Valorization of Beet Pulps Issued from Sugar Extraction in Cementitious Matrices. Effect of Original Pulp State

Beet sugar manufacturing generates considerable flows of co products among which pulps. At the end of the extraction of sugar, they are rich in water and hard to preserve. They generally undergo an over pressing bringing the proportion of dry matter about 30% and then can be thermally dehydrated and granulated. Over pressed pulps, still wet, keeps very well when sheltered from air. Granulated dried pulps occupy little volume and keep well away from moisture. However, the drying consumes significant amounts of energy. Currently, the main outlet of the pulps is animal feed. But, besides the decline in livestock production connected to the new sugar regulation and to energy problems make indispensable, to maintain the turnover of beet farmhouses, to find new applications to beet pulps. Different ways have been explored. The advantage of a valorization in the form of aggregates in cementitious matrix materials is the use of the co product in its entirety and the improving of the bio based character of construction. However, because energy problems, it was useful to determine the best way to introduce the beet pulp in the process. A comparative study was therefore conducted from over pressed pulps and pellets of the same origin. It appears, at the optimum water content, that mechanical and thermal behavior are little influenced by the original pulp state whatever cement/pulp proportion used. This allows envisaging a valorization of these pulps without going through the stage of thermal dehydration. The results were also compared to those obtained with already marketed ligno cellulosic aggregates. It appears that beet pulps lead to competitive materials

Effect of Substitution of Cement by Mineral Powders on the Physicomechanical Properties and Microstructure of Sand Concretes

The approach that contributes to the development of eco-materials in construction is the use of mineral powders, which can improve mechanical properties and reduce cement consumption. This article aims to study the effect of substitution by mass of cement with mineral powders on the physicomechanical properties and microstructure of sand concretes. The used mineral powders are A: the limestone, B: the natural pozzolan, C: the hydraulic lime, D: (1/3 limestone + 1/3 natural pozzolan + 1/3 hydraulic lime), and E: (1/2 natural pozzolan + 1/2 hydraulic lime). The studied percentages are 5%, 10% and 15%, in both separated and combined states. The studied properties are workability, compressive strength, the elasticity modulus in compression, shrinkage and microstructure analysis. The objective is to target the optimal percentage of the substitution of cement with mineral powders, which ensures the best compromise between the main properties of the studied sand concretes. The obtained results show that the optimal percentage is in favor of the substitution of cement by 10% D (1/3 limestone, 1/3 natural pozzolan and 1/3 hydraulic lime). Even the 15% of mineral powder D, presented similar performances compared to the sand concrete (without mineral powders). Finally, in the context of the development of eco-materials, it should be noted that the 10% D and 15% D (1/3 limestone, 1/3 natural pozzolan and 1/3 hydraulic lime) contribute to decrease the use of cement and consequently to reduce of CO2 emissions

The effect of the treatment process on the mechanical characteristics of cement-date palm fiber composite

The use of lignocellulosic residues in the composite materials manufacture, based on hydraulic binder, as fiber, has shown to improve the mechanical behaviour of the material, preserve the environment and develop a growing need for degradable plant products exploitation. Moreover, this may certainly offer alternative traditional materials. The aim of the present work is to characterize a cement palm date fibre composite to be used in the manufacture of new structural materials and isolation. The study focuses on the fiber dimensional stability which is sensitive to water. The presence of organic matter has been proved to be detrimental to the durability of untreated fiber-reinforced composite. The fibers were treated with boiling water to extract organic matter and then coated with several kind of product. The heat treatment associated with the cement coating in particular, has led to considerable improvement in the fiber water sensitivity and the mechanical behaviour of composite ductility. © 2009 Praise Worthy Prize S.r.l. - All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Effect of wall orientation of the sand concrete lightened by wood shavings on the time lag and the decrement factor

The development of new lightweight concrete based on the valorization of local materials and waste in construction is an environmental and sustainable approach. In this context, the studied composite is a sand concrete (dune and alluvial) lightened by wood shavings to improve its thermophysical properties. The objective is to investigate the orientation effect of an outside wall made with this material in an arid environment on the thermophysical properties of the wall, namely the time lag (Φ) and the decrement factor (f). The experimental study has been dedicated, first of all, to determine the optimal composition of sand concrete lightened by wood shavings, which the content is 60 kg/m3. This composition is a compromise between studied compactness and workability. Then, to study the thermal properties of the sand concrete without wood shavings (SC-W-WS) and sand concrete lightened by wood shavings (SC-WS). Finally, a numerical simulation using the EnergyPlus software was made to study the wall orientation effect designed in the Laghouat city (south of Algeria). The results obtained show that the substitution of sand by wood shavings has improved thermal properties of the wood sand concrete namely: the thermal conductivity, the specific heat and the thermal diffusivity. The simulation results are very interesting, because all orientations are right for the sand concrete lightened by wood shavings (SC-WS). Nevertheless, the north and the west orientations are wrong in the case of the sand concrete (SC-W-WS). However, the east orientation has the longest time lag, which is consistent with the literature. The advantage of these results is in favour of concrete having improved thermophysical properties

