The utilization of solid wastes to prepare Li_(4)SiO_(4) based CO_(2) adsorbents and thermochemical energy storage(TES)materials has recently garnered significant interest.Considering practical application conditions,...The utilization of solid wastes to prepare Li_(4)SiO_(4) based CO_(2) adsorbents and thermochemical energy storage(TES)materials has recently garnered significant interest.Considering practical application conditions,the influence of CO_(2) concentration and temperature fluctuations on adsorbent performance remains a key research focus.Among various waste materials,waste clay bricks are particularly suitable for Li_(4)SiO_(4) synthesis due to their high SiO_(2) content(60% to 70%),while enabling waste valorization.Furthermore,it has been demonstrated that heteroatoms present in the waste materials positively in-fluence the CO_(2) adsorption performance of Li_(4)SiO_(4)-based adsorbents.In this study,Li_(4)SiO_(4) was syn thesized for the first time directly from waste clay bricks without pretreatment.Comprehensive characterization revealed that the resulting Li_(4)SiO_(4)-based adsorbent exhibits outstanding performance:a high CO_(2) capture capacity(27.9%(mass)),excellent cycling stability,and remarkable thermal energy storage capability(876.4 kJ·kg^(-1)).These superior properties position it as one of the most promising high-temperature adsorbents for simultaneous CO_(2) capture and thermal energy storage(TES)from fossil fuel flue gase.Moreover,the adsorbent maintained excellent stability under fluctuating temper-ature and CO_(2) concentration.Even at 20%(vol)CO_(2) and 500℃,it achieved a high capacity of 25.7%(mass),reaching equilibrium within 15 min.This CO_(2) capture performance is truly impressive.展开更多
This study was part of the framework that contributed not only to the improvement of thermal comfort in housing but also to the decarbonization of the construction and building materials industry. For this purpose, te...This study was part of the framework that contributed not only to the improvement of thermal comfort in housing but also to the decarbonization of the construction and building materials industry. For this purpose, terracotta brick seems to meet these needs. Thus, the objective of this work was to evaluate the influence of the incorporation of coal fly ash from a thermal power plant on the physical and mechanical properties of fired bricks from grey clay in the Thicky area of Senegal. The coal fly ash was incorporated into the raw clay material in proportions of 0, 5, 10, and 15 % by weight. These two raw materials were first characterized by X-ray fluorescence spectroscopy (XRF). The XRF analyses showed that the most abundant oxides in clay were SiO2 (55.034%) and Fe2O3 (10.155%). In coal fly ash, SiO2 (38.574%) is predominant. The ash also contained Al2O3 (7.717%) and alicano-earthy melting oxides such as CaO (9.271%) and MgO (7.298%) etc. These melting oxides were necessary to facilitate the formation of the liquid phase when baking platelets. The latter, when burned at a temperature of 880°C, were characterized by determining the number of physico-mechanical parameters, such as linear shrinkage during cooking, water absorption, fire loss and compressive strength. A Hierarchical Ascending Classification of these different parameters was performed and three classes were obtained. Class 1 with better compressive strength (6.358 MPa), was in sample A (5%). Class 2 consisted of sample D (reference) and had a higher plasticity index (28.51%) and water absorption rate (11.19%). Finally, class 3, which included samples B (10%) and C (15%), had very high shrinkage and fire losses compared to other platelets. These results highlighted the possibility of using up to 5% of the coal fly ash in the production of new fired bricks with good performance.展开更多
This study explores the novel application of Triumfetta pentandra(TP,“Nkui”)fibers,a tropical plant that is abundant yet underutilized in civil engineering,to enhance the performance of compressed earth bricks(CEBs)...This study explores the novel application of Triumfetta pentandra(TP,“Nkui”)fibers,a tropical plant that is abundant yet underutilized in civil engineering,to enhance the performance of compressed earth bricks(CEBs).The main objective is to assess how incorporating these vegetal fibers can improve the mechanical properties of CEBs while maintaining durability.TP fibers were extracted,characterized,and integrated into the soil used for brick specimens.A rigorous experimental protocol was implemented,featuring a unique fiber pre-treatment,the use of a single,homogeneous clayey soil type,and controlled 28-day curing under standard humidity and temperature,which distinguishes this study from previous works.Physical measurements(moisture content,bulk density,water absorption)and mechanical tests(fiber tensile strength,compressive and flexural strength of CEBs)were conducted following French standards.The results indicate that 4%TP fiber content yields optimal mechanical performance,with compressive strength reaching 6.61 MPa and flexural strength 1.49 MPa at 28 days,compared to 5.16 MPa and 0.51 MPa for unreinforced samples.This demonstrates the potential of TP fibers to reinforce earth-based materials,providing a sustainable,locally sourced,and cost-effective construction solution.However,higher fiber content increases porosity and capillary water absorption(up to 16.75 g at 6%fibers),highlighting the importance of optimized fiber dosing and potential complementary treatments for long-term durability.展开更多
建立了由一个制造商和一个分销商组成的基于电子市场的二级供应链模型,讨论了分销商采用Bricks and Clicks模式分销产品,并在电子渠道进行季节后销售的情况,分析了供应链的契约协调问题及供应链成员的利润情况.研究发现改进的回购契约...建立了由一个制造商和一个分销商组成的基于电子市场的二级供应链模型,讨论了分销商采用Bricks and Clicks模式分销产品,并在电子渠道进行季节后销售的情况,分析了供应链的契约协调问题及供应链成员的利润情况.研究发现改进的回购契约可以使Bricks and Clicks分销模式下基于电子市场的二级供应链模型达到协调,使分销商的订货量达到供应链最优,并且使供应链成员的利润达到Pareto改进,达到"双赢".最后,通过算例验证了结论.展开更多
