Thermal Conductivity Of Bricks Research Articles

The Analysis effectiveness of heat rate in 1000℃ furnace by considering the dimensions of walls melting container

The metal smelting business is expanding, moving from combustion-based to electric-powered smelts. By adjusting the quantity of electrical power that enters the heater to be transformed into heat, the temperature of the melting chamber can quickly approach 1000°C. But if the thermal resistance is unable to slow down the rate of heat transfer from the smelting chamber to the outside, the temperature inside the smelting chamber can likewise fall quickly. If that keeps happening, the furnace machine's temperature of 1000°C cannot be reached, which makes the smelting process less than ideal. So that the temperature of the smelting chamber can be maximized, an examination of the thermal resistance factor is required in order to estimate the value of the thermal resistance on the wall. To obtain information on wall dimension fluctuation, the procedure involves gathering data from references and actual measurements of the furnace. Based on the findings, it was determined that the temperature of the environment had an impact on the heat resistance values measured. (T2 = 25.8°C), the melting chamber's temperature (T1 = 1000°C), the fire brick's thermal conductivity at k=4.78 J/s m° C, as well as the variation area and wall thickness the resultant resistance increases with increasing wall thickness. The highest resistance rating is 4.389R with a 150 mm wall thickness. Otherwise, the resistance is higher when a smaller portion of the wall is employed. On a 3600 mm2 wall area, the resistance value with the highest value is 2.905R. In order to increase the temperature of the smelting chamber, a furnace with wall dimensions that have a significant thickness value and a compact area can generate the best thermal resistance

Cement and Clay Bricks Reinforced with Coconut Fiber and Fiber Dust

For generations, Sri Lankans use cement bricks and clay bricks as common building materials in the construction field. This study investigates the feasibility of improving the strength while lowering the mass and thermal conductivity of bricks by adding coconut fiber or coconut fiber dust as a reinforcing material. Each reinforcing material is used in both clay and cement bricks. The mixtures are prepared according to varying volume ratios of the raw materials used. Coconut fibers are combed and cut into 4-5 cm pieces and dry coconut fiber dust is sieved using a 4 mm sieving mesh. The mixture is prepared by hand mixing and the traditional processes are replicated in making the bricks. Tests are carried out to understand the variation of mass, compressive strength, thermal conductivity, and water absorption of the reinforced bricks in comparison to bricks with no reinforced material. The cement brick reinforced with coconut fiber achieves the expected results in the compressive strength test and thermal conductivity test but underperformed when comparing masses and water absorption. Clay bricks reinforced with coconut fiber dust show impressive results in compressive tests and with the addition of dust, the appearance seems to have changed. It is observed that reinforcing cement bricks with coconut fiber could double the compressive strength along with a 5% reduction in mass. Reinforcing clay bricks with coconut fiber dust increases its compressive strength by over 70% while decreasing the mass by over 30 %. The study proves that it is feasible to use reinforced coconut fiber or coconut fiber dust to improve the properties of both clay and cement bricks, while clay bricks reinforced with coconut fiber are an exception.

The Advantages and Disadvantages of Palm Oil Empty Fruit Bunch on Bricks and Mortar

Palm oil has a great commercial value in the global vegetable oil market, due to having several beneficial uniqueness such as significant profits and high yields for farmers, as well as effective and efficient land use. As the second-largest producer of palm oil in the world, Malaysia produces an enormous amount of empty fruit bunch (EFB) as biomass waste, whose proper and improper disposal incurs costs and environmental problems, respectively. This EFB fibre is also used to produce bricks and mortar for building construction, due to being a sustainable solution to environmental problems. Therefore, this study aims to analyze the existing literature related to the application of EFB in the civil engineering field. This focused on the properties of the fibre and its effects on bricks and mortar, to gauge the challenges and prospects of EFB products in the local industry. EFB fibre is a porous voluminous cellulose structure, whose properties vary among each other due to diverse origins, species, and biological growth conditions. This is useful in reducing the weight and thermal conductivity of bricks, as well as slightly increasing their tensile and flexural strengths. However, some disadvantages were observed for the EFB bricks, with the workability and compressive strength being lower. The water absorption of this product was also higher than normal bricks. This confirmed that EFB fibre should be minimally used in bricks and mortar. As a natural fibre, concerns are often observed on inconsistent quality, poor fire resistance, and decay risk, which need to be solved before the use of bricks in the construction industry. This study recommends several patterns of improving the strength, quality, and consistency of EFB bricks, such as the alkaline treatment, which roughens the surface area of the product to enhance the fibre- atrix adhesion.

