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