The aim of this study is to enhance the value of local earth materials used in the construction of certain homes in the Republic of Guinea. Thus, a trial study to improve the quality of mud bricks using paper fibers o...The aim of this study is to enhance the value of local earth materials used in the construction of certain homes in the Republic of Guinea. Thus, a trial study to improve the quality of mud bricks using paper fibers obtained by grinding and soaking in water and then drying were used as a stabilizer in the manufacture of these mud bricks from the sample of two sites Dounkiwal (DK) (in Mamou and the sample from the urban commune of Kouroussa). To do this, certain methods and means of identification were carried out, namely: geotechnical, mineralogical and chemical analyses. Sample DK from Mamou has a silty-clay geotechnical characteristic with a plasticity index Ip of 12.75%. However, mineralogical and chemical studies showed that sample Dounkiwal (DK) (Mamou) contains a high proportion of silica and iron oxides (79.63%) and Fe2O3 (11.85%), associated with other alkaline earth oxides and ions: CaO;MgO;SO32−;Cl−, i.e. 3.96%;0.96%;0.28% and 0.039% respectively. Its loss on ignition (LOI) and insoluble residues are 15.40% and 56.36%. The evaluation of the number of huts in Upper and Middle Guinea showed that the populations of these areas have been using mud bricks for several decades in the construction of dwellings. The average value found for the compressive strength of these bricks (from samples I, II and III from Kouroussa) is 0.16 MPa. This value is appreciable in the construction of mud houses.展开更多
This study evaluates the influence of sand content on the mechanical behavior and water resistance of compressed earth bricks(CEBs)manufactured from Lendi clay(Douala,Cameroon).Twenty-seven specimens(prismatic and cub...This study evaluates the influence of sand content on the mechanical behavior and water resistance of compressed earth bricks(CEBs)manufactured from Lendi clay(Douala,Cameroon).Twenty-seven specimens(prismatic and cubic)were produced with three formulations:0%,30%and 60%sand substitution by dry mass,compacted at 2.5 MPa and cured for 7,14 and 28 days.Raw material characterization included particle size distribution,sand equivalent,Atterberg limits,bulk density and Proctor compaction.The clay displayed a liquid limit of 44.07%,plastic limit of 35.23%and plasticity index of 8.84%;optimum moisture content was 15.9%and maximum dry density 1.24 g·cm^(-3).Mechanical testing showed that pure-clay bricks achieved the highest compressive and flexural strengths at all ages(up to≈1.98 MPa and 0.56 MPa respectively).Although the 30%sand mix exhibited marginally higher early compressive strength(7 days),strength decreased substantially by 28 days.Capillary absorption tests revealed an important distinction:while 0%sand bricks exhibited continuous water uptake,they retained cohesion during immersion;conversely,30%and 60%sand bricks disintegrated into a slurry within seconds of immersion,evidencing severe loss of internal bonding.These findings indicate that,for this highly plastic tropical clay,sand acts primarily as a microstructural diluent that undermines long-term cohesion and durability despite short-term packing benefits.The study underscores the need for locally tailored formulations or stabilizers when designing durable CEBs for humid tropical climates.展开更多
In this study,the feasibility of producing eco-friendly bricks by using geopolymer technology and a waste grinding wheel(WGW)from the grinding wheel industries was investigated.Nowadays,in order to meet industrial nee...In this study,the feasibility of producing eco-friendly bricks by using geopolymer technology and a waste grinding wheel(WGW)from the grinding wheel industries was investigated.Nowadays,in order to meet industrial needs,for instance,in Taiwan,approximately 500,000 grinding wheels are used annually.That is,a large number of“waste”grinding wheels are produced.Furthermore,few studies have been conducted on the use of WGWs as raw materials in geopolymer applications.The use of geopolymer technology to form bricks can avoid the utilization of clay and cement and even prevent the use of a high-temperature process in kilns.Moreover,it can decrease CO_(2) emission and energy consumption and thus,protect the environment.In this study,the following three major factors were considered:press-forming pressure(70 and 100 kgf/cm2),NaOH molar concentration(2 and 4M),and the ratio of binder fineaggregate(1:3,1:4,and 1:5).Under these conditions,the specimens were tested using the compressive strength test,water absorption test,microstructure analysis,a freezing–thawing test and toxicity characteristic leaching procedure test.The optimal formulation was composed of 1:4 binder fine-aggregate ratio,4M NaOH concentration,and 100-kgf/cm2 pressure.Furthermore,we used a WGW and achieved a compressive strength of 50.6 MPa after 28 days,which was greater than 32 MPa and conformed to the Grade A brick standard of National Standards of the Republic of China(13295).In conclusion,this brick fabrication method based on geopolymer technology was not only beneficial to the environment but also improved the efficiency of reutilizing WGW.展开更多
This paper correlates the use of building blocks with the shape grammar theory in the design process. The main goal is to present the potentialities of the various building blocks, which combined with Shape grammar ca...This paper correlates the use of building blocks with the shape grammar theory in the design process. The main goal is to present the potentialities of the various building blocks, which combined with Shape grammar can contribute to the creative process, particularly for the formal composition in the field of Architecture, Urbanism and Design. The methodology is based on a literature review and reflections derived from the observations of the use of the building blocks during experiments carried out in the scope of research with students of the undergraduate course in Architecture and Urbanism. Starting from the discussions proposed by George Stiny on design with Froebel’s buildings gifts and from experiments with other building blocks, such as Archbricks, it is found that building blocks have their own vocabulary and rules, which can be appropriated and exploited by designers in the construction of new shape grammars.展开更多
