Experimental investigation on chemical and thermomechanical properties of concrete incorporating Washingtonia Robusta fibers

This work aims to provide new composite material for thermal insulating building applications. The composite was made with mortar reinforced with natural fibers that were extracted from petiole of WR palm tree. The used fibers were first chemically characterized by EDS, SEM, X-ray and infrared diffractometry spectroscopies as well as tensile test to know their morphological structure. Afterward, the fibers were incorporated into mortar with different mass percentages varying from 0 to 4% to experimentally determine the thermomechanical properties of the manufactured samples. The chemical findings indicated that the WR fibers are rich in cellulose, hemicellulose, and lignin, and possess high crystallinity index; which enhance the mechanical properties and durability of the composite. Furthermore, the obtained density of the composite W2RC4% is of 1305 kg/m³ and less than 2000 kg/m³; this composite can be then classified as lightweight concretes according to the standard NF EN 206+A2/CN (2022). The thermal conductivity and thermal effusivity dropped by about 60% and 42% respectively. Moreover, the WR reduces the compressive strength (76%) and the flexural strength (36%) to minimum values respectively of 5.9 MPa and 3.8 MPa. These values meet the mechanical requirements of lightweight concretes (>3.5 MPa).