Environmentally friendly unburnt bricks using raw rice husk and bottom ash as fine aggregates: Physical and mechanical properties

In order to reduce the serious impacts of industrial and agricultural wastes on the environment, raw rice husk and bottom ash were used as fine aggregates, while fly ash was utilized as a binder material in the production of unburnt building bricks. Two group mixtures were designed with water-to-binder (W/B) ratios of 0.30 and 0.35. The rice husk was used to replace 0%, 3%, 6%, and 9% of bottom ash content by mass. An experimental program was carried out on the brick samples at different ages from 3-day to 28-day to determine the main physical and mechanical properties of brick, such as unit weight, compressive strength, water absorption, ultrasonic pulse velocity and thermal conductivity. The microstructure of brick material was captured using scanning electron microscope technique. The experimental results allow to identify the effects of rice husk, bottom ash content as well as W/B ratio on the properties of bricks. Brick samples produced in this study had a proper compressive strength meeting the practice requirement and were classified as Grade M3.5 and 5.0 based on TCVN 6477:2016. At the use of 9% rice husk, the unit weight and thermal conductivity of bricks were really low (1.06÷1.08 T/m3 and 0.201÷0.216 W/m.K), they are conformed to be used in temporary construction and insulation structures.
 Keywords:
 rice husk; bottom ash; fly ash; unburnt brick; ultrasonic pulse velocity; thermal conductivity.

Mechanism analysis of pore structure and crystalline phase of thermal insulation bricks with high municipal sewage sludge content

As the inevitable by-product of sewage treatment, millions of tons of municipal sewage sludge (MSS) are increasingly stockpiled every year around the globe, creating enormous pressure on the environment and society. The preparation of porous insulation bricks based on MSS is put forward to realize environment protection and waste reclamation. However, the excessive amount of MSS will lead to the deterioration of strength and durability in the bricks. In this paper, the pore structure and crystalline phase of bricks were adjusted by the introduction of the ultra-fine amorphous phase, to improve the thermal insulation performance as well as the compressive strength. The thermal conductivity of the bricks could reach the lowest value of 0.194 W/(m·K) with the compressive strength of 10.2 MPa. Under the requirement of the mechanical strength, adding 3% of borax into bricks can increase the compressive strength to 18.8 MPa. The effects of the continuous dense phase and pore structure on thermal conductivity and compressive strength of bricks were investigated in reference to Bauer and Gibson model, respectively. The results provide a development direction for the preparation of thermal insulation bricks with high content MSS and alleviating the pressure of the shortage of clay.

Performance in Thermal Conductivity of Bricks Containing Palm Oil Fuel Ash and Expanded Polystyrene Beads

Sustainable development has encouraged us to sustain the balance between the development of the country and the biodiversity conservation. Productions of lightweight bricks with thermal conductivity and density that have acceptable compressive strength are accomplished. Palm oil fuel ash (POFA) was used as partial cement replacement and an expanded polystyrene (EPS) beads was used as sand replacement to manufacture of bricks. In this study, the control sample with a Cement: POFA: Sand: EPS ratio of 1.0: 0: 3.0: 0 were produce. The cement in the sample is replace by 25% of POFA and 0%, 20%, 30%, 40%, 50% of EPS. In this study, the test conducted was a thermal conductivity test and density test of the POFA, EPS beads and brick raw material. This sample was cured under full air-dry curing conditions were applied in this experiment. The density of bricks containing 0% of EPS Beads with 25% of POFA are higher than that of brick containing 50% of EPS Beads with 25% of POFA which are 1850 kg/m3 and 1357.14 kg/m3, respectively. The higher the percentage of EPS beads, the lower the brick’s density. The thermal conductivity of bricks containing 0%, 20%, 30%, 40% and 50% EPS with 25% POFA show that brick containing 50% EPS with 25% POFA have a lower thermal conductivity with 0.09 W/m°C due to the density of the sample.

Recycle of ground granulated blast furnace slag and fly ash on eco-friendly brick production

Use of industrial by-products as waste-based materials in the building industry has recently received significant attention to develop eco-friendly building materials. This paper presents an experimental study on properties of bricks containing clay, ground granulated blast furnace slag (GGBS) and fly ash (FA) at 850, 950 and 1050 °C. Physical, mechanical, thermal tests and microstructural analyses were performed. Results show that an increase in firing temperature results in a decrease in porosity and an increase in the bulk density and compressive strength of bricks. Results also show that an increase in the FA content results in an increase in porosity and water absorption but a decrease in bulk density, compressive strength, and thermal conductivity of the bricks. GGBS content has much less significant influence on porosity, water absorption, bulk density and thermal conductivity of bricks, but an increase in GGBS content leads to a significant increase in compressive strength of bricks. Even the binary brick with 30% GGBS/10% FA exhibits nearly identical properties to the control brick. These highly promising findings suggest that replacement of clay with industrial by-products can provide eco-friendly bricks, the use of which would contribute toward reducing the environmental impact of abundant waste products and conserving non-renewable natural resources.