Currently the service life of CDQ shafts in China is mainly restricted by the properties of the inclined flue bricks.In this work,based on the systematic analysis of the damage mechanism of inclined flue refractories,...Currently the service life of CDQ shafts in China is mainly restricted by the properties of the inclined flue bricks.In this work,based on the systematic analysis of the damage mechanism of inclined flue refractories,high performance mullite-SiC bricks were developed.The bricks were produced by corundum,andalusite,SiC and other high purity raw materials.Metal silicon and alumina ultra micropowder were added to form dispersion multi-phase structure,fortifying the matrix and improving the microstructure.The products have excellent properties such as low porosity,high density,good wear resistance,high refractoriness under load,and good thermal shock resistance.The products can replace the ordinary mullite-SiC bricks and obtain a good service life.展开更多
In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositio...In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositions and microstructures were tested by XRD,SEM and EPMA.The experimental results show that the water absorption is 45.64%,the porosity is 58.91%,bulk density is 1.29 g·cm-3,compressive strength is 54.91 MPa,bending strength is 29.52 MPa,freeze-thaw resistance is 29.28 MPa,specific heat capacity at constant pressure is 1.31 J·g-1·K-1,thermal diffusivity is 5.89×10-3 cm2·s-1,and thermal conductivity is 1.15×10-2 W·cm-1·K-1.These effects of additives and preparation process to the properties and microstructures were discussed in detail.The reaction mechanism was also discussed.The results of the reaction mechanism show that there has wollastonite and feldspar generated during the process of firing while Ca gathered around the feldspar,and then Ca would displace K and generated cacoclasite.展开更多
The high chrome bricks specimens were prepared by firing at 1 350,1 450 and 1 550 ℃ in carbon embedded condition and at 1 700 ℃ in air,respectively. Effects of firing atmospheres （carbon embedded and air） on bulk ...The high chrome bricks specimens were prepared by firing at 1 350,1 450 and 1 550 ℃ in carbon embedded condition and at 1 700 ℃ in air,respectively. Effects of firing atmospheres （carbon embedded and air） on bulk density,apparent porosity,cold crushing strength,and slag penetration resistance of high chrome bricks were researched in order to improve physical properties and corrosion resistance of high chrome bricks and to prolong the service life in slagging coal gasifier. The results show that with temperature rising,the apparent porosity of specimens decreases and the bulk density increases; the cold crushing strength of the specimens carbon embedded fired at 1 450 ℃ is the highest,reaching 214 MPa; carbon embedded condition is beneficial to reducing the sintering temperature and improving the microstructure; the specimens carbon embedded fired at 1 450 ℃ perform better slag penetration resistance than the specimens fired at 1 700 ℃ in air.展开更多
The microstructure and properties of phosphate bonded Cr2O3 - -Al2O3 - ZrO2 specimens fired in air or coke bed were investigated firstly. Then property change of the Cr2 O3 - Al2 O3 - ZrO2 bricks after secondary treat...The microstructure and properties of phosphate bonded Cr2O3 - -Al2O3 - ZrO2 specimens fired in air or coke bed were investigated firstly. Then property change of the Cr2 O3 - Al2 O3 - ZrO2 bricks after secondary treat- ment in simulation environment was studied. Finally, corrosion resistances of the Cr2 O3 - Al2 O3 - ZrO2 bricks in air and simulation environment were compared; and microstructure of on-site used Cr2O3 - Al2O3 - ZrO2 bricks in slagging gasifiers was analyzed. The results show that the atmosphere has significant effect on the mi- crostructure and properties of the phosphate bonded Cr2O3 -Al2O3 -ZrO2 bricks. As the specimens are fired in air, the phosphate forms a composite solid solution with Cr2 O3 and Al2 O3, therefore, strength of the speci- mens is enhanced. For specimens fired in coke bed, a certain amount of gases are generated owing to the re- duction of phosphate and part of Cr2 O3, which results in the increasing number and size of the pores, bad interfa- cial bonding between Cr2O3 aggregates and matrix as well as low strength of the specimens. During service process in reducing atmosphere, the phosphate binder and part of Cr2O3 in edge of the specimens are also re- duced, leading to significant increase of number and size of the pores in the edge of the specimens; as a result, inreducing atmosphere, the specimens show much worse corrosion resistance than in air.展开更多
The annual output of China ' s silica brick amounts up to over 300 thousand tons, which accounts for more than 10% of the total output of silica bricks in the world. Besides satisfying domestic markets , China s s...The annual output of China ' s silica brick amounts up to over 300 thousand tons, which accounts for more than 10% of the total output of silica bricks in the world. Besides satisfying domestic markets , China s silica bricks have been exported to many countries and regions such as Japan, USA etc. In this paper, the situation of silica bricks production, technology, sales and exporting have been described. Also suggestions on improvement of silica bricks quality and exporting, corporation with foreign partners have been put forward in order to win larger market share both at home and abroad.展开更多
