Porous Tiles Research Articles

Innovative ceramic pigments from recycled lithium-ion battery cathodes for inkjet applications

The booming of the electric mobility together with the need of storing renewable energies have increased the demand of lithium-ion batteries which will bring about increasing amounts of electronic waste. Besides, the need for alternative sources of certain raw materials considered critical has changed the perception of determined wastes, which are no longer considered residues but sources of raw materials. In this work, the active cathode material present in end-of-life lithium-ion batteries (Ni, Co, and Mn) was used as secondary raw material, after being properly separated, in the synthesis of a cobalt iron nickel manganese chromium black spinel ((Co, Fe, Ni, Mn) (Fe,Cr)2O4). The pigment was used in the formulation of a ceramic inkjet ink which was deposited over a single-fired porous tile and porcelain tile. Texture and brightness of the ink were not affected by the use of this waste, thus presenting excellent prospects for the industrial ceramic application.

The rooftop cooling potentials of evaporative cooling porous tiles and high reflective coatings in hot and humid regions

Altering the reflectivity and permeability of surfaces in high-density cities is a key approach to mitigate rising urban heat islands. High Reflectance Coatings (HRC) and Evaporative Cooling Porous Tiles (ECPT) offer potential solutions for urban cooling. However, previous studies have mainly focused on roof surface temperatures, neglecting changes in near-roof air temperature. ECPT, a new permeable material, is mostly used in urban pavements and ignoring the underutilized rooftops, with limited research on its cooling effects in these settings. Therefore, this study investigates the impact of HRC and ECPT on near-roof air temperatures in the Pearl River Delta through observational experiments under various weather conditions. The results show that both HRC and ECPT significantly reduce near-roof air temperatures, but their effectiveness decreases above 1.8 m. In rainy conditions, these strategies are less effective due to their dependence on solar radiation. HRC works by reflecting short-wave radiation, while ECPT cools by evaporation. A key advantage of ECPT is its ability to be actively watered, quickly reducing temperatures by 2.14 °C at 0.3 m. This research is valuable for developing urban cooling strategies in high-density areas during extreme temperature conditions.

Light-weighing traditional ceramics by porosity control and consequences on mechanical strength

This work evaluates the impacts of the addition of cellulose fibres (5 and 10 wt%) and pumice powder (5 wt%) as pore forming agents on the porosity, microstructure and mechanical strength of two traditional ceramic compositions: stoneware and terracotta. Open and closed porosities, pore size distribution and morphology were obtained from the combined use of the Archimedes method, mercury intrusion porosimetry and SEM image analyses.The results show an increase in the open porosity ratio in the case of cellulose fibre addition, whereas pumice powder addition promotes an increase in the closed porosity. The addition of cellulose also modifies the pore morphology of stoneware samples and induces a pore size increase. The decrease in mechanical strength caused by a lower firing temperature is greater than the decrease linked to the porosity generated by pore-forming agent addition. As the moduli of rupture of the produced porous tiles are higher than those needed by the standards, this work proposes new opportunities for lightning ceramic products.

Experimental analysis of airflow uniformity and energy consumption in data centers

Temperature and airflow uniformity are experimentally investigated in this research study along with energy consumption analysis on the laboratory container size small data center. A raised floor plenum (RFP) data center system of size 6 (L) × 3.1 (W) × 2.3 (H) m with one Computer Room Air Handler (CRAH), two rows and each row contains five racks, five 8U simulator cabinets in each rack was constructed to test partial and closed cold aisle containment (CAC). Seven different cases were investigated with variables of perforated tiles (32%, 50 % & 70%), CRAH fan speed (60 Hz, 42 Hz), chiller return water temperature (CRWT) (15 °C & 17 °C) and heating load (full 50 kW, 75% load 37.5 kW). These cases were further analyzed using Rack Cooling Index (RCI) and Supply Heat Index (SHI) along with power consumption scenarios in terms of Coefficient of Performance (COP) and Power Usage Effectiveness (PUE). The uniqueness of this study is experimental investigations of system COP and PUE analysis for a wide range of important variables for partial and closed CAC. It was found that 50% porous tile provided the best airflow and temperature uniformity for the case of partial containment with full and 25% reduced heat load along with full and 30% reduced CRAH speed respectively. Slight recirculation was observed during the reduced CRAH fan speed case at the corner edge of data racks. However, due to additional supply airflow usage, these recirculation’s were within the acceptable SHI. Reduction of CRWT reduces the total Heating Ventilation and Air Conditioning (HVAC) power consumption and improves the overall system COP.

