Fired Clay Bricks Research Articles

Physical and Mechanical Properties of Fired Clay Brick Incorporating with Mosaic Sludge Waste

Brick is one of the most common masonry units used as building material. Due to the demand, different types of waste have been investigated to be incorporated into the bricks. Many types of sludge have been incorporated in fired clay brick for example marble sludge, stone sludge, water sludge, sewage sludge, and ceramic sludge. The utilisation of these waste materials in fired clay bricks usually has positive effects on the properties such as lightweight bricks with improved shrinkage, porosity, and strength. Therefore, this study focus on the incorporation of mosaic sludge into fired clay brick. Physical and mechanical properties were conducted such as compressive strength, shrinkage, density and initial rate of suction test. From the results, it shows that brick with 5% of mosaic sludge obtained the best result with highest compressive strength and low initial rate of suction (18.76N/mm2 and 10.08 g/mm2) respectively. Nevertheless, all the other properties for all bricks incorporated with different percentages of mosaic sludge were complied with the standard. In conclusion, mosaic sludge could be an alternative low cost material for brick and at the same time provide a disposal method for mosaic sludge waste.

Testing on Building Material Using Waste Material in Fired Clay Brick

Clay brick is one of the building materials that have been used in the construction field for thousand years. It has been used as a major construction material because it can tolerate with severe weathering action, flexible properties and it is easy to handle. Many researchers have been incorporated waste material such as organic waste, waste treatment sludge, fly ash, cigarette butts, rice husk and processed waste tea into fired clay brick. This application gives an idea to use waste material that will give a minimum impact to the real environment. In this study, high calorific value waste such as cigarette butts (CBs) were incorporated into fired clay brick. Different percentages of CBs (0%, 2.5% and 5.0%) were added into the raw clay brick. All samples were fired up to 1050°C with different heating rates (1°C/min, 3°C/min and 5°C/min). Properties including compressive strength, dry density, firing shrinkage and water absorption are reported and discussed. The results show that the compressive strength of fired clay brick was obtained with 2.5% CBs of fired clay brick at 1°C/min heating rate compared to others. As for the density, it was reduced with higher percentages of CBs incorporated into the raw clays. From the results, water absorption was slightly increased when CBs were incorporated into clay brick. The results suggested that heating rates at 1oC/min is adequate to achieve optimum properties.

Leachability of Fired Clay Brick Incorporating with Sludge Waste from Mosaic Industry

The amount of sludge wastes from industrial, mining, domestic agriculture activities are about 60200 tons per year. The increasing of the waste will have significant impact towards environment and energy conservation. Many attempts have been made to incorporate sludge waste into brick for example fly ash sludge, sewage sludge, water sludge and ceramic sludge and advantages on the properties have been found but heavy metals leachibility will be the main concerned. Therefore, sludge waste is a potential alternative to convert into useful products as a building material that can alleviate the disposal problems. Therefore, in this study, the characteristics of heavy metals were determined by using XRF. Four different mixing ratios of mosaic sludge waste at (0%, 1%, 5%, and 10%) were incorporated into fired clay brick. Each brick was fired in a heat controlled furnace at elevated temperatures of 1050°C. The characteristic of heavy metals from the sludge waste were determined by XRF and the result show that the sludge waste is high in iron (Fe) and Zicronium (Zr) followed by Barium (Br), Chromium (Cr), Cadmium (Cd), Copper (Cu) and Zinc (Zn). The leachability of heavy metals from the manufactured mosaic sludge brick were determined by using toxicity characteristic leachibility procedure (TCLP) and the results demonstrated that the culprit heavy metals were all complied to USEPA(1996) and EPAV(2005a).

An Overview of Sludge Utilization into Fired Clay Brick

An Overview of Sludge Utilization into Fired Clay Brick

Development of better insulation bricks by adding mushroom compost wastes

This paper studies the application of spent mushrooms compost (SMC), as a new additive to produce bricks with better insulation and in a more sustainable way. The aim is to determine how SMC adding varies properties of fired clay bricks (FCBs), specially the thermal behavior, and whether it is a viable solution for recycling SMC. Clay was mixed with different percentages of SMC (0–17 wt.%) and formed by pressing. Samples were fired at the facilities of the partner's factory up to 950 °C. The influence of SMC on FCBs was related to its thermal conductivity (TC), compressive strength (CS), water absorption (WA), bulk density (BD), linear shrinkage (LS), apparent porosity (AP) and weight losses during firing (WL). As a result, a blend of clay with up to 17% SMC, limited by minimal CS and WA, may be used for masonry works with an enhancement on thermal behavior. Addition of 17% of SMC leads to a 26.17% decreasing in TC compare to those without SMC, achieving a minimum TC of 0.55 W/m K. This implies a reduction of 10% on the equivalent thermal transmittance, that means a better insulation of the buildings and thus this is an important energy saving.