Particle size analysis, Atterberg limits, X-ray diffraction, X-ray fluorescence and firing tests were used to determine physico-chemical, mineralogical and technological characteristics of residual lateritic (K1M, Ma2...Particle size analysis, Atterberg limits, X-ray diffraction, X-ray fluorescence and firing tests were used to determine physico-chemical, mineralogical and technological characteristics of residual lateritic (K1M, Ma2) and alluvial (KB3, KG3) clays from Foumban (West-Cameroon). For technological properties, the samples were pressed and fired over a temperature range of 900°C - 1200°C to determine the open porosity, linear shrinkage, bulk density and compressive strength. Kaolinite (31% - 65%) and quartz (35% - 50%) are dominant in Foumban clays with accessory K-feldspar, plagioclase, illite, smectite, rutile, and goethite. But their proportion changes from one sample to another, having a significant effect on the behaviour of the clay materials: highest proportion of quartz (50%) in sample K1M;relative high feldspars (20%) and illite contents (10%) in KB3 and MA2;high smectite content in KG3 (up to 20%). Chemical analyses indicate high SiO2 (49% - 77%) and low Al2O3 (14% - 23%) contents in the four samples, with comparatively low contents of iron oxides (4% - 7% in samples KB3 and KG3, 2.5% in MA2 and ~1.5% in sample K1M). The particle size distribution of the alluvial clays (KG3 and KB3) differs considerably: 7% to 37% of clay fraction, 20% to 78% of silt, and 15% to 58% of sand, while residual clays (K1M and MA2) present on average 12% of clay, 51% of silt and 37% of sand. Two raw clays (KB3 and MA2) can be used for bricks/tiles production without beneficiation or addition. K1M requires some flux addition to decrease the sintering temperature while KG3 presents poor properties due to the combined occurrence of smectite and a high clayey fraction (37%). Such mineralogical composition is responsible for very high plasticity (PI: 50), high shrinkage (LS: 5% - 16%), low porosity (OP: up to 21%) and high flexural strength (FS: 16 - 23 N/mm2) above 1050°C. This last clay is therefore less appropriate for bricks and roofing tiles production since degreasers must be added to the raw material.展开更多
Heat conduction through conventional and interlocking building bricks with cavities was studied in this work. Heat transfer analysis was carried out using MATLAB? partial differential equation toolbox. Regular and sta...Heat conduction through conventional and interlocking building bricks with cavities was studied in this work. Heat transfer analysis was carried out using MATLAB? partial differential equation toolbox. Regular and staggered hole arrangements were studied. Results showed that four staggered holed interlocking bricks were effective in thermal resistance into the bricks and increasing the holes beyond four did not give any thermal resistance advantage. For the conventional bricks staggered holes did not give any thermal resistance advantage but the four-holed bricks were also adjudged to be effective in thermal resistance into the brick surface. Increasing the number of holes beyond four in conventional bricks did give some thermal resistivity advantage but very minimal. Structural strengths of holed bricks were not considered in this study.展开更多
This study compares the effect of treated pineapple leaves fibres (T-PALF) with sodium hydroxide solution and untreated fibres (N-PALF) on the compressive and flexural strength of earth bricks stabilized with 3% and 5...This study compares the effect of treated pineapple leaves fibres (T-PALF) with sodium hydroxide solution and untreated fibres (N-PALF) on the compressive and flexural strength of earth bricks stabilized with 3% and 5% cement. The fibre content ranged from 0% to 5% in steps of 1% by weight. The compressive strength tests were made at 7, 14, 21 and 28 days of curing;the flexural strength test were conducted at 28th day only. The results show that the T-PALF had a higher compressive strength when comparing to the N-PALF. The highest compressive strength of the bricks was obtained at 28 days of curing. The compressive strength at 28 days of stabilized brick at 3% and 5% of cement reinforced with T-PALF were 4.01 and 4.81 MPa, respectively, while the one reinforced with N-PALF was 3.19 and 4.63 MPa, respectively. The results further show that the highest flexural strength of both stabilized bricks at 3% and 5% of cement reinforced with T-PALF and N-PALF was obtained with the bricks stabilized with 5% of cement reinforced with T-PALF. This results show that bricks stabilized with 5% cement and reinforced with 3% of treated fibres content are good for construction of load bearing walls. It was observed;a significant improvement of the reinforced blocks under flexure than under compression.展开更多
This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hyd...This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hydrogen atmosphere at 1100°C,we tried to find out the minute changes.In this experiment,a refractory brick was prepared by andalusite,mullite chamotte,and clay as raw materials and heated to 1100°C in a 100%hydrogen atmosphere for 72 h.It was found that the strength of the brick was decreased and the color was changed to black by the reduction of impurities.And in addition,this study covered research on the slaking risk of MgO raw materials because the minimum temperature is expected to 400°C in fluidized reduction furnaces unlike shaft furnaces.展开更多
Thatch fibres grow in large quantity in the Adamawa region of Cameroon. During the long dry season, these fibres cause numerous fire incidents, which not only devastate large areas of cash crops, but also contribute t...Thatch fibres grow in large quantity in the Adamawa region of Cameroon. During the long dry season, these fibres cause numerous fire incidents, which not only devastate large areas of cash crops, but also contribute to increase emissions of greenhouse gases into the atmosphere. This article aims to show how fibres could be used with compressed clay bricks to manufacture an insulating material used in building. Four fibre contents 1%, 2%, 3% and 4% made up the sample studied. The asymmetric hot plate methodology was used to determine the thermophysical properties of these composite materials. The volumetric heat capacity and the thermal effusivity of these materials were estimated. These two parametres were used to determine their apparent thermal conductivities. The results obtained show that the thermal conductivity decreases as the volume of fibres in the mixture increases. It is 0.689 W·m-1·K-1 for simple compressed clay bricks and 0.510 W·m-1·K-1 for a dosage at 3% of thatch fibres. In a bit to validate the results of the pilot study of the apparent thermal conductivity, the heat mass capacity of this composite material was achieved through the use of the dehydration method. The relative difference obtained with the results of the volumetric heat capacity carried out with these two methods was good. All results showed that the use of fibres in compressed laterite brick gives a more insulating composite material that respects Civil Engineering Norms.展开更多
