Geotechnical and mechanical tests conducted on lateritic gravels of Burkina Faso showed that this material presents: fines (10.5
wt.%), plasticity index (10.5%), Californian Bearing Ratio (43%), ...compressive strength (1.26
MPa) and tensile strength (Brazilian test) of 0.09
MPa. The X-ray diffraction (XRD) and the chemical analysis revealed a quartz amount of 42
wt.%, 26
wt.% of kaolinite, 15
wt.% of goethite, 6
wt.% of rankinite and 3
wt.% of hematite. The results of geotechnical and mechanical tests combined to those of the XRD and the chemical analysis particularly the silica/sesquioxides ratio showed that the lateritic gravels is suitable for the sub-base course in road construction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Local clay from Burkina Faso has been used as a basic raw material in the formulation of ceramic tile with a natural talc (0 - 4% wt) as a flux. The used sintering temperatures are between 950 and ...1100 °C with one hour as hold at heating rate of 5 °C∙min-1. The different technological properties (shrinkage, water absorption and mechanical strength) are improved when the sintering temperature exceeds 1000 °C. The mixture with 4% wt of talc provides better properties than the other grades. The tiles obtained at 1050 °C with 4% wt of talc have similar characteristics to those obtained at 1100 °C without talc. An energy gain with a difference of temperature of 50 °C could be made with the use of talc as the adjuvant.
The influence of MgO on mechanical and microstructural properties of raw clay material from Burkina Faso was investigated by means of an X-ray diffraction, scanning electron microscopy, infrared ...spectroscopy, differential thermal analysis and numerical simulation. The mineralogical composition was modified with the formation of new crystalline phases such as mullite, spinel -- Mg, enstatite and forsterite. During the sintering and with add of MgO, the mullite quantity decrease contrary to forsterite and affect the different properties of sintered products. The mechanical properties were improved with MgO amount around 2 -- 5 wt%. For magnesia amount higher than 5 wt%, the magnesia is not entirely consumed and is originated to the formation of pores in the manufactured products which are detrimental to the mechanical properties.
Microstructural changes of adobe bricks made of lime-clayey raw material mixes were investigated by X-ray diffraction, infrared spectrometry, differential thermal analyses, scanning electron ...microscopy and energy dispersive spectrometry. The impact of these changes on the mechanical resistance and water absorption of adobe bricks was evaluated. It is found that lime additions resulted in the development of calcite and poorly crystallized calcium silicate hydrate (CSH). The latter compound is mainly originated from the reaction between fine filiform quartz and lime. The contribution of the pozzolanic reaction, involving kaolinite (the unique clayey constituent of the raw material), to CSH formation seems to be insignificant. The development of CSH together with the formation of minor amounts of calcite, in <10
wt.% lime samples, improved the mechanical strength and the compactness of adobe bricks. However, the quasi-absence of CSH and the excessive contents of portlandite (Ca(OH)
2) and calcite, observed for >10
wt.% lime, had a slight detrimental effect on the measured physical properties. In all cases, lime amended adobe bricks are suitable for rural building construction in tropical countries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Microstructure of cement-lateritic gravels mixes, containing up to 8
wt% cement, was investigated by means of X-ray diffraction, infrared spectrometry, differential thermal analysis, scanning ...electron microscopy and energy dispersive spectrometry. Also, strength characteristics of the mixtures were measured. The results show that cement admixtures resulted in the formation of 1.4
nm-tobermorite, ettringite, iron oxyhydroxide, portlandite and calcite. The increasing amount of tobermorite, due to the increase of the cement content, was attended with a noticeable reduction of particles segregation. In addition, its marked crystallization, observed for the high curing time (28 days), contributed to the improvement of the mechanical strength. As regards the application aspect, the results show that cement amended lateritic gravels are convenient for base course construction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► Highlight the effects of quicklime on microstructural, geotechnical and mechanical characteristics of lateritic gravels. ► The CSH formed provided the pozzolanic reaction between a part of ...kaolinite and hydrated quicklime. ► Appreciable improvement of mechanical properties was obtained with CSH formation for quicklime amount ⩽3
wt.%. ► The obtained mixes are convenient for base course in road construction.
