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Increasingly high quantities of waste plastics cause major environmental problems in Benin due both to the non-biodegradability of such by-products of the petroleum industry and to a lack of appropriate means of treatment. An option to valorise waste plastic bags is to use these in construction processes. This article studies the incorporation of waste plastic bags into cement-mortar with the aim of reducing proliferation. It explores the immediate consequences of cement-mortar-plastic combinations, such as changes in the resultant composite’s water absorption ratio and mechanical properties. The process of making the composite includes some main steps, during which waste plastic bags are first melted at 200°C-250°C and then mixed with sand aggregates. These coated aggregates are then mixed with cement and water into mortar. Moulded specimens of derived composites are then submitted to hydrothermal ripening and mechanical analysis. Experimental results allow optimizing the sand-aggregates coating process, providing data to locate the most appropriate ratio of plastic bags to be between 8% and 12% (wt/wt.mix):theoretically10.07%. The adopted practical value was 10%, leading to cement-plastic-mortar compositeswith90%reduction of water absorption ratio and 11.60% decrease in absolute density, compared to uncoated sand composites. Similarly, the mechanical strengths of composites were 8.83±0.34MPa in compression and 4.1±0.82MPa in 3-points flexural bending, corresponding to 74.1% and 48.1% weakening, respectively. These resistances were judged to be weak, with the result that the composites thus obtained cannot be used as the main elements of structural constructions. Potential applications are water-sealing/repellent materials in walls/soil, ending with good values of a wear-resistance index similar to commercial quarry tiles/stoneware.Keywords: Waste plastic bags, cement-plastic-mortar composite, aggregates coating, ripening, water-absorption ratio, wear-resistance index

La pyrolyse semble être un procédé adapté au traitement des déchets à base de carton. Afin d’optimiser les conditions expérimentales du procédé de pyrolyse et d’apporter des éléments pour le dimensionnement d’une installation, une étude du comportement thermique du carton est indispensable. Dans le présent document, l’étude de la dégradation thermique d’échantillons de carton en conditions de pyrolyse a été réalisée par analyse thermogravimétrique. Des essais en régime isotherme sous atmosphère inerte (sous argon) à différentes températures 250, 280, 300 et 320°C ont été réalisés. Ces isothermes ont été choisies après détermination de la plage de température de dégradation du carton en utilisant l’ATG en régime dynamique. Un modèle cinétique en deux phases de pyrolyse a été utilisé pour déterminer les paramètres cinétiques : l’énergie d’activation, le facteur pré-exponentiel de la pyrolyse du carton ondulé dans les conditions isothermes.Mots clés : Analyse Thermogravimétrique, Carton, Cinétique, Energie d’Activation

International audience; We performed experiments using starch and its derivatives for impregnation coupled with thermal treatment and a new drying process called the Successive Pressure Drops Dehydration (DDS). This treatment aims to stabilise the archaeological waterlogged woods originated from different museums in France, Italy and Spain. Over all anti-shrink efficiency, (ASE) values in range of 77 to 94% were achieved. We chose to use the corresponding normal measured shrinks which values lay between 4,19 and 8,8 %. The resulting appearance, based on the colour analysis and the splits checking of the treated samples, was aesthetically pleasing. The scanning electronic microscopy and the determination of the dry matter gain showed that the starch and its derivatives penetrated and partially bulked the degraded woods. The experimental results showed that the devised process, starch impregnation plus thermal treatment and DDS, was a suitable treatment method for the conservation of the waterlogged wooden artefacts.