UV laser sterilization of Bacillus atrophaeus spores on ceramic tiles

Ultraviolet (UV) radiation is one of the most common methods for sterilizing materials with suspected biological warfare agent contamination. In this study, UV laser sterilization of ceramic tiles was investigated as a method for destroying Bacillus atrophaeus spores. The effects of UV irradiation were evaluated as a function of water absorption (porous and vitrified), tile color (black and white), and surface brightness (matte and glossy). Spores were loaded onto the surface of each tile and irradiated with a 266-nm UV laser. The irradiated spores were then removed by scraping with a razor blade and cultured in an agar plate for 24 h. The sterilizing effects of the UV laser were greater on the vitrified (group BI b ) tiles than on the porous (group BIII) tiles. In addition, sterilization was more effective on white and matte tiles than on black and glossy tiles, respectively.

Synthesis of wollastonite from diatomite-rich marls and its potential ceramic uses

This paper describes the laboratory process of synthesis of wollastonite based on calcining at 1050°C a diatom-rich marl from waste tips of diatomite deposits of Hellín (Albacete. Spain) and its potential use in porous white-ware. The results show that it is viable to obtain wollastonite using as a source rock diatom-rich marls from a natural deposit and that the use of this synthetic material in the compositions for white-ware porous tiles substituting calcium carbonate or natural wollastonite, has not only produced viable products, but has greatly reduced the firing temperature of the raw mixes.

Evaluating the use of steel scrap, waste tiles, waste paving blocks and silica fume in flexural behavior of concrete

Steel scrap is a waste product of steel plate manufacturing industry. A large quantity of steel scrap is produced by drilling every year. The disposal of those steel scraps is a major issue in Iraq and all over the world. The landfill is one of the methods for disposing the scraps albeit it produces soil pollution. What is worse is that in Iraq there is no waste separation system in a sense that all the waste materials are dumped in soil especially in the desert, and it is harmful to the environment. One way to alleviate the situation, the present study suggests that steel scrap is added with concrete, and the mechanical and physical properties were studied. Waste materials, such as terrazzo tile and paving block, are dumped in landfills. Such action destroys the environment. Recycling these materials and using them as fine and coarse aggregate in new concrete mixes would eliminate the problem. Additionally, these waste materials are considered as non-degradable. Silica fume has been employed as a partial replacement by weight of cement at percentages of (8%, 12%, and 16%) to enhance the concrete that contains the waste materials. This paper examines the workability of addition of steel scrap to the weight of concrete by the percentages of (0.6%, 1.2%, and 1.8%) as well as the addition of porous tile and paving block as partial substitute by percentages of (15%, 30%, and 45%) for coarse and fine aggregate, respectively. Concrete samples were produced and subjected to compression strength, water absorption and split tensile tests. A reduction in strength was observed for all concretes that contain porous tiles waste as the percentage increased, in relation to the control concrete. On the other hand, concrete that contains waste paving blocks shows an increment in strength at the percentages of (15% and 30%) and reduction at the percentage of 45%. Based on the compressive strength test results, steel scrap samples being at 0.6%, 1.2%, and 1.8% show that the strength increased of the samples with 0.6% and decreased of those at 1.2% and 1.8%. Thus, this research demonstrates that the use of three waste materials-crushed tiles waste, steel scraps and paving blocks waste as components of concrete is technically feasible in the manufacture of concrete.

Синтез новых негорючих теплозащитных материалов и исследование их свойств

Цель. Разработка новых огнестойких теплозащитных материалов, повышающих энергоэффективность и пожарную безопасность зданий и сооружений.
 Результаты. Разработаны новые составы пористых плиточных материалов на основе минерала доломита, стандартного натриевого жидкого стекла и минеральных кислот, с добавлением органических наполнителей. Исследования пожарно-технических характеристик полученных материалов, таких как горючесть и коэффициент дымообразования, показали их негорючесть.
 Область применения исследований. Представленные результаты исследований в области синтеза новых пористых материалов и могут быть использованы в области повышения огне- и теплозащиты строительных конструкций.

