The present study aims to reduce the use of cement and encourage the utilization of plant biomass.  The rice husk ash (loading: 2, 6, 10, 15, 25, 30, 35, 40, 45 and 50%) was used as a cement substitute.  The effects of rice husk ash on the physical and mechanical properties of cement matrix composite was investigated. The results of this study show a drop in compressive strength of 19.75 to 5.10 between M0 and MR50 with a remarkable value of 17.02MPa at 10% (MR10). Likewise, we have a variation of the flexural strength from 2.96 to 0.47 between M0 and MR50 with a remarkable value of 1.87 at 10% (MR10). The material MR10 is light and can be used as a filling element.

International audience This work concerns the field of recycling of waste intobuilding materials. It reports on the possibility ofrecovering plastic waste and related products fromthe wood industry, in construction. The objective ofthe study is to give added value to wood-plasticcomposites produced using the cold compressionmolding process, by improving their mechanicalproperties. Through the bending test, the influence oftwo manufacturing parameters - compactionpressure and drying temperature after molding - onthe mechanical properties, was evaluated for the caseof a composite based on tropical wood sawdustcoming from Benin and recycled polystyrene (CBPo).It appears that the compaction pressure and thedrying temperature are essential factors to considerwhen evaluating the mechanical performance of thecomposite. Increasing the compaction pressure to alimit value significantly improves the properties of thematerial. The optimal properties of CBPo wereobtained at a pressure of 7 MPa. Post-forming dryingat 100 ° C also significantly improved the performanceof the composite. In addition, thanks to its enhancednew mechanical properties, the CBPo is repositionedrelatively to other existing materials, thus making itpossible to think about new applications inconstruction. Ce travail concerne le domaine du recyclage dedéchets en matériaux. Il rend compte d’unepossibilité de valorisation de déchets plastiques et deproduits connexes de l’industrie du bois dans laconstruction. L’étude vise à donner une valeurajoutée à un composite bois-plastique élaborésuivant un procédé de moulage par compression àfroid, par l’amélioration de ses propriétésmécaniques. A travers un essai de flexion, l’influencede deux paramètres de fabrication - pression decompactage et température de séchage postmoulage- sur les propriétés mécaniques, a étéévaluée dans le cas d’un composite à base de sciuresde bois tropicaux venant du Bénin et de polystyrène(CBPo) recyclés. Il en ressort que la pression decompactage et la température de séchage, sont deuxfacteurs essentiels à considérer lors de l’évaluationdes performances mécaniques du composite.L’augmentation de la pression de compactage jusqu’àune valeur limite améliore significativement lespropriétés du matériau. Les propriétés optimales duCBPo ont été obtenues à la pression de 7 MPa. Leséchage post-moulage à 100°C, a également amélioréde façon significative les performances du composite.Aussi, par ses nouvelles performances mécaniques, leCBPo se repositionne par rapport à d’autresmatériaux existants permettant ainsi d’en envisagerde nouvelles applications dans la construction.

No abstract

This work is devoted to the study of the fatigue behaviour of a cement matrix composite reinforced by sugar cane bagasse short fibers. The objective is analysis of the fatigue behaviour in order to assess its ability to withstand use on wall structures, in bracing, false ceiling of this material. Some series of tests carried out in compression and flexion characterized the material mechanical properties, the tests in monotonic and cyclic three-point bending showed the material behaviour in use. For the composite, another fairly conventionally used representation is to visualize the variations in material properties as a function of the number of cycles. The Wöhler curves is plotted from the strain stresses and the number of cycles for the end of test criteria. It shows the influence of increase in stress on the material service life face of breaking. The Fatigue limit corresponds to the line s =26.40 MPa, stress for which no breaking is observed after an infinite number of cycles, and the Endurance limit corresponds to the line of stress 26.79 MPa, the limit value towards which the stress amplitude tends when the number of cycles becomes very large.

No abstract