Effect coal ash on some refractory properties of alumino-silicate (Kankara) clay for furnace lining

The work aimed on the improving the refractory properties of Kankara clay (alumino-silicate) found in Kankara Village, Katsina State, Nigeria by blending with coal ash for the production of refractory bricks was investigated. Coal ash additions were varied from 5 to 25 wt% in the blend. Refractory properties such as: linear shrinkage, apparent porosity, bulk density, cold crushing strength and thermal shock resistance were tested. The results were compared with standard refractory properties for fireclay bricks. All the values obtained from the blends are within the recommended values for medium fireclay bricks. Hence, addition of coal ash to Kankara clay enhanced the refractory properties; the bricks were used in the production of heat treatment furnace with good thermal resistance.

Valorization of Mill Scale Waste by its Incorporation in Fired Clay Bricks

The mill scale (MS) waste is produced in steel industry during the milling process from the rapid oxidization of the hot iron products, and is mainly consisted of iron oxides (>95%). The aim of this work is to evaluate the utilization of MS (known in Greece as “kalamina”) as an admixture in clay bricks manufacturing by applying extrusion and sintering processes. For that purpose, specimens were formed from various clay/MS mixtures (up to 9 wt% MS) and then fired at different temperatures (up to 1100°C). Shrinkage and weight loss upon firing as well as density, porosity, bending strength and thermal conductivity of sintered specimens were determined and studied as a function of the % MS content and the firing temperature for optimization. The experimental results show that the incorporation of MS in clay bricks production is feasible, as an efficient secondary resource, thus turning waste from one industry into useful feedstock for another one. Specifically, the mechanical performance and thermal conductivity are not significantly affected with increasing the mineral admixture percentage and the sintering temperature.

Paradoxical drying of a fired-clay brick due to salt crystallization

We investigated how salt crystallization inside a porous building material influences the formation of a receding drying front. Nuclear Magnetic Resonance (NMR) is used to measure non-destructively both hydrogen and dissolved sodium ions during drying process. In this study, we focused on the influence of NaCl on the drying behavior of porous media. The results show that salt changes the drying behavior. At low relative humidities (RH~0%), the drying rate of a brick saturated with NaCl solution is much lower than the drying rate of water saturated brick. Moreover, the presence of salt suppresses the development of a receding front. In this case homogenous drying of the material continues till very low saturation values. This is due to salt crystallization near the surface of the brick that causes blockage of the pores. This blockage reduces evaporation rate at the surface and allows maintaining a continuous hydraulic connection between the surface of the porous medium and the liquid present inside the material till low saturation values. In the case of a salt solution saturated brick, increasing relative humidity to 55% and 70% leads to a paradoxical situation where the evaporation rate is greater for 55% and 70% RH than for 0% RH. The paradox is explained by the impact of evaporation rate on the efflorescence microstructure, leading to the formation of a blocking crust for sufficiently high evaporation rates and non-blocking efflorescence for sufficiently low evaporation rates. The fundamental difference between the two types of efflorescence is demonstrated from a simple imbibition experiment. Using a simple continuum scale model of drying, critical moisture content was determined and all the essential features of the experimental results are validated. It is shown that critical moisture content can be very low in the case of fired-clay brick due to the low threshold of the pore space, which is consistent with the relatively large pore size distribution of the fired-clay brick.

Effect of osmotic pressure on salt extraction by a poultice

Salts are widely recognized as a cause of deterioration of porous building materials. A general approach to slow down salt damage problems is reducing the salt content of the affected object. One of the most common treatments is the application of poultices. Desalination by poultices may result from two different salt transport processes: diffusion and advection. In this study we consider only the advection process. In the case of advection based desalination the efficiency of salt extraction strongly depends on the pore-size range of the substrate and the poultice. For advection to be effective, the poultice materials should be adapted to the pore-size distribution of the substrate. However, the poultice can shrink during drying, which affects the pore-size distribution of the poultice material. The salt transport from the poultice to the substrate by water advection results from a capillary pressure gradient, but upon drying a salt concentration gradient may appear in the poultice/substrate interface. Because of this concentration gradient an osmotic pressure arises, which may change the drying behavior of the poultice/substrate system. We have investigated the effect of the pore size distribution of the poultice and the osmotic pressure on the drying behavior of a poultice/substrate system. To this end, we have measured the time evolution of moisture and salt concentration profiles in a system consisting of kaolin/sand poultice on a fired-clay brick, using a specialized NMR setup. Comparison of the results with a model based on capillary pressure equilibrium at the poultice/substrate interface shows that the accumulation of salt from the substrate in the poultice may improve the salt extraction process, because the osmotic pressure decreases the effective pore size of the poultice.