A novel protocol for producing low-abundance targets to characterize the sensitivity limits of ignitable liquid detection canines

Ignitable liquid detection canines have an extraordinarily sensitive sense of smell. Previous studies estimating canine sensitivity to ignitable liquids have been unable to demonstrate a level below which canines will not indicate ignitable presence. Forensic laboratories provide corroborating evidence and explain reasons for canine indications. Laboratories provide protection against false-positives and greater context for the exhibit contents to both investigators and the courts. However, the methods routinely used in forensic laboratories lack the sensitivity required to match canine sensitivity estimates, leading to frustration when canines provide a strong indication, but the laboratory findings are negative. In order to develop a laboratory method that can match the sensitivity of canines to trace ignitable liquids, an estimation of canine sensitivity is required. We present a protocol for producing extremely clean, porous tile substrates, and a scheme for quantitatively producing target samples with any desired abundance by using a solvent that does not elicit a response from the canines. Search experiments with two canine-handler teams validate the methods and provide the first estimate of the ignitable liquid detection canine sensitivity limit for gasoline: both canines repeatedly located gasoline at 5 pL but provided no indication at any level ≤3 pL. The protocol allows standardization of substrates and targets for canine olfactory testing, while the estimated canine sensitivity to gasoline provides a preliminary target for forensic laboratories performing confirmatory analysis on exhibits selected by ignitable liquid detection canines.

Understanding the water absorption from MHEC modified glue mortar into porous tile: Influence of pre-drying

This article presents an experimental investigation on the influence of Methylhydroxyethylcellulose (MHEC) modified mortar on water absorption into tile and base substrate using Nuclear Magnetic Resonance (NMR) imaging. Addition of MHEC shifts the absorption behavior from homogeneous to inhomogeneous as a result of increased viscosity of pore solution. The observed reverse flow from tile to mortar is a result of decrease in capillary pressure in mortar as a consequence of decrease in pore size due to hydration. Pre-drying of 1.3 wt% MHEC mortar with dry air shows little wetting by tile due to MHEC transport and formation of dry region at the mortar surface. On the contrary, pre-drying of 1.3 wt% MHEC mortar at 40% RH slows down MHEC transport and delays the formation of dry region at the mortar surface enabling higher wetting by tile.

Evaporative cooling of porous tiles with seawater in a tropical climate with salty humid air

Buildings on tropical islands in the South China Sea are facing an overheating challenge. High-water-absorbency unglazed porous ceramic (UPC) materials could counteract heat gain by evaporation. Salty humid air and seawater in the marine environment lead to evaporative cooling differences from inland conditions. This research replicated a salty humid atmosphere with a stable concentration similar to the actual environment in a dynamic hot-humid climate wind tunnel (DHWT). The influence of salt in gas-liquid media on evaporative cooling is discussed. The results showed that the salt concentration of humid air in the wind tunnel can be controlled by adjusting the atomization rate and the concentration of the atomized liquid. Humid air and liquid with salt reduced the evaporation rate of the UPC tiles. The influence of salty humid air was generally less than that of seawater. In 6 mg/m3 salty air, the total evaporative cooling effect decreased by 2.63% and 40.44% when saturated with fresh water and a 3.5% sodium chloride solution, respectively, relative to saturation with fresh water and evaporation in humid air without salt. In conclusion, sea salt in humid air and in the liquid phase reduced but did not eliminate the evaporative cooling effect of UPC materials. Seawater source utilization showed a significant benefit in cooling and water conservation aspectsin coastal areas.

Impact of climatic factors on evaporative cooling of porous building materials

The evaporative cooling of porous building materials is one of the passive strategies used for building energy conservation. The effect of evaporative cooling strongly depends on the evaporation rate, which is defined as the mass of water evaporated from a unit area of a porous material per unit time. In contrast to previous studies, which focused on the influence of material properties on the evaporation rate, the present work investigates the effects produced by climatic factors. In particular, porous clay tiles with pore sizes of 2.0–6.0 µm and porosity of 27.34% were selected as water storage media, and the impacts of four climatic factors (air temperature, solar radiation intensity, wind velocity, and partial pressure of water vapour) were examined at three different levels. The obtained results indicate that the evaporation process from porous tiles consists of constant evaporation rate, falling evaporation rate, and low evaporation rate stages. Moreover, by conducting range analysis, the studied factors can be ranked by their impact on the evaporative cooling process as follows: the intensity of solar radiation, air temperature, partial pressure of water vapour, and wind velocity.

