The construction industry continues to rely on conventional materials like cement,which often can come with a high cost and significant environmental impact,particularly in terms of greenhouse gas emissions.To tackle ...The construction industry continues to rely on conventional materials like cement,which often can come with a high cost and significant environmental impact,particularly in terms of greenhouse gas emissions.To tackle the challenges of sustainable development,there is growing interest in using local available materials with low environmental impact.This study primarily focuses on synthesizing and characterizing a geopolymer binder made from local materials found in Benin to stabilize CEB(compressed earth brick).The synthesis involves combining amorphous aluminosilicate powder with a highly concentrated alkaline solution.Local calcined kaolinite clay(metakaolin)and corn cob ash obtained after calcination at 600°C were used with a 12 M sodium hydroxide(NaOH)solution.Different mixtures of geopolymer were formulated substituting metakaolin by corn cob ash at rates of 0%,5%,10%,and 15%of the dry weight of the mixture.Thereafter physical and mechanical characterization tests were conducted on each formulation.Results showed that geopolymer binders containing 85%metakaolin and 15%corn cob ash exhibited the best physical and mechanical performance(e.g.12.08 MPa for compression strength).Subsequently,this geopolymer formulation was used to stabilize CEB.Characterization revealed that CEBs stabilized with 10%geopolymer exhibit good mechanical properties(6.93 MPa),comparable to those of CEBs stabilized with 10%cement(7.40 MPa),justifying their use as load-bearing walls in construction.展开更多
The housing sector today uses elaborate materials such as cement,iron,sand,often prohibitively expensive and whose production generates a strong environmental impact(scarcity of resources,transport,greenhouse gas gree...The housing sector today uses elaborate materials such as cement,iron,sand,often prohibitively expensive and whose production generates a strong environmental impact(scarcity of resources,transport,greenhouse gas greenhouse,etc.).In order to meet the challenges of sustainable development,earth construction is experiencing a resurgence of interest these days.Despite its many advantages,raw earth material has drawbacks,in particular its low mechanical resistance and its loss of geometric characteristics in the face of water,which slow down its development.As part of this study,the mechanical characteristics and durability of raw earth were improved by using residual water from the processing of Parkia Biglobosa(nere)and Vitellaria Paradoxa(shea)nuts in order to optimize its use for the construction of modern buildings.To this end,the decoctions resulting from the artisanal transformation of the nut of the Parkia Biglobosa into African mustard and of the Vitellaria Paradoxa into shea butter were added to the raw earth according to volume proportions of 25%,50%,75%and 100%of the aqueous solution to obtain the projected composites.Thus,mechanical characterization and durability tests were carried out on the composites obtained.The results revealed that the decoctions of Vitellaria Paradoxa and Parkia Biglobosa improve the compressive strength of the material by up to 90%and 260%,respectively.Furthermore,these decoctions improved the resistance to water penetration of the 100%additive composite by 1.5 times for Vitellaria Paradoxa and 5 times for Parkia Biglobosa.This study shows that it is possible to use decoctions as raw earth stabilizers to build modern,ecological buildings at lower energy costs.However,more in-depth studies on surface wettability and long-term durability are planned to better characterize the geomaterial.展开更多
This work focused on the search for biobased materials capable of being used in road techniques as soil inclusions, and on studying the influence of their incorporation on the characteristic parameters of pavement lay...This work focused on the search for biobased materials capable of being used in road techniques as soil inclusions, and on studying the influence of their incorporation on the characteristic parameters of pavement layers. To this end, pineapple, cyperus and imperata plant fibers, due to their endemic availability, were used as reinforcement on sourced materials, notably bar soil, lateritic gravel and silty sand. Complete identification and mechanical tests (Proctor and CBR) were carried out on materials in their natural state (soil) and on composite materials (soil + plant fibers) in the laboratory to determine their classification in road geotechnics, their compaction parameters and their mechanical behavior. Firstly, the various types of 2.5 cm long fibers were incorporated into the different types of soil at mass contents of 1% and 2%. This part of the study showed that the pineapple fiber composite incorporated into class A2 bar soil offered the best results, with a 38% gain in CBR index compared with the natural soil. Pineapple fibers incorporated at 1% in lateritic gravel raise the CBR value of the reinforced soil to 10% of the CBR value of the natural soil and to 7% for silty sand.展开更多
Poor wastewater management coupled with lack of sanitation facilities has aggravated the sanitation challenges in developing countries.?This study was aimed at providing information on the current state of sanitation ...Poor wastewater management coupled with lack of sanitation facilities has aggravated the sanitation challenges in developing countries.?This study was aimed at providing information on the current state of sanitation in Cotonou City through surveys. The most common sanitation facilities in the city were septic tanks, latrines and soakaway pits. Mechanical desulging was mainly used (94%) for desludging latrines and septic tanks with a frequency of less than once a year for 73% of the houses;manual desludging was most common for soakaway pits. 84% of sullage generated is disposed without treatment. The only existing stabilization pond plant, managed by a private company SIBEAU, is overloaded;the effluent is poor (up to 2250mg/l BOD5) and does not meet any quality standards. 96% of survey respondents recognise that the sanitation situation in the city is not good;it has to be improved by providing an appropriate and sustainable sanitation management system.展开更多
基金support received for this work from the UNSTIM Competitive Funds,2023 edition of the University of Science,Technology,Engineering,and Mathematics(UNSTIM).