Porosity–density relations in stone and brick materials

The open porosity of a specimen of stone or brick material is often measured using a gravimetric method based on Archimedes’ principle. This widely used technique also allows both the bulk density and the solid density of the specimen to be determined, although the solid density is not often reported. We discuss the relation between the porosity and density, both for single specimens and for groups of specimens of similar materials, using for illustration data on limestones, sandstones and fired-clay bricks. The significance of the solid density can be overlooked but it is informative both as a material property and as a method of identifying errors in data. We emphasize how the solid density depends on mineralogy and on closed porosity.

Experimental and Theoretical Analysis on Thermal Conductivity of Fired Clay Bricks Incorporated with Cigarette Butts

Currently higher requirements in thermal performance is needed for the quality of building materials especially fired clay bricks. Thermal conductivity is an important criterion as it will influences the heat losses from building. The objective of this study is to validate the estimation value of thermal conductivity by using theoretical value with the experimental work conducted in the laboratory. The experiment data was collected in order to compare with a theoretical model that obtained the thermal conductivity value based on it relationship with dry density of fired clay bricks. Different percentages of CBs (0%, 2.5% and 5.0%) were incorporated into fired clay bricks. Different heating rates were applied during firing stage, which are 1°C/min, 3°C/min and 5°C/min respectively. All samples were fired up to 1050°C. The experimental work for thermal conductivity was carried out using the Hot Guarded Plate Method. Meanwhile, the theoretical result was obtained from the previous study using model developed. Throughout statistical analysis, some trend of thermal conductivity and dry density were revealed. The analysis results show that as the dry density decreased, thermal conductivity also decreased.

Gamma spectrometric characterization of refractory products used in Turkey

This is the first detailed study related to the radiometric characterization of refractory materials produced for use in the industries of iron–steel, cement and glass manufacturing in Turkey. In this study, the activity concentrations of 226Ra, 232Th and 40K naturally occurring in 52 refractory material samples collected from Turkey's leading refractory factories were measured by using a gamma spectrometer with HPGe detector. Results show that the natural radioactivity of refractory material samples varies depending on raw material. The values of the activity concentrations of 226Ra, 232Th and 40K measured in the refractory brick and concrete samples varied from 1.3 to 384.2Bqkg−1 (average: 173.5±20.2Bqkg−1), 2.9 to 392.9Bqkg−1 (average: 176.7±20.8Bqkg−1) and 18.9 to 679.6Bqkg−1 (average: 130.4±23.9Bqkg−1) and 24.0 to 158.2Bqkg−1 (average: 73.3±10.5Bqkg−1), 25.0 to 134.4Bqkg−1 (average: 76.3±10.8Bqkg−1) and 31.0 to 480.0Bqkg−1 (average: 172.8±40.5Bqkg−1), respectively. The activity concentrations of 226Ra and 232Th measured in fireclay brick and high alumina brick samples are significantly higher than the average values of earth's crust.

Behavior of hollow clay brick masonry walls during fire. Part 2: 3D finite element modeling and spalling assessment

In the first part of this work [1], the fire behavior of masonry walls made with hollow fired-clay bricks was investigated experimentally. Several complex mechanisms occurred during firing are analyzed and identified. In particular, in cases of load-bearing walls, the local spalling of bricks is considered as an important factor governing the fire performance of masonry walls.In this second part, fired-clay masonry is investigated by theoretical approach with the finite element method in order to predict its behavior and its performance under fire exposure. For this purpose, a 3D numerical simulation is conducted with paying a particular attention to the spalling risks of alveolus bricks.

Physical and Mechanical Properties of Fired Clay Bricks Incorporated with Cigarette Butts: Comparison between Slow and Fast Heating Rates

In general, firing process in brick manufacturing could affect the properties, colours and appearance of the brick. The main purpose of this study was to evaluate the effect of different heating rates on physical and mechanical properties during the firing of standard bricks and bricks incorporated with cigarette butt (CB). In this investigation, two different heating rates were used: slow heating rate (2oC min-1) and fast heating rate (5oC min-1). Samples were fired in solid forms from room temperature to 1050oC. All bricks were tested for their physical and mechanical properties including compressive strength, initial rate of absorption and density. Higher heating rates decrease compressive strength value but slightly increase the initial rate of absorption and density properties respectively. In conclusion, higher heating rates are able to produce adequate physical and mechanical properties especially for CB Brick.