Evaporation of the Nerve Agent GB From Common Matrices: A Model‐System Study

The measurement of a temperature‐dependent volatilization rate of the nerve agent GB (sarin) from various common matrices, using a laboratory‐designed wind tunnel (model system), is described. Small GB droplets are dispersed on the matrices surfaces, and samples are collected from the model system and analyzed utilizing a solid phase extraction/gas chromatography analytical method. Profiles demonstrating the vapor concentrations as a function of time are calculated. The results indicate that asphalt blocks relatively conserve GB, exhibiting a slow‐release mode of action over at least 2 weeks. Nevertheless, using standard decontamination procedures such as super tropical bleach may prevent this secondary evaporation risk. The concentration profile of commercial sidewalk bricks show a moderate decay, probably due to the existence of basic sites in the cement‐containing bricks. Fast clearance of GB is measured from smooth surface tiles, as these porous tiles both adsorb and/or degrade GB droplets very quickly.

The impact of evaporation from porous tile on roof thermal performance: A case study of Guangzhou’s climatic conditions

The evaporative-cooling roof is a popular passive energy conservation technique. This article presents a novel approach for modelling and analysing the influence of evaporation on roof thermal performance. A multivariate nonlinear model was developed for the prediction of the evaporation rate from porous tile. A computer program was then developed based on the one-dimensional roof unsteady heat transfer theory. Finally, the computer program and hourly weather data of Guangzhou, China, were used to analyse the impacts of evaporation (including the evaporation start time and water-application frequency) and slope orientation on roof thermal performance. Evaporation beginning at 11:00 can reduce the external surface temperatures of a horizontal roof and 30°-inclined east-sloping and west-sloping roofs by up to 11.3, 10.7, and 9.8°C, respectively, from those of a non-evaporative roof. This, in turn, can reduce the peak-hour (16:00–20:00) internal surface heat flux. Additionally, with the horizontal roof, the reduction in the peak-hour heat flux can be doubled if the evaporative layer is frequently replenished with water.

Reusing ceramic tile polishing waste in paving block manufacturing

Ceramic companies worldwide produce large amounts of polishing tile waste, which are piled up in the open air or disposed of in landfills. These wastes have such characteristics that make them potential substitutes for cement and sand in the manufacturing of concrete products. This paper investigates the use of ceramic tile polishing waste as a partial substitute for cement and sand in the manufacturer of concrete paving blocks. A concrete mix design was defined and then the sand was replaced with wastes from three production lines (porcelain tile, porous tile and stoneware tile) of a Brazilian ceramic tile industry in the percentages of 5%, 10%, 15%, 20%, 25% and 30%. Another group of concrete was produced with porcelain tile waste replacing the cement. The concretes were characterized using a slump test. Paving blocks were produced and subjected to compression strength, water absorption and porosity tests. Compression strength values were compared to Brazilian Standards for paving blocks. A reduction in slump was observed for all concretes as the percentage of waste addition increased, in relation to the control concrete. The compression strength values were higher for concrete cured for 28 days, and all blocks met the standard requirement of 35 MPa for light vehicle traffic at a curing age of 7 days. The strength values obtained when the porcelain tile waste replaced sand were higher than when this waste replaced cement, and those values were even higher than the control concrete, and met the standard requirement of 50 MPa for heavy vehicle traffic. Water absorption values tended to decrease as sand was replaced by ceramic tile wastes, due to the filler effect. These results show that it is possible to replace 30% of fine aggregate or 20% of cement with ceramic tile wastes and produce paving blocks suitable for use in heavy vehicle traffic. Thus, this research demonstrates that the use of ceramic tile waste as a component of concrete for paving blocks manufacturing is technically feasible.