基金the National Natural Science Foundation of China(5240101142)Yunnan Province basic research project(202401CF070252)+1 种基金the Key R&D plan of Yunnan Province(202303AC100008)the Scientific Researching Fund Projects of Yunnan Provincial Department of Education(2025J0077),which funded this study。
文摘The utilization of solid wastes to prepare Li_(4)SiO_(4) based CO_(2) adsorbents and thermochemical energy storage(TES)materials has recently garnered significant interest.Considering practical application conditions,the influence of CO_(2) concentration and temperature fluctuations on adsorbent performance remains a key research focus.Among various waste materials,waste clay bricks are particularly suitable for Li_(4)SiO_(4) synthesis due to their high SiO_(2) content(60% to 70%),while enabling waste valorization.Furthermore,it has been demonstrated that heteroatoms present in the waste materials positively in-fluence the CO_(2) adsorption performance of Li_(4)SiO_(4)-based adsorbents.In this study,Li_(4)SiO_(4) was syn thesized for the first time directly from waste clay bricks without pretreatment.Comprehensive characterization revealed that the resulting Li_(4)SiO_(4)-based adsorbent exhibits outstanding performance:a high CO_(2) capture capacity(27.9%(mass)),excellent cycling stability,and remarkable thermal energy storage capability(876.4 kJ·kg^(-1)).These superior properties position it as one of the most promising high-temperature adsorbents for simultaneous CO_(2) capture and thermal energy storage(TES)from fossil fuel flue gase.Moreover,the adsorbent maintained excellent stability under fluctuating temper-ature and CO_(2) concentration.Even at 20%(vol)CO_(2) and 500℃,it achieved a high capacity of 25.7%(mass),reaching equilibrium within 15 min.This CO_(2) capture performance is truly impressive.
文摘This study was part of the framework that contributed not only to the improvement of thermal comfort in housing but also to the decarbonization of the construction and building materials industry. For this purpose, terracotta brick seems to meet these needs. Thus, the objective of this work was to evaluate the influence of the incorporation of coal fly ash from a thermal power plant on the physical and mechanical properties of fired bricks from grey clay in the Thicky area of Senegal. The coal fly ash was incorporated into the raw clay material in proportions of 0, 5, 10, and 15 % by weight. These two raw materials were first characterized by X-ray fluorescence spectroscopy (XRF). The XRF analyses showed that the most abundant oxides in clay were SiO2 (55.034%) and Fe2O3 (10.155%). In coal fly ash, SiO2 (38.574%) is predominant. The ash also contained Al2O3 (7.717%) and alicano-earthy melting oxides such as CaO (9.271%) and MgO (7.298%) etc. These melting oxides were necessary to facilitate the formation of the liquid phase when baking platelets. The latter, when burned at a temperature of 880°C, were characterized by determining the number of physico-mechanical parameters, such as linear shrinkage during cooking, water absorption, fire loss and compressive strength. A Hierarchical Ascending Classification of these different parameters was performed and three classes were obtained. Class 1 with better compressive strength (6.358 MPa), was in sample A (5%). Class 2 consisted of sample D (reference) and had a higher plasticity index (28.51%) and water absorption rate (11.19%). Finally, class 3, which included samples B (10%) and C (15%), had very high shrinkage and fire losses compared to other platelets. These results highlighted the possibility of using up to 5% of the coal fly ash in the production of new fired bricks with good performance.
文摘This study explores the novel application of Triumfetta pentandra(TP,“Nkui”)fibers,a tropical plant that is abundant yet underutilized in civil engineering,to enhance the performance of compressed earth bricks(CEBs).The main objective is to assess how incorporating these vegetal fibers can improve the mechanical properties of CEBs while maintaining durability.TP fibers were extracted,characterized,and integrated into the soil used for brick specimens.A rigorous experimental protocol was implemented,featuring a unique fiber pre-treatment,the use of a single,homogeneous clayey soil type,and controlled 28-day curing under standard humidity and temperature,which distinguishes this study from previous works.Physical measurements(moisture content,bulk density,water absorption)and mechanical tests(fiber tensile strength,compressive and flexural strength of CEBs)were conducted following French standards.The results indicate that 4%TP fiber content yields optimal mechanical performance,with compressive strength reaching 6.61 MPa and flexural strength 1.49 MPa at 28 days,compared to 5.16 MPa and 0.51 MPa for unreinforced samples.This demonstrates the potential of TP fibers to reinforce earth-based materials,providing a sustainable,locally sourced,and cost-effective construction solution.However,higher fiber content increases porosity and capillary water absorption(up to 16.75 g at 6%fibers),highlighting the importance of optimized fiber dosing and potential complementary treatments for long-term durability.
