Management of agricultural biomass wastes:Preliminary study on characterization and valorisation in clay matrix bricks

Abstract

In this work the feasibility of using woody agricultural biomass wastes as grapes and cherrie sseeds,saw- dust,as pore forming agent,and sugar cane ash,as silica precursor,in bricks,were reported. Sawdust and grapes and cherries seeds,thanks to their organic substances content,during their com- bustion,bring an energetic support in the bricks firingphase and act as pore formi ng agent.Usually the addition of this kind of waste is limited to 10 wt.%in order to reach an equilibrium between positive (weightand shrinkage decrease and porosity increase)and negative (increase of water absorption and mechanical resistance decrease)effects.The results show that grapes and cherries seeds,added in aper- centage of 5wt.%to abrick formulation,have better influencewith respect to the sawdust,maintaining the mechanical properties of the firedbrick (950C),showing modulu sof rupture around 21–23MPa with aweight reduction of 3–10%(respectto the standard one).Regarding the sugar cane ash,the addi- tion of 5wt.%improves the mechanical properties (modulusof rupture around 27 MPa)and no weight decrease is observed.These results confirmedthe role played by this kind of agricultural waste,which thanks to its high silica content (61wt.%)is capable to demonstrate afillerand plasticity reducing effect on the brick bodies.Tests carried out highlighted that the addition of these by-products (5wt.%)do not change negatively the main technological properties measured (waterabsorption,linear shrinkage,flex-ural resistance,etc.)and permit to hypothesize their use to obtain bricks with both insulating and higher mechanical properties using apore agent forming or silica carrier alternative raw materials,respectively