Experimental and Numerical Study of Mechanical Behaviour of Fired Clay Bricks after Exposure to High Temperatures

This paper reports the modeling of residual compressive strength of fired clay bricks submitted to elevated temperature. Five formulations were used and the explored temperatures were 95˚C, 200˚C, 550˚C, 700˚C and 950˚C. The stress–strain relationships and the mechanical properties (including Young’s modulus and compressive strength) were assessed using a uniaxial compressive strength machine. A proposed model equation was established and found satisfying. The elastic modulus was evaluated and tested with one existing model together with two proposed models. The proposed model was both satisfying and even more precise than the existing one. The overall results show that the effect of temperature on the mechanical properties of clays can be accurately described through the definition of thermal damage using elastic modulus.

Thermal and Mechanical Characterization of Compressed Clay Bricks Reinforced by Rice Husks for Optimizing Building in Sahelian Zone

This article deals with the characterization of local materials used in insulation building heat. These materials are bricks of earth compressed and stabilized with rice husks. Thermal conductivity, the specific heat and the thermal diffusivity of materials based on clay incorporating rate of 0, 2%, 4%, 6%, 8% and 10% are determined. The results showed that the clay blocks + rice balls had better thermal insulators than simple clay blocks. However, these composite materials used for the envelope of the building must have sufficient mechanical resistance when used in construction. The measurement of mechanical properties such as compressive strength showed an improvement of 6% and beyond, a drop in resistance when increasing rice husks in clay is observed. These results allow to specify the optimal conditions of use of these materials for the building envelope.

Structural Properties of Baked Clay Bricks Fired with Alternate Fuels

Coal is used as a traditional fuel for firing of clay bricks in kilns. The cost of coal is high and is increasing continuously. This paper describes the effect of alternate fuels on compressive strength, water absorption and density of fired clay bricks. The alternate fuels used in this study were 1) rapeseed husk (Type I), 2) combination of sugarcane-bagasse, rice husk and used clothes (Type II) and 3) coal (Type III). The results show that compressive strength of bricks fired using Type I and Type II fuels was decreased to 11% and 7%, respectively, compared to those fired with coal. However, the values of water absorption and density of bricks fired with Type I and Type II fuels were almost same as exhibited by those baked with coal. This study shows that a saving of 25%, and 18% could be achieved when the bricks were fired using Type I and Type II fuels, respectively, compared to those fired with coal.

Effect of silica fume on the behavior of lightweight reinforced concrete beams made from crushed clay bricks

Crushed over-burnt clay bricks(COBCBs)are a promising alternative to the natural gravel aggregate in lightweight concrete(LWC)production because of their high strength-to-weight ratio.Besides,COBCBs are considered a green aggregate as they solve the problem of solid waste disposal.In this paper,a total of fifteen reinforced concrete(RC)beams were constructed and tested up to failure.The experimental beams were classified into five groups.The con-trol beams were cast with normal weight concrete(NWC),while the remaining four groups of beams were prepared from LWC.The test parameters were the concrete type,reinforcement ratio and silica fume(SF)content.The behavior of beams was evaluated in terms of the crack pattern,failure mode,ultimate deflection,and ductility.The experimen-tal results suggested that the weight and strength of the concrete prepared satisfied the requirements of LWC.In addition,the increase in the reinforcement ratio and SF content improved the behavior of the beams.It is noteworthy that the SF addition caused measurable enhancements to the majority of the performance characteristics of LWC beams.Thus,COBCBs were successfully used as coarse aggregates in the production of high-quality LWC.Both ACI 318-19 and CSA-A23.3-19 made acceptable predictions of the cracking moment,ultimate capacity and mid-span deflection.

Thermal Properties of Earth Bricks Stabilised with Cement and Sawdust Residue Using the Asymmetrical Hot-Plane Method

This paper presents an experimental study of the characterisation of local materials used in the construction and thermal insulation of buildings. These materials are compressed earth bricks stabilised with cement and sawdust. The thermal conductivity, diffusivity, effusivity, and specific heat of earth-based materials containing cement or sawdust have been determined. The results show that the blocks with earth + sawdust are better thermal insulators than the blocks with simple earth. We observe an improvement in thermal efficiency depending on the presence of sawdust or cement stabilisers. For cement stabilisation, the thermal conductivity increases (λ: 1.04 to 1.36 W·m-1·K-1), the diffusivity increases (from 4.32 × 10-7 to 9.82 × 10-7 m2·s-1), and the effusivity decreases (1404 - 1096 J·m-2·K-1·s-1/2). For sawdust stabilisation, the thermal conductivity decreases (λ: 1.04 to 0.64 W·m-1·K-1), the diffusivity increases (from 4.32 × 10-7 to 5.9 × 10-7 m2·s-1), and the effusivity decreases (1404 - 906 J·m-2·K-1·s-1/2). Improving the structural and thermal efficiency of BTC via stabilisation with derived binders or cement is beneficial for the load-bearing capacity and thermal performance of buildings.