Prediction of the Density & Thermal Conductivity of Light Bricks on the Effect of Aluminium Elements Using Artificial Neural Network (ANN)

Indonesia with abundant limestone raw materials, lightweight brick is the most important component in building construction, so it needs a light brick product that qualifies in thermal, mechanical and acoustic properties. In this paper raised the lightweight brick domains that qualify on the properties of thermal conductivity as building wall components.The advantage of low light density brick (500-650 kg/m3), more economical, suitable for high rise building can reduce the weight of 30-40% in compared to conventional brick (clay brick). To obtain AAC type lightweight brick product that qualifies for low thermal and density properties to the effect of Aluminum (Al) additive element variation using artificial neural network (ANN). The composition of the main elements of lightweight brick O (29-45 % wt), Si (25-35% wt) and Ca (20-40 % wt). Mixing ratio of the main element of light brick (Ca, O and Si) with Aluminum additive element (Al), is done by simulation method of artificial neural network (ANN), Al additive element as a porosity regulator is formed. The simulation of thermal conductivity to the influence of main element variation: Ca (22-32 % wt), Si (12-33 % wt). Simulation of thermal conductivity to effect of additive Al variation (1-7 % wt). Simulation of thermal conductivity to density variation (500-1200 kg/m3). The simulated results of four AAC brick samples showed the thermal conductivity (0.145-0.192 W/m.K) to the influence of qualified Aluminum additives (2.10-6.75 % wt). Additive Al the higher the lower density value (higher porosity) additive Al smaller than 2.10 % wt does not meet the requirements in the simulation.Thermal conductivity of AAC light brick sample (0.184 W/m.K) the influence of the main elements that qualify Ca (20.32-30.35 % wt) and Si (26.57 % wt). Simulation of artificial neural network (ANN) of light brick shows that maximum allowable Si content of 26.57 % wt, Ca content is in the range 20.32-30.35 % wt, and the minimum content of aluminum in brick is light at 2.10 % wt. ANN tests performed to predict the thermal conductivity of light brick samples obtained results of the average AAC light brick thermal conductivity of 0.151 W/m.K. The best performance with Artificial Neural Network (ANN) characteristics has a validation MSE of 0.002252.

Influence of thermal conductivity of ceramic materials on heating rate/coking time and coke quality in cokemaking

The Iron and Steel Industry has undergone a radical change, and processes have been developed continually for the faster rate of production. The thermal characteristic of reaction depends on the thermal conductivity of coal charge by progressively developing the zone of coke. In general, higher the oven temperature, the more rapid is the initial rate of heating, plastic temperature range, plasticity and volatile evolution characteristics of the coal. The higher thermal conductivity of bricks will increase heat transfer rate and consequently, the output of the oven will increase the throughput. The heating rate is also associated with the pattern of heat supply during carbonization which influences the strength and fissuring of the coke. Results show that replacement of LC-65 castable with higher thermal conductivity castable SiC-30% reduces the coking time by 50% whereas LC-85 reduces the coking time by 20% even at same coke end temperature and coke CSR. The requirement of free space temperature of the laboratories oven is different for using different thermal conductivity of the ceramic castable to maintain same heating rate and coke end temperature during coking. Results confirmed that increasing the thermal conductivity of ceramic castable decrease in the free space temperature to maintaining the constant heating rate (∼4 °C/min) and coke end temperature (∼925 °C). The results also depict that the use of SiC-30 and LC-85 castable, the input temperature should be reduced by ∼200 °C and ∼100 °C to maintain the same heating rate and coke end temperature as compared to LC-65 castable. The study will also beneficial for reducing the Noxs.