Microstructure of quicklime-lateritic gravels mixes, containing up to 8
wt.% quicklime, was investigated by using X-ray diffraction, infrared spectrometry, differential thermal analysis, scanning electron microscopy and energy dispersive spectrometry. Geotechnical and mechanical properties of the mixtures were also measured. Quicklime additions resulted of reduction of clayey fraction, plasticity index, methylene blue value and maximum dry density and the increasing of optimum moisture content. The results showed also that quicklime admixtures resulted in the formation of calcium silicate hydrate type I (C–S–H (I)), portlandite and calcite. This CSH (I) was formed through the pozzolanic reaction between a part of the kaolinite and hydrated lime in the basic medium. Moreover, C–S–H (I) marked crystallization with curing time and observed for the quicklime amounts (⩽3
wt.%), contributed to the improvement of mechanical properties. These lime modified lateritic gravels are convenient for base course in road geotechnical applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
La recherche de produits de construction non énergivores, résistants et moins coûteux est de nos jour une préoccupation mondiale du fait des ressources (énergétiques, financières,…) limitées. Dans ce ...travail, nous avons associé la décoction de gousses de Parkiabiglobosa (Néré) riche en tanins, notamment en acide gallique, épicatéchine et épigallocatéchine gallate, à un mélange argile–sable afin de répondre à cette problématique. L’argile utilisée est référencée KORO et contient de la montmorillonite, de l’illite, du quartz, de l’albite, de l’orthose, de la kaolinite et de la goethite. L’étude des propriétés mécaniques des géomatériaux formulés à partir du mélange montre qu’ils présentent des valeurs de résistances mécaniques plus élevées et que leur comportement devient viscoplastique. Cela est dû à la formation de complexes chimiques entre les atomes de fer des oxy-hydroxydes dans l’espace interfoliaire des minéraux argileux et les radicaux carboxyliques des macromolécules de tanins. Ce processus est accentué par la sorption des tanins à la surface des minéraux de l’argile.
Researches for non-energy intensive construction products, that are durable and cheaper is today of global concern because of the limited resources (energy, financial, etc.). To address this issue, the present work presents the combination of the decoction of pods of Parkia Biglobosa (néré) that is rich in tannins compounds including gallic acid, epicatechin gallate and epigallocatechin, with a clay-sand mixture. The clay used is referenced KORO and contains montmorillonite, illite, quartz, albite, orthoclase, kaolinite and goethite. The study of the mechanical properties of geomaterials formulated from the mixture shows that they have values of mechanical resistance higher and that their behavior becomes viscoplastic. This is due to the formation of chemical complexes from carboxylic groups of tannins macromolecules with the iron oxy-hydroxide in the interlayer spacing of clay minerals. This process is enhanced by the sorption of tannins on the surface of clay minerals.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Raw materials from Burkina Faso were used in the production of white pastes for stoneware tiles for pavement. The basic material which is kaolin clay (Loulouka) was added with some natural plastic ...clay (Korona), feldspar, talc, sand for the formulations of batches for these tiles. Four batches (S1, S2, S3 and S4) consisting of raw basic clay material, plastic clay, feldspar, talc and sand have been prepared for the elaboration of tiles sintered up to 1,150 °C. The changes during the sintering process of tiles were investigated by means of X-ray diffraction and scanning electron microscopy. Mainly mullite, enstastite and glassy phase were formed during the sintering at 1,150 °C. Also the physical properties (water absorption, linear shrinkage) and flexural strength of the tiles were measured. These above properties were improved notably with increasing temperature because of mainly the formation of mullite and glassy phase which reduces the number of pores and their size. The tiles fired at 1,150 °C obtained with batch consisting of 62 % mass of basic material, 20 % mass of feldspar, 10 % mass of sand, 5 % mass of plastic clay and 3 % mass of talc (S4) belong in Europeans Standards-class BIb.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Researches for non-energy intensive construction products, that are durable and cheaper is today of global concern because of the limited resources (energy, financial, etc.). To address this issue, ...the present work presents the combination of the decoction of pods of Parkia Biglobosa (néré) that is rich in tannins compounds including gallic acid, epicatechin gallate and epigallocatechin, with a clay-sand mixture. The clay used is referenced KORO and contains montmorillonite, illite, quartz, albite, orthoclase, kaolinite and goethite. The study of the mechanical properties of geomaterials formulated from the mixture shows that they have values of mechanical resistance higher and that their behavior becomes viscoplastic. This is due to the formation of chemical complexes from carboxylic groups of tannins macromolecules with the iron oxy-hydroxide in the interlayer spacing of clay minerals. This process is enhanced by the sorption of tannins on the surface of clay minerals.
La recherche de produits de construction non énergivores, résistants et moins coûteux est de nos jour une préoccupation mondiale du fait des ressources (énergétiques, financières,…) limitées. Dans ce travail, nous avons associé la décoction de gousses de Parkiabiglobosa (Néré) riche en tanins, notamment en acide gallique, épicatéchine et épigallocatéchine gallate, à un mélange argile–sable afin de répondre à cette problématique. L’argile utilisée est référencée KORO et contient de la montmorillonite, de l’illite, du quartz, de l’albite, de l’orthose, de la kaolinite et de la goethite. L’étude des propriétés mécaniques des géomatériaux formulés à partir du mélange montre qu’ils présentent des valeurs de résistances mécaniques plus élevées et que leur comportement devient viscoplastique. Cela est dû à la formation de complexes chimiques entre les atomes de fer des oxy-hydroxydes dans l’espace interfoliaire des minéraux argileux et les radicaux carboxyliques des macromolécules de tanins. Ce processus est accentué par la sorption des tanins à la surface des minéraux de l’argile.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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