Currently, in a context of sustainable development, the economic and environmental challenges incite, to valorize local materials such as clays and agro-industrial waste. It is in this approach that a new category of ...Currently, in a context of sustainable development, the economic and environmental challenges incite, to valorize local materials such as clays and agro-industrial waste. It is in this approach that a new category of compressed earth bricks (BTC) stabilized with shea meal (TK) and cement was proposed. The purpose of this paper is to investigate the effect of shea meal rate on the thermal conductivity properties of cement stabilized earth bricks. A lateritic clay (Lat) mainly composed of kaolinite (38.44%), quartz (24.94%), goethite (12.28%), hematite (4.44%) and illite (19.9%) was used to make bricks. Different mix designs made up of lateritic clay and 5% cement were studied. The shea meal is added as a partial lateritic clay replacement in different proportions. The thermal conductivity was determined by hot disk method and correlated to both porosity and density of elaborated materials. The results obtained show that the thermal conductivity and density of bricks decrease respectively from 0.72 W·m-1·K-1 to 0.52 W·m-1·K-1 and from 2.77 g·cm-3 to 2.52 g·cm-3. The presence of shea meal within the material generates pore formation, which may partly explain the improvement of the thermal insulation properties. A positive correlation was noted between density and thermal conductivity of these materials.展开更多
The structural and thermomechanical properties of starch-based plastic films reinforced with kaolin and metakaolin have been studied by various techniques (X-ray diffraction, IR-TF spectroscopy, scanning electron micr...The structural and thermomechanical properties of starch-based plastic films reinforced with kaolin and metakaolin have been studied by various techniques (X-ray diffraction, IR-TF spectroscopy, scanning electron microscopy, tensile tests, and thermal resistance). The results obtained showed that kaolin, an inert material, prevents the starch from losing its granular structure and to solubilize during the heating, generating plastic films of low Young’s modulus (7 MPa). On the other hand, metakaolin, an amorphous and dehydroxylated material obtained after heating of kaolin at 700°C for 1 hour, substantially improves the thermomechanical properties of the plastic films. The Young’s modulus increases from 19 MPa to 25 MPa while the thermal resistance increases from 90°C to 120°C. This was attributed to good dispersion of the metakaolin in the polymer matrix after the loss of the granular structure of the starch during heating.展开更多
Clay materials of the quarry of Bingerville (district of Abidjan) have been characterized by chemical analysis, X-rays diffraction, infrared spectroscopy and thermal analysis. These materials contain kaolinite (41% - ...Clay materials of the quarry of Bingerville (district of Abidjan) have been characterized by chemical analysis, X-rays diffraction, infrared spectroscopy and thermal analysis. These materials contain kaolinite (41% - 84%), illite (4% - 10%), quartz (14% - 27%), goethite (2% - 5%) and small amount of rutile (1%) that are not toxic minerals. They also contain some heavy metals which are beneficial to human biological activity (cobalt, copper, molybdenum, zinc) in tiny quantities. Some other heavy metals (lead, cadmium) which are considered as poisonous for human are present in very low content. The samples characterized by relatively fine grains are moderately crystallized. Their specific surface area varied from 26 to 43 m2·g—1. The mineralogical and physicochemical characteristics of these samples are like ones known for their healing properties. The consumption by internal way of studied materials, although it may be beneficial, requires a sifting to remove coarse grains (Φ > 2 μm) and a previous microbiological control.展开更多
文摘Currently, in a context of sustainable development, the economic and environmental challenges incite, to valorize local materials such as clays and agro-industrial waste. It is in this approach that a new category of compressed earth bricks (BTC) stabilized with shea meal (TK) and cement was proposed. The purpose of this paper is to investigate the effect of shea meal rate on the thermal conductivity properties of cement stabilized earth bricks. A lateritic clay (Lat) mainly composed of kaolinite (38.44%), quartz (24.94%), goethite (12.28%), hematite (4.44%) and illite (19.9%) was used to make bricks. Different mix designs made up of lateritic clay and 5% cement were studied. The shea meal is added as a partial lateritic clay replacement in different proportions. The thermal conductivity was determined by hot disk method and correlated to both porosity and density of elaborated materials. The results obtained show that the thermal conductivity and density of bricks decrease respectively from 0.72 W·m-1·K-1 to 0.52 W·m-1·K-1 and from 2.77 g·cm-3 to 2.52 g·cm-3. The presence of shea meal within the material generates pore formation, which may partly explain the improvement of the thermal insulation properties. A positive correlation was noted between density and thermal conductivity of these materials.
文摘The structural and thermomechanical properties of starch-based plastic films reinforced with kaolin and metakaolin have been studied by various techniques (X-ray diffraction, IR-TF spectroscopy, scanning electron microscopy, tensile tests, and thermal resistance). The results obtained showed that kaolin, an inert material, prevents the starch from losing its granular structure and to solubilize during the heating, generating plastic films of low Young’s modulus (7 MPa). On the other hand, metakaolin, an amorphous and dehydroxylated material obtained after heating of kaolin at 700°C for 1 hour, substantially improves the thermomechanical properties of the plastic films. The Young’s modulus increases from 19 MPa to 25 MPa while the thermal resistance increases from 90°C to 120°C. This was attributed to good dispersion of the metakaolin in the polymer matrix after the loss of the granular structure of the starch during heating.
文摘Clay materials of the quarry of Bingerville (district of Abidjan) have been characterized by chemical analysis, X-rays diffraction, infrared spectroscopy and thermal analysis. These materials contain kaolinite (41% - 84%), illite (4% - 10%), quartz (14% - 27%), goethite (2% - 5%) and small amount of rutile (1%) that are not toxic minerals. They also contain some heavy metals which are beneficial to human biological activity (cobalt, copper, molybdenum, zinc) in tiny quantities. Some other heavy metals (lead, cadmium) which are considered as poisonous for human are present in very low content. The samples characterized by relatively fine grains are moderately crystallized. Their specific surface area varied from 26 to 43 m2·g—1. The mineralogical and physicochemical characteristics of these samples are like ones known for their healing properties. The consumption by internal way of studied materials, although it may be beneficial, requires a sifting to remove coarse grains (Φ > 2 μm) and a previous microbiological control.