文摘The construction industry continues to rely on conventional materials like cement,which often can come with a high cost and significant environmental impact,particularly in terms of greenhouse gas emissions.To tackle the challenges of sustainable development,there is growing interest in using local available materials with low environmental impact.This study primarily focuses on synthesizing and characterizing a geopolymer binder made from local materials found in Benin to stabilize CEB(compressed earth brick).The synthesis involves combining amorphous aluminosilicate powder with a highly concentrated alkaline solution.Local calcined kaolinite clay(metakaolin)and corn cob ash obtained after calcination at 600°C were used with a 12 M sodium hydroxide(NaOH)solution.Different mixtures of geopolymer were formulated substituting metakaolin by corn cob ash at rates of 0%,5%,10%,and 15%of the dry weight of the mixture.Thereafter physical and mechanical characterization tests were conducted on each formulation.Results showed that geopolymer binders containing 85%metakaolin and 15%corn cob ash exhibited the best physical and mechanical performance(e.g.12.08 MPa for compression strength).Subsequently,this geopolymer formulation was used to stabilize CEB.Characterization revealed that CEBs stabilized with 10%geopolymer exhibit good mechanical properties(6.93 MPa),comparable to those of CEBs stabilized with 10%cement(7.40 MPa),justifying their use as load-bearing walls in construction.
基金supported by the Beninese state.An author received a trainer training grant from the Benin state for stays in the Jean Lamour Institute Laboratory of the University of Lorraine in France to carry out tests.
文摘The housing sector today uses elaborate materials such as cement,iron,sand,often prohibitively expensive and whose production generates a strong environmental impact(scarcity of resources,transport,greenhouse gas greenhouse,etc.).In order to meet the challenges of sustainable development,earth construction is experiencing a resurgence of interest these days.Despite its many advantages,raw earth material has drawbacks,in particular its low mechanical resistance and its loss of geometric characteristics in the face of water,which slow down its development.As part of this study,the mechanical characteristics and durability of raw earth were improved by using residual water from the processing of Parkia Biglobosa(nere)and Vitellaria Paradoxa(shea)nuts in order to optimize its use for the construction of modern buildings.To this end,the decoctions resulting from the artisanal transformation of the nut of the Parkia Biglobosa into African mustard and of the Vitellaria Paradoxa into shea butter were added to the raw earth according to volume proportions of 25%,50%,75%and 100%of the aqueous solution to obtain the projected composites.Thus,mechanical characterization and durability tests were carried out on the composites obtained.The results revealed that the decoctions of Vitellaria Paradoxa and Parkia Biglobosa improve the compressive strength of the material by up to 90%and 260%,respectively.Furthermore,these decoctions improved the resistance to water penetration of the 100%additive composite by 1.5 times for Vitellaria Paradoxa and 5 times for Parkia Biglobosa.This study shows that it is possible to use decoctions as raw earth stabilizers to build modern,ecological buildings at lower energy costs.However,more in-depth studies on surface wettability and long-term durability are planned to better characterize the geomaterial.
文摘This work focused on the search for biobased materials capable of being used in road techniques as soil inclusions, and on studying the influence of their incorporation on the characteristic parameters of pavement layers. To this end, pineapple, cyperus and imperata plant fibers, due to their endemic availability, were used as reinforcement on sourced materials, notably bar soil, lateritic gravel and silty sand. Complete identification and mechanical tests (Proctor and CBR) were carried out on materials in their natural state (soil) and on composite materials (soil + plant fibers) in the laboratory to determine their classification in road geotechnics, their compaction parameters and their mechanical behavior. Firstly, the various types of 2.5 cm long fibers were incorporated into the different types of soil at mass contents of 1% and 2%. This part of the study showed that the pineapple fiber composite incorporated into class A2 bar soil offered the best results, with a 38% gain in CBR index compared with the natural soil. Pineapple fibers incorporated at 1% in lateritic gravel raise the CBR value of the reinforced soil to 10% of the CBR value of the natural soil and to 7% for silty sand.
文摘Poor wastewater management coupled with lack of sanitation facilities has aggravated the sanitation challenges in developing countries.?This study was aimed at providing information on the current state of sanitation in Cotonou City through surveys. The most common sanitation facilities in the city were septic tanks, latrines and soakaway pits. Mechanical desulging was mainly used (94%) for desludging latrines and septic tanks with a frequency of less than once a year for 73% of the houses;manual desludging was most common for soakaway pits. 84% of sullage generated is disposed without treatment. The only existing stabilization pond plant, managed by a private company SIBEAU, is overloaded;the effluent is poor (up to 2250mg/l BOD5) and does not meet any quality standards. 96% of survey respondents recognise that the sanitation situation in the city is not good;it has to be improved by providing an appropriate and sustainable sanitation management system.
