Ceramic Building Materials Research Articles

Synthesis of neutral SiO 2 /TiO 2 hydrosol and its photocatalytic degradation of nitric oxide gas

A neutral transparent SiO 2 /TiO 2 composite hydrosol was prepared by a coprecipitation-peptisation method using titanium tetrachloride and SiO 2 hydrosol as raw materials. The prepared SiO 2 /TiO 2 hydrosols were characterised by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. The evaluation of photocatalytic activity for nitric oxide degradation showed the optimal weight ratio of SiO 2 /TiO 2 is around 1.5. After heating at 700°C for 1°h, the prepared SiO 2 /TiO 2 hydrosol exhibits much higher photocatalytic activity than the commercial TiO 2 materials, Degussa P25 and ONID TH. The presence of Ti-O-Si bond in the composite hydrosol results in its good thermal stability. The prepared transparent SiO 2 /TiO 2 hydrosols were stable without agglomeration or gelation after storage at room temperature for over 1.5 years. The neutral SiO 2 /TiO 2 hydrosol could be used as the coating material applying for glass or ceramic building materials which must be treated at high temperature.

Ceramic building materials for electromagnetic interference shielding using metallurgical slags

The technological properties and the electromagnetic shielding efficiency of clay based ceramic building products prepared by using electric arc furnace slag (EAFS) and ladle furnace slag (LFS) as admixtures and fired at various temperatures were investigated. Chemical and mineralogical analyses were performed to characterise EAFS and LFS. The results showed that the ceramic specimens prepared by the addition of EAFS to the clayey material presented better shielding efficiency than the relevant of LFS, both tested in the same X-band frequency range (8–12 GHz). The prepared specimens showed water absorption, flexural and compressive strengths and firing shrinkage within accepted limits. Modulus of rupture and compressive strength values were slightly decreased by increasing the addition of EAFS and LFS. The technological characteristics were found to be affected by both the percentage of EAFS and LFS added as well as their grain size. Finally, the leaching test performed showed stabilisation of all studied toxic elements within the sintered ceramic structure.

An application of luminiscence dating to building archaeology: The study of ceramic building materials in early medieval churches in north-western France and south-eastern England

The research reported in this thesis concerns the re-evaluation of an archaeological assumption surrounding the origin of Ceramic Building Materials (CBM) used from the 9th to the 11th century in religious buildings of north-western France and south-eastern England. Are the bricks used in the masonry structures Roman spolia or a novo productions? Amongst the dating methods that can contribute to building archaeology, it is the technique of stimulated luminescence applied to CBM that is the focus of this study. Results from thermoluminescence (TL) and optically stimulated luminescence (OSL) dating performed on 52 CBM samples from 11 churches showed that the practice of reusing Roman brick was commonplace in small parish churches, but also that brick-making was not a totally unknown skill of the early medieval craftsmen as it has long been supposed. Most importantly, by identifying that the building material is contemporary to the church, a defined chronology emerges resulting in a new and extremely useful reference point in the history of early medieval architecture.

Evolution with Temperature of Crystalline and Amorphous Phases in Porcelain Stoneware

Porcelain stoneware tile is a ceramic building material characterized by high technological properties, especially regarding water absorption, chemical and frost resistance, bending strength and abrasion resistance. Because mineralogy is one of the main factors affecting the mechanical properties of porcelain stoneware, a complete determination and quantification of the mineral and amorphous phases is of special importance in the study of porcelain stoneware tiles. In the present work, a reference industrial composition (50% kaolinitic clay, 40% feldspar, and 10% quartz) of porcelain stoneware tiles fired at different temperatures (400°–1400°C) was characterized by X‐ray powder diffraction combined with quantitative full‐phase analysis using the Rietveld method, including amorphous content. The green composition contained albite, microcline, and muscovite as fluxing agents, which start to decompose at low temperatures (400°–800°C range) and are completely dissolved above 1200°C. The mullite phase is formed from 1100° to 1230°C and at the latter temperature, quartz particles start to dissolve. Studies of mineralogical evolution have revealed that the high heating rate (45°–50°C/min) required in ceramic tile manufacture leads to significant differences in comparisons with whiteware ceramics fired at a lower heating rate (10°C/min). Thus, the formation of mullite in porcelain stoneware occurs at higher temperatures (1100°C) whereas the transformation of β‐quartz to β‐cristobalite does not take place. The experimental results of this study show that qualitative mineralogical analysis, based on the intensity of a particular diffraction peak for each crystalline phase, is a suitable methodology to obtain preliminary knowledge of mineralogical changes with temperature.