Applications of Compliance to Cost Ratio (C-CR) Analysis in the Determination of Optimum Mix of Insulating Bricks in Masonry

The scarcity of housing increases as population continues to rise all over the world. Despite government efforts at providing houses, yearly demand keeps on exceeding available houses and hence the hike in rent, the cost of erecting houses and the cost of building materials. This ultimately calls for a decisive solution. This study therefore applied compliance to cost ratio (C-CR) analysis in evaluating the optimum properties of fired ceramic bricks. The optimum mix proportions of waste glass (WG) and wood saw dust (WSD) in fired bricks, that will be suitable for housing constructions were hence determined. Fired clay brick samples which contained varied proportions of WG and WSD were examined for physical, mechanical and thermal properties in line with standard procedures. The results were compared with existing standards and property evaluation index, compliance level and C-CR were applied in analyzing the results obtained. It was observed that with increasing WG content, compliance level increased. Also, cost ratio and experimental cost of each brick sample trended upward. Sample with mix proportion;20 wt% WG, 5 wt% WSD and 75 wt% clay had compliance level of 94% and C-CR index of 7.81, hence chosen as optimum mix proportion for masonry bricks.

Effects of the Addition of Sawdust Ash and Iron Ore Tailings on the Characteristics of Clay Soil

An evaluation of the effects of additives and firing temperatures on clay bricks characteristics was studied.The two(2)additives used were sawdust ash(SDA)and iron ore tailing wastes(IOTW),and the five(5)firing temperatures of 400o C to 1200o C at intervals of 200o C were applied.The fired bricks were tested for linear shrinkage,water absorption,density,and compressive strength.The results of the investigations showed that firing temperature improved the clay brick characteristics across all replacement levels.However,the SDA additions increased the linear shrinkage and the water absorption but decreased the density and compressive strength.On the other hand,the addition of IOTW to the clay-SDA mixture,reduced both the linear shrinkage and water absorption of the clay bricks,and increased the density and compressive strength.The statistical values and the regression models derived on the experimental data using Minitab 18 Software were significant.

Blast response of clay brick masonry unit walls unreinforced and reinforced with polyurea elastomer

Clay brick masonry unit(CBMU) walls are widely used in building structures,and its damage and protection under explosion loads have been a matter of concern in the field of engineering protection.In this paper,a series of full-scale experiments of the response characteristics of 24 cm CMBU walls unreinforced and reinforced with polyurea elastomer subjected to blast loading were carried out.Through setting 5.0 kg TNT charges at different stand-off distances,the damage characteristics of masonry walls at different scaled distances were obtained.The reinforcement effect of different polyurea coating thicknesses and methods on the blast resistance performance of masonry walls under single and repeated loads were also explored.Five failure grades were summarized according to the dynamic response features of masonry walls.Based on the stress wave propagation pattern in multi-media composite structures,the internal stress distribution of masonry walls were analyzed,and the division basis of the masonry walls’ failure grades was then quantified.Combined with Scanning Electron Microscope(SEM)images,the deformation characteristics of soft and hard segments of polyurea and effects of detonation products on microstructures were revealed respectively,which provides an important reference for the design and application of polyurea in the blast resistance of clay brick masonry walls.

Mechanical and Frost-resistance Properties of Rural Area Building Waste Hollow Bricks

Serving as recycled coarse aggregate,the pretreated rural building waste was added into the concrete hollow bricks in the varying replacement of 0,20%,40%,60%,80% and 100%.By testing its compressive strength,flexural strength,mass and strength loss after freeze-thaw cycles,the impact of the different replacement on mechanical and frost-resistance properties of concrete hollow bricks was presented through SEM analysis.The experimental results show that,with the increase in recycled coarse aggregate replacement rate,the mechanical and frost-resistance properties show a downward trend;when the replacement rate is 40%,28 d compressive strength and flexural strength of concrete hollow brick demonstrate the good peak value which meet the requirement of the national standard for ordinary small concrete hollow bricks;the interfacial structures of the pretreated recycled concrete is more complicated than those of concrete made of natural aggregate,but the former enjoys better interface bonding and tight structure.

Dynamic thermal performance of multilayer hollow clay walls filled with insulation materials:Toward energy saving in hot climates

This study examines the benefits of incorporating passive techniques into multilayer hollow clay brick walls to improve their dynamic thermal performance.The finite element approach was used to solve the incompressible Navier-Stokes and energy equations to analyze the dynamic thermal response of walls exposed to real thermal excitations of the Marrakesh climate.The results show that increasing the emissivity from 0.1 to 0.9 significantly increases the total heat load over 24 h.Furthermore,filling 100% of the cavities with insulation materials delayed the temperature peak by about 2.3 h and lowered the decrement factor by roughly 43%,with a value smaller than 0.07.In addition,it is demonstrated that the total thermal load is reduced by approximately 28% for improved wall configurations(100% insulation filling cavities)compared to traditional wall configurations(100% air filling cavities),which aids in improving building energy efficiency.