Optimization of thermal conductivity lightweight brick type AAC (Autoclaved Aerated Concrete) effect of Si & Ca composition by using Artificial Neural Network (ANN)

Lightweight brick is the most important component of building construction, therefore it is necessary to have lightweight thermal, mechanical and aqustic thermal properties that meet the standard, in this paper which is discussed is the domain of light brick thermal conductivity properties. The advantage of lightweight brick has a low density (500-650 kg/m3), more economical, can reduce the load 30-40% compared to conventional brick (clay brick). In this research, Artificial Neural Network (ANN) is used to predict the thermal conductivity of lightweight brick type Autoclaved Aerated Concrete (AAC). Based on the training and evaluation that have been done on 10 model of ANN with number of hidden node 1 to 10, obtained that ANN with 3 hidden node have the best performance. It is known from the mean value of MSE (Mean Square Error) validation for three training times of 0.003269. This ANN was further used to predict the thermal conductivity of four light brick samples. The predicted results for each of the AAC1, AAC2, AAC3 and AAC4 light brick samples were 0.243 W/m.K, respectively; 0.29 W/m.K; 0.32 W/m.K; and 0.32 W/m.K. Furthermore, ANN is used to determine the effect of silicon composition (Si), Calcium (Ca), to light brick thermal conductivity. ANN simulation results show that the thermal conductivity increases with increasing Si composition. Si content is allowed maximum of 26.57%, while the Ca content in the range 20.32% - 30.35%.

Mechanical and thermal characterization of stabilized earth bricks

In Senegal, soil is used in construction with a misunderstanding of the thermal and mechanical properties. The lifespan of building considerably depends of the mechanical properties of construction materials used. The thermal properties of construction materials have considerable influence on the energy performance of the building. This work deals with the determination of thermal and mechanical properties of soil bricks stabilized with cement produced by five handicraft manufacturers. For the mechanical characterization, we determine the compressive strength of bricks using a mechanical press. The thermal characterization is to determine thermal capacity and thermal conductivity of bricks by asymmetrical transient Hot Plate method. The results show that vibrated bricks have a compressive strength of about 1.6 MPa and a thermal conductivity of about 0.8 W.m-1.K-1. The compressed bricks have better compression strength of about 2 MPa and a thermal conductivity of about 0.7 W.m-1.K-1.

Thermal performance enhancement of eco-friendly bricks incorporating agro-wastes

Thermal conductivity of bricks is an important parameter as it directly influences the heat losses from buildings and thus increases the energy consumption. The main focus of this study was to develop thermally efficient burnt clay bricks incorporating agricultural wastes on industrial scale. For this purpose, agricultural wastes (sugarcane bagasse ash (SBA) and rice husk ash (RHA)) were acquired from a sugar industry and a brick kiln. Burnt clay bricks were manufactured in an industrial kiln by incorporating SBA and RHA in various dosages (i.e. 5%, 10% and 15%) by clay weight. Physico-mechanical and thermal properties of brick specimens incorporating agricultural wastes were studied. It was observed that lighter weight bricks can be produced using agricultural wastes, which are helpful in reducing both the cost and overall weight of the structure. Addition of agricultural wastes in burnt clay bricks resulted into reduced compressive strength. However, brick specimens incorporating SBA and RHA up to 15% satisfied the minimum requirement for compressive strength according to different standards for masonry construction. Increase in apparent porosity with decrease in thermal conductivity was also observed with increasing content of SBA and RHA in burnt clay bricks. Substitution of clay by 15% SBA and RHA in the production of burnt clay bricks reduced the thermal conductivity by 31% and 29%, respectively. Microscopic images also showed the presence of interconnected and irregular shaped open pores after addition of agricultural wastes in burnt clay bricks. Based on this study, it can be concluded that the utilization of SBA and RHA (up to 15% by clay weight) in manufacturing of burnt clay bricks is not only helpful in landfill reduction but also leads towards the development of sustainable and thermally efficient construction material.

THERMAL CONDUCTIVITY, COMPRESSIVE STRENGTH AND WATER ABSORPTION OF RECYCLED COCONUT FIBRE AND CRUSHED CLAY BRICK MASONRY

This study aims to investigate the thermal conductivity, compressive strength and water absorption analysis of recycled masonry bricks using coconut fiber and crushed clay bricks as a partial sand replacement to create a green building material. The variable ratios of coconut fiber were considered and 10 specimens per sample were manufactured manual process using hand. Four (4) series of brick mix design from the total weight of the sand with different levels of coconut fiber and crushed clay brick replace half of the sand was created as irregular mixes comprises of 0%, 2%, 4% and 6% of coconut fiber. Overall, the use of coconut fiber and crushed clay brick as a partial sand replacement reduce the brick thermal conductivity. Thermal properties were measured based on the transient line heat source method using a KD2 Pro thermal properties analyzer. The suitable percentage of partial sand replacement for sand-cement brick using coconut fiber in this study was 4% and 50% of crushed clay brick after compared to commercial brick. The average sample of 4% coconut fiber was 0.532 W/mk of thermal conductivity and 18.74MPa compressive strength with density of 1716.28 kg/m3. In short, the thermal insulation potential of coconut fiber and crushed clay brick is highly promising for commercial development in Malaysia.

