Evaluation of refined cement-based matrix systems for extrusion of wood fiber cement

Different cementitious matrix formulations incorporating various chemical, polymeric and mineral additives were evaluated for use in extruded fiber cement products. These alternative formulations were designed to enhance the end product performance characteristics under aging conditions and to facilitate the extrusion process. The impact of different matrix formulations on mechanical, durability and physical characteristics of extruded cellulose fiber cement products were compared. Test results show that most of the additives lowered the bulk specific gravity but increased the moisture absorption capacity of extruded fiber cement products when compared with the basic mix formulation. Generally, the additives caused drop in flexural strength but did not significantly affect the flexural toughness of the matrix formulations. Upon saturation the frictional pull-out of swollen fibers increased the ductility (deformation) capacity of extruded cellulose fiber cement products. These results provide further insight into performance characteristics of extruded cellulose fiber cement products, and help with selection of matrix mix formulations to meet performance requirements of a particular application.