文摘建立了由一个制造商和一个分销商组成的基于电子市场的二级供应链模型,讨论了分销商采用Bricks and Clicks模式分销产品,并在电子渠道进行季节后销售的情况,分析了供应链的契约协调问题及供应链成员的利润情况.研究发现改进的回购契约可以使Bricks and Clicks分销模式下基于电子市场的二级供应链模型达到协调,使分销商的订货量达到供应链最优,并且使供应链成员的利润达到Pareto改进,达到"双赢".最后,通过算例验证了结论.
文摘The aim of this study is to enhance the value of local earth materials used in the construction of certain homes in the Republic of Guinea. Thus, a trial study to improve the quality of mud bricks using paper fibers obtained by grinding and soaking in water and then drying were used as a stabilizer in the manufacture of these mud bricks from the sample of two sites Dounkiwal (DK) (in Mamou and the sample from the urban commune of Kouroussa). To do this, certain methods and means of identification were carried out, namely: geotechnical, mineralogical and chemical analyses. Sample DK from Mamou has a silty-clay geotechnical characteristic with a plasticity index Ip of 12.75%. However, mineralogical and chemical studies showed that sample Dounkiwal (DK) (Mamou) contains a high proportion of silica and iron oxides (79.63%) and Fe2O3 (11.85%), associated with other alkaline earth oxides and ions: CaO;MgO;SO32−;Cl−, i.e. 3.96%;0.96%;0.28% and 0.039% respectively. Its loss on ignition (LOI) and insoluble residues are 15.40% and 56.36%. The evaluation of the number of huts in Upper and Middle Guinea showed that the populations of these areas have been using mud bricks for several decades in the construction of dwellings. The average value found for the compressive strength of these bricks (from samples I, II and III from Kouroussa) is 0.16 MPa. This value is appreciable in the construction of mud houses.
文摘This study evaluates the influence of sand content on the mechanical behavior and water resistance of compressed earth bricks(CEBs)manufactured from Lendi clay(Douala,Cameroon).Twenty-seven specimens(prismatic and cubic)were produced with three formulations:0%,30%and 60%sand substitution by dry mass,compacted at 2.5 MPa and cured for 7,14 and 28 days.Raw material characterization included particle size distribution,sand equivalent,Atterberg limits,bulk density and Proctor compaction.The clay displayed a liquid limit of 44.07%,plastic limit of 35.23%and plasticity index of 8.84%;optimum moisture content was 15.9%and maximum dry density 1.24 g·cm^(-3).Mechanical testing showed that pure-clay bricks achieved the highest compressive and flexural strengths at all ages(up to≈1.98 MPa and 0.56 MPa respectively).Although the 30%sand mix exhibited marginally higher early compressive strength(7 days),strength decreased substantially by 28 days.Capillary absorption tests revealed an important distinction:while 0%sand bricks exhibited continuous water uptake,they retained cohesion during immersion;conversely,30%and 60%sand bricks disintegrated into a slurry within seconds of immersion,evidencing severe loss of internal bonding.These findings indicate that,for this highly plastic tropical clay,sand acts primarily as a microstructural diluent that undermines long-term cohesion and durability despite short-term packing benefits.The study underscores the need for locally tailored formulations or stabilizers when designing durable CEBs for humid tropical climates.
文摘In this study,the feasibility of producing eco-friendly bricks by using geopolymer technology and a waste grinding wheel(WGW)from the grinding wheel industries was investigated.Nowadays,in order to meet industrial needs,for instance,in Taiwan,approximately 500,000 grinding wheels are used annually.That is,a large number of“waste”grinding wheels are produced.Furthermore,few studies have been conducted on the use of WGWs as raw materials in geopolymer applications.The use of geopolymer technology to form bricks can avoid the utilization of clay and cement and even prevent the use of a high-temperature process in kilns.Moreover,it can decrease CO_(2) emission and energy consumption and thus,protect the environment.In this study,the following three major factors were considered:press-forming pressure(70 and 100 kgf/cm2),NaOH molar concentration(2 and 4M),and the ratio of binder fineaggregate(1:3,1:4,and 1:5).Under these conditions,the specimens were tested using the compressive strength test,water absorption test,microstructure analysis,a freezing–thawing test and toxicity characteristic leaching procedure test.The optimal formulation was composed of 1:4 binder fine-aggregate ratio,4M NaOH concentration,and 100-kgf/cm2 pressure.Furthermore,we used a WGW and achieved a compressive strength of 50.6 MPa after 28 days,which was greater than 32 MPa and conformed to the Grade A brick standard of National Standards of the Republic of China(13295).In conclusion,this brick fabrication method based on geopolymer technology was not only beneficial to the environment but also improved the efficiency of reutilizing WGW.