Influence of Construction Materials and Building Orientation on Building Thermal Load in Hot and Dry Tropical Climate

This paper is concerned with the determination of the thermal energy performances of individual houses built with ＂H＂ shape bricks in hot and dry tropical climate （different cities of Burkina Faso and the city of Bamako in Mali）. The bricks＇ matrices include three void spaces which are filled during construction with either clay-grass mixture or with entirely clay matter. After measuring the diffusivity of the clay matter and cement bricks samples utilizing the Flash method, we determine the ＂H＂ shape bricks＇ thermal equivalent conductivity using the HEAT software. The house, modeled utilizing the TRNSYS software, reveals that, besides their economical and environmental advantages, houses constructed with ＂H＂ shape bricks filled with clay, show approximately the same energy consumption patterns as void cement bricks houses. On the other hand, houses built utilizing ＂H＂ shape bricks filled with clay-grass mixture, which have low thermal conductivity, show a reduced air conditioning load. We also study the influence of the building orientation on the energy consumption.

Influence of Recycled Construction Materials Aggregate on Mechanical and Physical Properties of Concrete

The main purpose of this research is to study the properties of re-use different types of construction materials such as PVC （polyvinylchloride） scraps, clay brick and recycled concrete as a partial replacement of coarse aggregate. Different proportions （1%, 3%, 5% and 7%） by weight were used for PVC. scrap, （10%, 20%, 30%, and 40%） by weight were used for recycled concrete and （5%, 10%, 15%, and 20%） by weight were used for clay brick. Mechanical tests such as compressive and tensile strength tests and physical tests such as ultrasonic pulse velocity, bulk density, porosity, specific gravity and water absorption tests were done to the samples after curing in normal water for 28 days. Test results showed slightly degradation in mechanical and physical engineering properties of concrete specimens that used partial replacement of recycled concrete coarse aggregate, degradation increased with increasing of replacement but test results still closely to reference samples. Use of polyvinyl chloride in proportions not more than 5% as a partial replacement of coarse aggregates given acceptable results in comparison with reference samples but all test results degraded at 7% replacements. Test results of partial replacement of crushed brick coarse aggregates unacceptable and the range of degradation are wide because of increased （water： cement） ratio to improve the concrete workability.

Laboratory evaluation of cement treated aggregate containing crushed clay brick

The waste clay bricks from debris of buildings were evaluated through lab tests as environ- mental friendly materials for pavement sub-base in the research. Five sets of coarse aggregates which contained 0, 25%, 50%, 75% and 100% crushed bricks, respectively, were blended with sand and treated by 5 % cement. The test results indicated that cement treated aggregate which contains crushed clay brick aggregate had a lower maximum dry density （MDD） and a higher optimum moisture content （OMC）. Moreover, the unconfined compressive strength （UCS）, resilience modulus, splitting strength, and frost resistance performance of the specimens decreased with increase of the amount of crushed clay brick aggregate. On the other hand, it can be observed that the use of crushed clay brick in the mixture decreased the dry shrinkage strain of the specimens. Compared with the asphalt pave- ment design specifications of China, the results imply that the substitution rate of natural aggregate with crushed clay brick aggregate in the cement treated aggregate sub-base material should be less than 50% （5 % cement content in the mixture）. Furthermore, it needs to be noted that the cement treated aggre- gate which contains crushed clay bricks should be cautiously used in the cold region due to its insuffi- cient frost resistance performance.

Traditional manufacturing of clay brick used in the historical buildings of Diyarbakir （Turkey）

Clay brick is the most common construction materia（ used in the historical buildings of Diyarbaklr （Turkey）. Many clay brick manufacturing workshops and numerous brick masters have emerged. Diyarbakir currently has two clay brick workshops that face the problem of being closed down. Therefore, manufacturing of clay brick by traditional methods may be forgotten in Diyarbakir. This study investigates the manufacturing phases of traditional clay bricks in Diyarbakir＇s local workshops, which have not been documented. The manufacturin8 phases of the clay bricks in Diyarbaklr were examined for the first time based on in-situ observations, investigations, and interviews. The research indicated the general phases of clay brick manufacturing. Raw materials are first prepared, formed, and dried. The firing of clay bricks is then performed through hacking, heating, burning, coolins, and de-hacking. The clay bricks are finally packaged and dispatched. The traditional manufacturing of clay brick methods in Diyarbaklr is similar in many regions of the world. The clay bricks are currently and extensfvely used in the restoration of historic structures. Therefore, their production must be continuous.