Eco-fired clay bricks made by adding spent coffee grounds: a sustainable way to improve buildings insulation

This paper shows a research for lightweight bricks development, by improving thermal properties, which has been carried out in partnership with a brick factory. The aim is to describe the thermal behavior of fired clay bricks made by spent coffee grounds in order to obtain better enclosure insulation. Organic substances combust within the matrix, during the firing process and an increased porosity is obtained. Therefore brick thermal conductivity is reduced. However, this porosity influences other parameters that determine the usability of the bricks, such as the percentage of water absorption and compressive strength, mainly. Several tests have been conducted for different percentages of waste in order to obtain bricks that meet with the regulatory requirements, settled by standards but with the minimum thermal conductivity. The results have been analyzed and related to previous researches concluding that is possible to add 17 % of waste while bricks compressive strength is above 10 N/mm2 which means they can be used for structural purposes. However bricks made by adding 17 % must be coated, therefore must not be used for facing bricks. In this case thermal conductivity is reduced up to 50 %.

Investigation of Potential Benefits of Using Bricks of High Thermal Capacity and Conductivity in a Rotating Calcining Kiln

Petroleum coke is processed into calcined coke in a rotary kiln, where the temperature profiles of flue gas and coke bed are highly nonuniform due to different flow and combustion mechanisms. Motivated by saving energy costs, the effect of refractory brick’s thermal properties on potential energy savings is investigated. This study focuses on investigating potential energy savings by replacing inner one-third of existing bricks with higher thermal capacity (Cp) and/or higher thermal-conductivity (k) bricks. This paper investigates the postulation: the bricks with higher thermal capacity could store more thermal energy during the period in contact with the hot gas and would release more heat to the cock bed when the bricks rotate to the position in contact with the coke bed. A rotational transient marching conduction numerical simulation is conducted using the commercial software FLUENT. The impact of brick heat capacity and thermal conductivity on transporting thermal energy to the coke bed is analyzed. The results show the following: (a) Increasing the heat capacity of brick layer reduces brick temperature, which helps increase the heat transfer between the hot gas and brick. In other words, it does help brick to store more heat from the hot gas, but heat transfer between brick and coke is reduced, which is opposite to the original postulation. (b) Higher brick thermal conductivity decreases brick temperature, thus increases heat transfer between hot gas and the brick layer. The heat transfer from brick to coke bed is also increased but not significantly. (c) Since usually a brick with a higher Cp value also has a higher k-value, simulation of a brick layer with both four times higher Cp and k-values actually shows a reduction in the brick temperature, and hence a degradation of the heat transfer between the brick and coke bed. Therefore, replacing the existing brick layer with a high Cp- and/or high k-value brick is not recommended.

Effect of TiO<sub>2</sub> on the Thermal Conductivity of Eco-Friendly Silica Bricks Fabricated by Yellow River Silt

Silt from the Yellow River was mixed with a certain amount of SiO2 powder to fabricate eco-friendly silica bricks and different amounts of TiO2 were added to ameliorate the thermal conductivity of the bricks. Results showed that the phases of as-fabricated silica bricks are cristobalite and tridymite with cristobalite predominating. With increasing amounts of TiO2, the bulk density and thermal conductivity of the samples increase. Although the bulk density (1.65~1.76 g/cm3 ) than the ideal density 1.85 g/cm3, the thermal conductivity is significantly ameliorated. The thermal conductivity of the sample with 1.5% TiO2 addition is 2.11 W/m.°C, which is nearly three times higher than that of commercial silica bricks (0.8 W/m.°C).

Thermal Conductivity of Earth Blocks

Materials for housing construction in developing countries are usually too expensive because most materials must be imported. In the hotter climates, especially of Africa and south Asia, coping with the heat creates another problem for designing functional housing. Construction with blocks and bricks made from a local soil has proved beneficial in the case under investigation. Previous work has shown that firing of earth blocks give the materials high crushing strengths, and the addition of cement, lime, and slag further improves the load‐bearing capacity of the blocks. The potential for enhanced thermal comfort by the addition of these additives is investigated in this paper. Thermal conductivity of plain bricks decreases with increasing firing temperature. Also, the addition of cement, lime, or slag further decreases the thermal conductivity of the bricks. The results further show that minimum thermal conductivity coincides with the condition of maximum crushing strength. Thus, the strength achievable is not compromised to obtain minimum thermal conductivity.