Effect of firing temperature on sintering of porcelain stoneware tiles

Porcelain stoneware tile is a non-equilibrium porcelain material produced by a fast firing process of kaolinitic clay, quartz and feldspar mixtures. This building material, generally used in pavements and also as wall covering and ventilated façades, is endowed with high technological properties such as low water absorption, high bending strength and abrasion resistance, and excellent chemical and frost resistance. These properties cause that porcelain stoneware tile was actually the material with the highest increase in production and sales over all other ceramic building material. Nevertheless, there is a scarcity of high quality research focused on the effect of mullite growth on technological properties of porcelain stoneware tile and on the effect of different fluxing agents on both mullite growth and evolution of physical and technological properties during firing. In this paper, the behaviour of a potassic porcelain stoneware body during the firing process is investigated. A porcelain stoneware composition was prepared by mixing 50% kaolinitic clay, 40% feldspar and 10% quartz. The samples were sintered following a fast firing process. The sintering behaviour of the fired samples was evaluated by linear shrinkage, water absorption and porosity measurements. Both green powder and fired samples were characterized by means of differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), dilatometry and bending strength measurements.

Efflorescence and its quantification in ceramic building materials

AbstractA study of the effect of cement in the formation of efflorescence on the surface of ceramic building materials was conducted. Wicking tests were performed with bricks covered with cement, and a test procedure, where temperature and water pressure applied to the samples could be controlled, has been developed. Salts formed at brick surfaces consist of arcanite (K2 SO4 ). Results show that salt deposition kinetics are enhanced by higher test temperature and particularly by imposing water pressure around the brick. A method to quantify efflorescence was developed in order to avoid any subjectivity in the assessment of the test results. Image analysis offers an alternative for quantification of this phenomenon. Study of efflorescence digital images lead to the definition of an efflorescence coefficient. A set of samples with low to high levels of efflorescence was used and the results show a clear distinction between different degrees of efflorescence. It is concluded that this process is a valid one ...

Utilization of Technogenic Products in Production of Ceramic Building Materials

The possibility is studied and substantiated of using coal mining waste, metallurgical slag, oil shale processing products, and household waste in the production of ceramic construction materials. Practical recommendations are issued.

The Production of Ceramic Materials in Roman Pavia: An Archaeometric NAA Investigation of Clay Sources and Archaeological Artifacts

Part of a research program on cultural heritage aimed to elucidate the production of ceramic artifacts in Roman Pavia is devoted to the localization of the possible sources of raw materials (claypits) as well as to the technological production processes. Clay samples were collected in two different areas nearby Pavia, Lomellina and Oltrepo. Some of these samples were also fired at 950 °C. Archaeological ceramic samples, mostly bricks and tiles of Roman age, were obtained from excavations of Roman settlings close to Pavia. All samples were submitted to instrumental neutron activation analysis for the determination of Ca, Fe and a number of trace elements. Results indicate (1) fired and raw clay samples keep the same elemental fingerprint so that only raw samples data can be used in archaeometric studies; (2) some parameters based on rare earth elements are useful to discriminate the clay samples from the two investigated areas; (3) clay discrimination is confirmed also by discriminant analysis; and (4) the insertion of the elemental composition data of the ceramic artifacts in the statistical treatment allows one to assign the artifacts to one of the investigated areas and confirms that, at Roman times, the production of ceramic building materials was mostly based on the use of local prime matter.

97/04096 Production of ceramic building materials in Russia from anthracite tailings

97/04096 Production of ceramic building materials in Russia from anthracite tailings

Ceramic Building Materials: An Alternative in Disposal of Sewage Sludge

The increased sewage sludge production from domestic wastewater treatment plants, has become a serious environmental problem. In Portugal the principal way of disposal, is on agricultural land, however this way is unsuitable, not only because land is limited, but also because there are strict regulations in terms of location, categorised site, gas emission, leachate escape, etc. The high organic content of sewage sludge makes it a waste with a considerable calorific value; the inorganic content usually 10 to 30 % is mainly silt and clay minerals. This paper presents results regarding the use of sewage sludge and pore agent additives (mainly forest waste). The development of heavy clay materials as an alternative solution for sludge disposals. Addition of sewage sludge prove to be a way of waste recycling and energy saving The benefits and difficulties to both brick manufacturer and environmental protection are pointed-out. Physical, chemical and mineralogical composition of sewage sludge, forest waste and clay are studied. The influence of such additives on the brick final properties such as mechanical strength, shrinkage, specific gravity and water absorption are presented. Special focus was given to the environmental risk which might ensue from the utilisation of the new material by performing among others, leaching tests, in order to measured the leachability of inorganic substances from the ceramic matrixes. The leaching tests performed were single and sequential batch tests and, in general, they suggest that municipal sewage sludge within the typical heavy metal content could be incorporated within the brickmaking process with absent on negligible leaching potential.

