MECHANICAL PERFORMANCE OF DUCTILE CEMENT MORTAR COMPOSITES REINFORCED WITH NANOFIBRILLATED CELLULOSE

Most of the published works on the field of natural fibre reinforced cement mortar composites, describe the use of natural fibres with several mm in length (2-10 mm) and diameters ranging between 10-30 mu m such as wood pulps, sisal and abaca fibres, cotton linters, etc. It is well-known that the reinforcing capability of these fibres can be increased by reducing their size into the nanometre scale. Although the application of nanofibres in polymer composites is widespread, as far as we know, there is a lack of data related to the use of these fibres as reinforcements in cement mortar matrices. In this work, the performance of ductile cement mortar composites reintbrced with cellulose nanofibres has been evaluated and compared with the one of composites reinforced with conventional sisal pulp. To improve the composite degradation, silica fume was replaced partially the portland cement. In addition, the effect of a decrease of sand particles in the performance of the material has been analyzed. Results show how the use of nanofibrillated cellulose fibres combined with fine sand leads to composites with enhanced both flexural modulus and flexural strength. Nevertheless, the higher values of fracture energy were obtained for the composites prepared with conventional pulps.