文摘This paper correlates the use of building blocks with the shape grammar theory in the design process. The main goal is to present the potentialities of the various building blocks, which combined with Shape grammar can contribute to the creative process, particularly for the formal composition in the field of Architecture, Urbanism and Design. The methodology is based on a literature review and reflections derived from the observations of the use of the building blocks during experiments carried out in the scope of research with students of the undergraduate course in Architecture and Urbanism. Starting from the discussions proposed by George Stiny on design with Froebel’s buildings gifts and from experiments with other building blocks, such as Archbricks, it is found that building blocks have their own vocabulary and rules, which can be appropriated and exploited by designers in the construction of new shape grammars.
文摘Currently the service life of CDQ shafts in China is mainly restricted by the properties of the inclined flue bricks.In this work,based on the systematic analysis of the damage mechanism of inclined flue refractories,high performance mullite-SiC bricks were developed.The bricks were produced by corundum,andalusite,SiC and other high purity raw materials.Metal silicon and alumina ultra micropowder were added to form dispersion multi-phase structure,fortifying the matrix and improving the microstructure.The products have excellent properties such as low porosity,high density,good wear resistance,high refractoriness under load,and good thermal shock resistance.The products can replace the ordinary mullite-SiC bricks and obtain a good service life.
基金Funded by the 11th Five-Year National Key Technology R&D Program(2008BAC41B00)
文摘In order to utilize solid wastes,ceramic simple bricks with high performances were made from industrial solid wastes such as red mud,fly ash and poor clay shale as main raw materials in this paper.The phase compositions and microstructures were tested by XRD,SEM and EPMA.The experimental results show that the water absorption is 45.64%,the porosity is 58.91%,bulk density is 1.29 g·cm-3,compressive strength is 54.91 MPa,bending strength is 29.52 MPa,freeze-thaw resistance is 29.28 MPa,specific heat capacity at constant pressure is 1.31 J·g-1·K-1,thermal diffusivity is 5.89×10-3 cm2·s-1,and thermal conductivity is 1.15×10-2 W·cm-1·K-1.These effects of additives and preparation process to the properties and microstructures were discussed in detail.The reaction mechanism was also discussed.The results of the reaction mechanism show that there has wollastonite and feldspar generated during the process of firing while Ca gathered around the feldspar,and then Ca would displace K and generated cacoclasite.
文摘The high chrome bricks specimens were prepared by firing at 1 350,1 450 and 1 550 ℃ in carbon embedded condition and at 1 700 ℃ in air,respectively. Effects of firing atmospheres （carbon embedded and air） on bulk density,apparent porosity,cold crushing strength,and slag penetration resistance of high chrome bricks were researched in order to improve physical properties and corrosion resistance of high chrome bricks and to prolong the service life in slagging coal gasifier. The results show that with temperature rising,the apparent porosity of specimens decreases and the bulk density increases; the cold crushing strength of the specimens carbon embedded fired at 1 450 ℃ is the highest,reaching 214 MPa; carbon embedded condition is beneficial to reducing the sintering temperature and improving the microstructure; the specimens carbon embedded fired at 1 450 ℃ perform better slag penetration resistance than the specimens fired at 1 700 ℃ in air.
文摘The microstructure and properties of phosphate bonded Cr2O3 - -Al2O3 - ZrO2 specimens fired in air or coke bed were investigated firstly. Then property change of the Cr2 O3 - Al2 O3 - ZrO2 bricks after secondary treat- ment in simulation environment was studied. Finally, corrosion resistances of the Cr2 O3 - Al2 O3 - ZrO2 bricks in air and simulation environment were compared; and microstructure of on-site used Cr2O3 - Al2O3 - ZrO2 bricks in slagging gasifiers was analyzed. The results show that the atmosphere has significant effect on the mi- crostructure and properties of the phosphate bonded Cr2O3 -Al2O3 -ZrO2 bricks. As the specimens are fired in air, the phosphate forms a composite solid solution with Cr2 O3 and Al2 O3, therefore, strength of the speci- mens is enhanced. For specimens fired in coke bed, a certain amount of gases are generated owing to the re- duction of phosphate and part of Cr2 O3, which results in the increasing number and size of the pores, bad interfa- cial bonding between Cr2O3 aggregates and matrix as well as low strength of the specimens. During service process in reducing atmosphere, the phosphate binder and part of Cr2O3 in edge of the specimens are also re- duced, leading to significant increase of number and size of the pores in the edge of the specimens; as a result, inreducing atmosphere, the specimens show much worse corrosion resistance than in air.
文摘The annual output of China ' s silica brick amounts up to over 300 thousand tons, which accounts for more than 10% of the total output of silica bricks in the world. Besides satisfying domestic markets , China s silica bricks have been exported to many countries and regions such as Japan, USA etc. In this paper, the situation of silica bricks production, technology, sales and exporting have been described. Also suggestions on improvement of silica bricks quality and exporting, corporation with foreign partners have been put forward in order to win larger market share both at home and abroad.