Study of Residual Stresses in Traditional Ceramics

Residual stresses in traditional ceramics may have different origin and nature. In glazed tiles (both porous and sintered), they can be due to the thermal expansion mismatch of glaze and body. Another type of residual stresses in glazed and unglazed porcelain tiles is due to temperature gradients during cooling, which give rise to volume variations in different areas of the same ceramic ware. Thermal gradients may originate not only between the surface and the core of the tile, but also between the upper and the lower face of the tile. The common practice in the porcelain tile industry to use differential cooling to control the planarity of the finished product induces permanent changes of volume in different areas of the ceramic ware, which give rise to permanent states of stress. At room temperature there are two main stress relaxation mechanisms, depending on the nature of the tiles: cracks growth in porcelain tiles and post-expansion in porous tiles. Generally, residual stresses relaxation cause delayed curvature according to these different mechanisms. Optical dilatometry and optical fleximetry techniques allow to investigate the volume changes induced by the cooling rate and the glaze-body coupling, factors responsible for residual stresses.

Clays and bodies for ceramic tiles: Reappraisal and technological classification

The ceramic tile industry is a dynamic sector whose technological innovation and market trends have drawn a complex picture of products and processes. Raw materials have been deeply involved in such an evolution: the flexibility of current manufacturing cycles enables the use of a very wide range of clays, whose chemical and mineralogical composition, particle size distribution and ceramic properties were reappraised. The classical reference schemes are no longer able to properly describe and predict the role of clays in tilemaking. In order to fill this gap, an industry-oriented, technological classification of clay raw materials is proposed on the basis of chemical (Fe2O3 content) and mineralogical parameters (amount of phyllosilicates and carbonates) together with particle size (fractions <2μm and >63μm) and plasticity (methylene blue index and Atterberg plastic index). It firstly discriminates light-firing and dark-firing clays according to an iron oxide threshold of 3%. Light-firing clays are distinguished by the amount of kaolinite group minerals and plasticity in “kaolins” (high-grade, low-grade, and raw kaolins, kaolinitic loams) and “plastic clays” (ball clays, pyrophyllitic clays, white bentonites); the distinction of three classes of ball clays with increasing plasticity is envisaged. Dark-firing clays are classified according to coarse-grained fraction and amount of carbonates in carbonate-rich types (marly and carbonatic clays), red loams and red clays; these latter are furtherly differentiated by the relative abundance of clay minerals. Such a classification is essential to draw the guidelines for body formulation and to explain the criteria followed in the industrial practice for each category of ceramic tiles. Key properties are discussed to design batches for porous tiles, vitrified and semi-vitrified red stoneware, and vitrified light-firing bodies. Both the clay classification and the guidelines to body formulation are intended to provide up-to-date tools to assess the ceramic potential and correct use in tilemaking of clay materials, but they cannot substitute a throroughful technological characterization, adequately simulating the industrial processing.

Heating Transformations, Technical Properties and Ceramic Suitability of Clays

Heating transformations of calcareous chloritic-illitic and carbonate-free kaolinitic-illitic raw clays, and their mixes were investigated in the range of 700°-1060°C using X-ray diffraction, thermal analyses and scanning electron microscopy. Moreover, changes of bending strength, shrinkage and water absorption versus temperature and clay content were followed. The results showed that plagioclase and sanidine together with spinel formed and persisted in fired calcareous and non-calcareous clays respectively. In fired clay mixtures only plagioclase occurred. Formation of the latter phase was discussed using CaO-SiO2-Al2O3 equilibrium diagram. The intensification of the neoformation processes due to the increase of temperature together with melt formation mainly in carbonate-free clay improved the ceramic properties to certain extent. Improvement of the mechanical strength was also observed for mixture of clays. The reported diagrams, involving grain size distribution and chemical composition, showed that both clays and their mixtures could be suitable for porous tiles or lightweight ceramic blocks manufacturing.

Development of High-Strength Porous Tiles Produced by Recycling Glass Fibers in Waste GFRP

Development of High-Strength Porous Tiles Produced by Recycling Glass Fibers in Waste GFRP

OS3-9 廃棄GFRPを再利用した高強度多孔質タイルの開発 : タイルの製造条件について(OS3-II 材料の性質評価)

OS3-9 廃棄GFRPを再利用した高強度多孔質タイルの開発 : タイルの製造条件について(OS3-II 材料の性質評価)