Moisture Expansion in Ceramic Building Materials

Moisture Expansion in Ceramic Building Materials

The Scientific Investigation of Bricks from St. Urban (13th Century Cistercian Monastery, Lucerne, Switzerland)

The bricks at St Urban have been the focus of scientific enquiry for rather less than a decade. In 1995 excavations revealed new bricks of extraordinary quality, design and size. The majority of these red coloured bricks are up to 45 centimeters in length, 34 centimeters in depth and 11 centimetres in height, making them extremely unusual as building materials. Similar bricks have been found in other places in Switzerland (Aarau, Basel, Fraubrunnen, Zofingen) and are generally considered to be imports from the St. Urban brick manufactory. The present research is concerned firstly with the chemical and mineralogical composition of the bricks and the establishment of a new reference group. The research also aims at the technical aspects of the manufacture (especially the firing) of these extremely large bricks. The bricks were sampled using a core drill or simple hammer and chisel. In this way we obtained profiles through the brick from rim to core. So far 76 samples including 10 samples of raw materials have been analysed. The mineralogical composition of the bricks analysed by x-ray powder diffraction is quartz, potassium feldspar, plagioclase, hematite. White mica and calcite are sometimes present. The approximate maximum firing temperatures were from 900 to 950 °C. The ambient atmosphere during the firing of the bricks was oxidising, even if partially reducing conditions were observed (black cores). To examine the chemical homogeneity of the ceramic building materials major and trace element analyses were carried out using x-ray fluorescence. This was also performed in order to identify similar ceramics with a different provenance. The results of 46 samples from St. Urban show a relativley homogeneous chemical composition. As well for the 16 samples from Aarau, Basel, Fraubrunnen and Zofingen there is -until now- no evidence which points to a production center other than St. Urban. Raw materials (red clays, coloured marls and sands of the Aquitanian molasse) from an outcrop near St. Urban have been sampled and analysed. The red calcium-poor (less than 1 wt%) clays are composed of illite, chlorite and montmorillonite. The coloured marls additionally contain calcite. The sands (quartz, potassium feldspar, plagioclase, calcite, white mica, chlorite, biotite) are poor in carbonate, but only in the upper levels of the outcrop. The chemical and mineralogical composition of the sands was compared to those of the bricks from St. Urban. For the majority of the bricks a correspondance was found with mixtures of clays and sands, which were used as tempering materials. Thin sections of older and recent brick samples were made in order to compare the textures, grain size distribution and quantity of the tempering material. In addition, experiments on several clay mixtures close to the average brick compositions were carried out to investigate their drying sensitivity and firing behaviour. As it seems difficult to compare firing conditions in small electric kilns with production in the thirteenth century, a kiln has been built to imitate medieval brick making and firing. Firing experiments using this kiln are scheduled for September 1997.

Four excavations in Perth, 1979-84

Reports: medieval--post-medieval malting kilns at `Mill Street' by Martin Brann & Neil McGavin (ed David Bowler) (918--30); early medieval buildings at `King Edward Street' by Peter Clark & Linda Blanchard (ed David Bowler) (931--8); investigations into possible Dominican Friary site at `Kinnoull Street' by David Bowler & Derek Hall (939--47) including cemetery evidence; `Blackfriars House' by David Bowler & Derek Hall (947--54). The artefacts section, by B Ford (959--79) includes notes on: `Horse equipment' by B Ellis (963); `Numismatica' by N Holmes (965); `Porous ceramic material' by C Underwood (965); `Stone shot' by M Brann (966); `Doorway pediment' by N Cameron & D Bowler (966); `Ceramic building material' by D W Hall (968, 970); `Textiles' by H Bennett (971); `Leather' by C Thomas & A Walsh~(971). There are details of `The human skeletal remains from Kinnoull Street' by M Bruce (ed A Cox) (979--85), `Animal bone' by C Smith (986--9), `The botanical remains: Mill Street & King Edward Street' by D Robinson (ed C Smith) (990--3). Finally, `Pollen and particle size analysis of ditch deposits' by D Robinson (ed C Smith) (994) concludes proceedings.

95/06443 The use of lignite ash in the production of ceramic building materials

95/06443 The use of lignite ash in the production of ceramic building materials

Accident dosimetry using porcelain: TL analysis of low dose samples

Some of the bricks and tiles collected on previous occasions from the region of Chernobyl were found to be contaminated. In addition, in some regions there was a lack of quartz-bearing ceramic building materials. Porcelain fittings, however, are plentiful, both inside and outside dwellings and give a sensitive thermoluminescent signal when using the pre-dose technique. Four types of porcelain domestic fittings, with accumulated doses of less than 200 mGy, were collected from an apartment block in Pripyat which is being modelled and for which accurate TL measurements are required for comparison. The work has concentrated on establishing criteria for the selection of the samples with the best TL properties and on improving the precision of the pre-dose additive dose method for dose evaluation. Important factors for selection of samples in this dose range (<200 mGy) are the ratio S 0/ S n and the sensitivity. The image intensifier proved to be a useful tool for examining the spatial distribution of TL over the porcelain surface and identified one high S 0 sample where the signals from the unactivated and activated sample were emitted from different regions of the surface.

Frost Damage of Ceramic Building Materials

Frost Damage of Ceramic Building Materials

Ceramic Building Materials

Ceramic Building Materials

Conference of the Ukrainian producers of ceramic building materials

Conference of the Ukrainian producers of ceramic building materials

New developments in the production of ceramic building materials

New developments in the production of ceramic building materials

Seminar of Laboratory and Inspection Department Chiefs of Ceramic Building Materials Plants

Seminar of Laboratory and Inspection Department Chiefs of Ceramic Building Materials Plants