Applicable Fine Stream Sediments from Upper Chi River Produced Fired Clay Bricks

Stream sediments from the upper Chi River basin, including Chi and Nam Phong sub-watershed, are applicable to be a source of raw materials to produce fired clay bricks. The sampling locations of clay materials are generally found along the river terrace where are covering three different regions (upper-, mid-and lower sub-watershed) nearby brickyards. Quartz is the main mineral of all samples. Moreover, mainly clay mineral groups consist of mica, kaolinite, and chlorite group composing totally around 5%. Other mineral compositions, such as carbonate, evaporite, corundum, hematite and pyrolusite are normally found both in fine stream sediments and fired clay bricks. Additional minerals in fired bricks are forsterite, zircon and mullite group which are less than 0.2%. Their strength in submersion test expressed in the air-dried to pure water both 1 day and 5 days is revealed that their strength and strain intend to increase with the submersed brick. Besides, prism compressive strength decreases in half related to a fired brick unit. Their impact resistances are significantly distinctive by mineral composition of clay mineral group and silica. The compressive strength of air-dried fired brick at the ultimate stress and strain corresponding by time in water absorption test show that water filled in void or pore can enhance their strength and strain. Thus, fired clay bricks are capable to resist compressive force than the normal condition.

Influence of Rice Husk Ash on the Engineering Properties of Fired-Clay Brick

The aim of this study is to determine the influence of rice husk ash (RHA) on the engineering properties of fired-clay brick with the present of 10% sand. Temperature 1200°C is selected as the optimum temperature based on the preliminaries study. X-ray Diffraction (XRD) and X-Ray Fluorescence (XRF), were carried out to determine the characteristic of raw materials used. Mechanical properties of rice husk ash-clay bricks are determined in terms of compressive strength, porosity and water absorption. The results shows that increase in RHA replacement percentage reduce the compressive strength and linear shrinkage of fired-clay bricks while the porosity and water absorption value increase. From the investigation, we can conclude that the optimum mixing ratio for fired-clay brick containing RHA is 15% because it complied with the minimum requirement for building material in term of strength and water absorption.

Unusual water transport properties of some traditional Scottish shale bricks

Sorptivity, porosity and pore size distribution have been measured for five types of pressed fired-clay bricks recovered from a Second World War airfield in East Lothian, Scotland. It was found that the bricks, all manufactured locally from colliery shale, had similar porosities but significantly different compositions, leading to differences in pore structure and transport properties. Unusually high concentrations of organic carbon were found by analysis. In imbibition tests using water and n-decane, capillary absorption generally did not scale with time1/2, indicating material non-uniformity in the flow direction. A sharp front n-layer model was used to estimate the variation of sorptivity and permeability in drilled cores taken through bed and stretcher faces. A surface skin of lower sorptivity was found in some materials. This is attributed to compression of the green clay in the brick mould during manufacture. Comparison of water and decane imbibition showed that water sorptivity is reduced throughout by partial wettability. This hydrophobicity of these shale bricks is tentatively related to their high organic carbon content, which is incompletely burned out during firing. We show how the partial wettability may be expressed in terms of a wetting index derived from imbibition data.

Use of TEOS for fired-clay bricks consolidation

Ethyl silicate (tetraethylorthosilicate, TEOS) is one of the most used consolidants for natural stones in the restoration of architectural and cultural heritage and the literature concerning its performance in this application is quite abundant. In this paper, the need, and sometimes urgency, of preserving ancient fired-clay elements (bricks and terracotta decorations) is highlighted as well, and the effects of ethyl silicate consolidation (75 wt% TEOS in white spirit) are investigated from a microstructural, physical-mechanical and aesthetic point of view. Fired-clay brick samples (open porosity &45 %; compressive strength &14 N/mm 2 ) were treated and then characterized by mercury intrusion porosimetry, scanning electron microscopy, water absorption, com- pressive strength test and spectrophotometry, to assess the effects of the treatment. The TEOS treatment gave encouraging results: a good penetration depth (about 10 mm), a limited reduction in porosity, a large decrease in water absorption, a significant improve- ment in compressive strength and a positive aesthetic outcome. The results obtained pointed out TEOS treatment as a promising solution for fired-clay bricks consolidation.

