Study on mechanical behavior of modified wood chips reinforced cementitious composites and reinforcing mechanism of wood chips from the perspective of energy

Abstract

ABSTRACT In this study, the mechanical behavior of modified wood chips reinforced cementitious composites was tested and compared with the composites prepared by ordinary(untreated) wood chips and the control. The effect of wood chips content was also evaluated. Then the reinforcing mechanism of modified wood chips was discussed through force analysis, contact angle test and surface energy calculation. And the reasons for the change of contact angle and surface energy were explained by FT-IR and SEM. The results showed that the compressive strength of modified wood chips reinforced cementitious composites decreased, whereas the flexural strength, flexural toughness, toughness index, fracture energy, and ductility index increased significantly compared to the control. With the increase in wood chips content, the compressive strength gradually decreased, the flexural strength increased at first and then decreased, and flexural toughness, toughness index, fracture energy, and ductility index gradually increased. Further, all the mechanical properties of modified wood chips reinforced cementitious composites were superior to those of ordinary wood chips reinforced cementitious composites. The reinforcing mechanism of modified wood chips is mainly attributed to the energy storage and dissipation behavior, and the modification improves the interfacial compatibility between the wood chips and cement matrix. Also, the combined modification makes the wood chips hydrophobic.