tens of nm; the surface roughness of the concrete was 3.5–11 nm; the surface of the photocatalytic ultra-smooth concrete can degrade methylene blue (MB) effectively. Due to its ultra-smooth surface and photocatalytic properties, the residue of contaminants will be washed away by the rain, this new type of concrete is promising to be utilized as a self-cleaning finishing material for the urban buildings.

Superhydrophobic concrete surfaces with integrated microtexture

Ultra-High Performance Concrete (UHPC) is characterized by a densely packed mix-design, which can offer attractive surface properties for architectural building facades. A technical challenge for aesthetic applications is the protection against fouling. This work demonstrates that water-repellent concrete can be obtained just after demoulding by replicating the features of micro-pillared moulds made of polydimethylsiloxane (PDMS). Moreover, the negative replica of the microtextured UHPC surface can be used as a master to template for other UHPC samples, constituting a cost-effective route to fabricate large-scale microtextured concrete pieces. The chemical functionalization of UHPC with a low surface energy material is obtained by transferring residues from the PDMS mould or by spraying siloxane-based compounds to form a homogenous surface film. The latter preparation method showed superhydrophobic properties with static contact angles reaching up to 164° and contact angle hysteresis reaching as low as 2.5°. This process enables the manufacture of water-repelling, self-cleaning concrete. Raindrops slide off the concrete surface, carrying debris away.