Absorption de l’eau et son effet sur la durabilité des bétons de sable allégés par ajout de copeaux de bois

L’objectif principal de ce travail est d’étudier l’effet de l’eau sur les bétons de sable léger à base de matériaux et de déchets locaux. Les matériaux utilisés sont un sable de dune et un sable d’oued et les déchets sont des fillers calcaires (déchets de concassage) et des copeaux de bois (déchets de la menuiserie) [1, 2]. En général, on a remarqué que dans le cas de copeaux de bois non traités, plus le taux de bois est élevé, plus l’absorption d’eau est importante, que ce soit par immersion ou par capillarité. En soumettant le matériau à une série de cycles “mouillage – séchage” accélérés, une légère diminution dans la résistance à la compression a été enregistrée. Par ailleurs, le traitement des copeaux de bois avant leur utilisation [3] a considérablement amélioré la résistance vis à vis de ces cycles “mouillage-séchage”. De même, l’absorption d’eau, par immersion et par capillarité, a été considérablement diminuée. Il convient de noter enfin, que ces résultats viennent confirmer la possibilité d’utilisation de ce matériau montrée par les résultats encourageants trouvés dans les travaux précédents, telles que les propriétés mécaniques et thermiques

Effect of wall orientation of the sand concrete lightened by wood shavings on the time lag and the decrement factor

The development of new lightweight concrete based on the valorization of local materials and waste in construction is an environmental and sustainable approach. In this context, the studied composite is a sand concrete (dune and alluvial) lightened by wood shavings to improve its thermophysical properties. The objective is to investigate the orientation effect of an outside wall made with this material in an arid environment on the thermophysical properties of the wall, namely the time lag (Φ) and the decrement factor (f). The experimental study has been dedicated, first of all, to determine the optimal composition of sand concrete lightened by wood shavings, which the content is 60 kg/m3. This composition is a compromise between studied compactness and workability. Then, to study the thermal properties of the sand concrete without wood shavings (SC-W-WS) and sand concrete lightened by wood shavings (SC-WS). Finally, a numerical simulation using the EnergyPlus software was made to study the wall orientation effect designed in the Laghouat city (south of Algeria). The results obtained show that the substitution of sand by wood shavings has improved thermal properties of the wood sand concrete namely: the thermal conductivity, the specific heat and the thermal diffusivity. The simulation results are very interesting, because all orientations are right for the sand concrete lightened by wood shavings (SC-WS). Nevertheless, the north and the west orientations are wrong in the case of the sand concrete (SC-W-WS). However, the east orientation has the longest time lag, which is consistent with the literature. The advantage of these results is in favour of concrete having improved thermophysical properties

Valorisation de fines minérales industrielles

The fillers resulting from a large number of aggregates quarries, from mining exploitation or from stone industries are not really used at the present time. New technologies have been developed to recycle this waste by making building units. This study deals with the weight-reduction possibilities of cement-fillers mixtures. The authors present a synthesis of an experimental study about fillers of several rocks different by their grading analysis and mineralogical nature. The mechanical and thermal properties are compared with the ones of usual materials like plaster and Autoclaved Aerated Concrete.Les fines résultant d'un grand nombre de carrières de granulats, d'exploitation de minerais ou de l'industrie de la pierre ne sont pas exploitées actuellement et leur stockage présente souvent une gêne. De nouvelles techniques ont été développées par les auteurs pour recycler ces déchets sous forme d'éléments de construction. Cette étude concerne les possibilités d'allégement de mélanges fines-ciment. Après avoir exposé les méthodes utilisées, les auteurs présentent une synthèse d'une étude expérimentale concernant les fines de plusieurs roches différentes par leur granulométrie et leur nature minéralogique. Les propriétés mécaniques et thermiques sont comparées à celles de matériaux usuels tels que le plâtre et le Béton Cellulaire Autoclavé