Efficient Lining for Steel-Pouring Ladles

An analysis was made of the reasons for the short service life of the lining of steel-pouring ladles and malfunc- tions of fountains used for bottom-pouring. A high-temperature adhesive was developed and the most chemi- cally stable refractory materials were chosen for it. The operating regime of steel-pouring ladles in the open-hearth shop at the Revda Hardware-Metallurgical Plant (in Revda) was studied, and based on the study results the shop replaced its fireclay bricks with MKRAP refractories. The authors used those results to also develop a mortar that has increased the life of the lining 30 - 50%. Use of the highly stable high-temperature adhesive in fountains has reduced metal loss during bottom-pouring operations. A project was undertaken in the open-hearth shop at Revda Hardware-Metallurgical Plant (in Revda) to lengthen the service life of its steel-pouring ladles. The lining of the walls and bottom of the 22.98-m 3 ladles at the plant are made up of three-four layers of refractory bricks. The refractory materials are fireclay bricks of grades ShB-9 and ShKu-32/16, fireclay mortars MSh28 and MSh31, refractory clay, and chromium-bearing concrete. The service tempera- ture of the working layer of the lining is 1600 - 1650°C, slag basicity CaO/SiO2 is 1.5 - 2.2, and the FeO content of the slag ranges from 10 to 25%. The lining is rapidly dried and heated over a 1-2h period during the beginning of use of the ladle. The horizontal joints of the walls are coated with a fireclay mortar on a sodium-silicate binder. There are no ver- tical joints in the linings of the walls. Study of wear of the lining of ladles after service showed that the wear takes place due to spalling of the bricks as a re- sult of thermal shocks which occur during the entry and dis- charge of molten metal and the heating that the lining under- goes after a repair. The refractory of the lining also reacts chemically with reactants in the melt, particularly in the re- gion of the vertical joints. There, reactants in the slag pene- trate the lining to depths of up to 50 mm. In addition, the working layer undergoes abrasive wear in the bottom of the ladle when incoming molten metal strikes the lining. The large amount of wear of the lining in the slag zone is due to oscillation of the melt during use of the ladle. In our opinion, a lining such as that described above has several shortcomings. The presence of three-four layers in the lining creates too many joints. Also, the use of short (230 mm) bricks in such linings creates 3-4m m oftaper in the working layer, which makes it more likely that some bricks will fall out of the layer during operation of the fur- nace. Another problem is the use of a fireclay mortar on a so- dium-silicate binder, which has poor physico-mechanical properties that do not meet the requirements for the given metallurgical conversion. The fireclay bricks operate at the limit of their physico-mechanical properties during use of the ladle. The vertical joints are not coated with the fireclay mor- tar during repairs to the lining, which allows reactants in the slag and metal to penetrate the joints and thus cause greater corrosive wear. Such penetration also creates thermal stresses in the lining during each introduction and discharge of molten metal due to the large coefficient of linear expan- sion of the metal and slag compared to the refractory prod- ucts. In addition, not enough time ( 1-3h ) isprovided for drying and heating the lining after the repair and use of a la- dle. The use of water to cool the lining after metal is cast pro- duces severe thermal shocks that crack the working layer af- ter 4 - 5 castings, i.e. after 2 - 3 heats. Such cracking occurs because, in accordance with their specifications, fireclay refractories need to undergo 3 - 4 water-cooling cycles (1300°C - water) and 20 - 25 air-cooling cycles (1200°C - air at 20°C) to perform properly. Cooling of a hot lining with water can cause accidents with ladles as a result of local dis- integration of the lining during service.

Thermal Conductivity of Fired Clay Bricks Incorporated with Cigarette Butts

Billions of cigarette butts (CBs) were discarded by smokers directly into the environment. It is known that CBs are one of the environmental pollution that could caused contamination on the street, sidewalks, waterways, beaches and public areas. Due to its small size but large in volume, CBs cannot be collected easily and most of it will be disposed directly to the landfill. Moreover, there is no easy mechanism to ensure the separation of the chemicals trap inside the CBs which is toxic to the environment. Therefore, by incorporating CBs into brick bodies will be an alternative solution to CBs littering and pollution problems. In this study, different percentages of CBs (0%, 2.5% and 5.0%) were incorporated into fired clay brick. Different heating rates were applied during firing stage which are 1oC/min, 3oC/min and 5oC/min respectively. All samples were fired at 1050oC. Thermal conductivity for cigarette butt brick (CB Brick) were tested using Hot Guarded Plate Method. From the results obtained, it could be concluded that; with higher percentages of CBs, the thermal conductivity properties were also improved which is desired but most of the brick manufacturers. CBs incorporated could be an alternative pore formers to improve the thermal properties of fired clay brick. At the same time, the porosity is also increased thus the density was significantly reduced to become lightweight brick.