文摘Particle size analysis, Atterberg limits, X-ray diffraction, X-ray fluorescence and firing tests were used to determine physico-chemical, mineralogical and technological characteristics of residual lateritic (K1M, Ma2) and alluvial (KB3, KG3) clays from Foumban (West-Cameroon). For technological properties, the samples were pressed and fired over a temperature range of 900°C - 1200°C to determine the open porosity, linear shrinkage, bulk density and compressive strength. Kaolinite (31% - 65%) and quartz (35% - 50%) are dominant in Foumban clays with accessory K-feldspar, plagioclase, illite, smectite, rutile, and goethite. But their proportion changes from one sample to another, having a significant effect on the behaviour of the clay materials: highest proportion of quartz (50%) in sample K1M;relative high feldspars (20%) and illite contents (10%) in KB3 and MA2;high smectite content in KG3 (up to 20%). Chemical analyses indicate high SiO2 (49% - 77%) and low Al2O3 (14% - 23%) contents in the four samples, with comparatively low contents of iron oxides (4% - 7% in samples KB3 and KG3, 2.5% in MA2 and ~1.5% in sample K1M). The particle size distribution of the alluvial clays (KG3 and KB3) differs considerably: 7% to 37% of clay fraction, 20% to 78% of silt, and 15% to 58% of sand, while residual clays (K1M and MA2) present on average 12% of clay, 51% of silt and 37% of sand. Two raw clays (KB3 and MA2) can be used for bricks/tiles production without beneficiation or addition. K1M requires some flux addition to decrease the sintering temperature while KG3 presents poor properties due to the combined occurrence of smectite and a high clayey fraction (37%). Such mineralogical composition is responsible for very high plasticity (PI: 50), high shrinkage (LS: 5% - 16%), low porosity (OP: up to 21%) and high flexural strength (FS: 16 - 23 N/mm2) above 1050°C. This last clay is therefore less appropriate for bricks and roofing tiles production since degreasers must be added to the raw material.
文摘Heat conduction through conventional and interlocking building bricks with cavities was studied in this work. Heat transfer analysis was carried out using MATLAB? partial differential equation toolbox. Regular and staggered hole arrangements were studied. Results showed that four staggered holed interlocking bricks were effective in thermal resistance into the bricks and increasing the holes beyond four did not give any thermal resistance advantage. For the conventional bricks staggered holes did not give any thermal resistance advantage but the four-holed bricks were also adjudged to be effective in thermal resistance into the brick surface. Increasing the number of holes beyond four in conventional bricks did give some thermal resistivity advantage but very minimal. Structural strengths of holed bricks were not considered in this study.
文摘This study compares the effect of treated pineapple leaves fibres (T-PALF) with sodium hydroxide solution and untreated fibres (N-PALF) on the compressive and flexural strength of earth bricks stabilized with 3% and 5% cement. The fibre content ranged from 0% to 5% in steps of 1% by weight. The compressive strength tests were made at 7, 14, 21 and 28 days of curing;the flexural strength test were conducted at 28th day only. The results show that the T-PALF had a higher compressive strength when comparing to the N-PALF. The highest compressive strength of the bricks was obtained at 28 days of curing. The compressive strength at 28 days of stabilized brick at 3% and 5% of cement reinforced with T-PALF were 4.01 and 4.81 MPa, respectively, while the one reinforced with N-PALF was 3.19 and 4.63 MPa, respectively. The results further show that the highest flexural strength of both stabilized bricks at 3% and 5% of cement reinforced with T-PALF and N-PALF was obtained with the bricks stabilized with 5% of cement reinforced with T-PALF. This results show that bricks stabilized with 5% cement and reinforced with 3% of treated fibres content are good for construction of load bearing walls. It was observed;a significant improvement of the reinforced blocks under flexure than under compression.
基金supported by the Korea Planning & Evaluation Institute of Industrial Technology (KEIT)the Ministry of Trade, Industry & Energy (MOTIE, Korea) of the Republic of Korea (No. RS2023-00262421)
文摘This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hydrogen atmosphere at 1100°C,we tried to find out the minute changes.In this experiment,a refractory brick was prepared by andalusite,mullite chamotte,and clay as raw materials and heated to 1100°C in a 100%hydrogen atmosphere for 72 h.It was found that the strength of the brick was decreased and the color was changed to black by the reduction of impurities.And in addition,this study covered research on the slaking risk of MgO raw materials because the minimum temperature is expected to 400°C in fluidized reduction furnaces unlike shaft furnaces.
文摘Thatch fibres grow in large quantity in the Adamawa region of Cameroon. During the long dry season, these fibres cause numerous fire incidents, which not only devastate large areas of cash crops, but also contribute to increase emissions of greenhouse gases into the atmosphere. This article aims to show how fibres could be used with compressed clay bricks to manufacture an insulating material used in building. Four fibre contents 1%, 2%, 3% and 4% made up the sample studied. The asymmetric hot plate methodology was used to determine the thermophysical properties of these composite materials. The volumetric heat capacity and the thermal effusivity of these materials were estimated. These two parametres were used to determine their apparent thermal conductivities. The results obtained show that the thermal conductivity decreases as the volume of fibres in the mixture increases. It is 0.689 W·m-1·K-1 for simple compressed clay bricks and 0.510 W·m-1·K-1 for a dosage at 3% of thatch fibres. In a bit to validate the results of the pilot study of the apparent thermal conductivity, the heat mass capacity of this composite material was achieved through the use of the dehydration method. The relative difference obtained with the results of the volumetric heat capacity carried out with these two methods was good. All results showed that the use of fibres in compressed laterite brick gives a more insulating composite material that respects Civil Engineering Norms.
