Evaluation of Mechanical Properties of Reinforced Poplar Laminated Veneer Lumber

Abstract

Three types of reinforcement materials, a carbon fiber-reinforced polymer (CFRP) sheet, a glass fiber-reinforced polymer (GFRP) mesh, and a composite of the CFRP sheet and GFRP mesh, were used to reinforce poplar laminated veneer lumber (LVL), and the multi-step hot-pressing method was also applied. The mechanical properties, i.e., modulus of rupture (MOR), modulus of elasticity (MOE), and horizontal shear strength (HSS), of the reinforced LVL were investigated, as well as the effects of lay-up location of the CFRP sheet/GFRP mesh composite. The results indicated that applying the multi-step hot-pressing method and incorporating the CFRP sheet, GFRP mesh, and the CFRP sheet/GFRP mesh composite noticeably improved the MOR and MOE under horizontal and vertical loadings. Only the multi-step hot-pressing method was able to greatly improve the HSS of reinforced LVL under both loading modes. The improved effect of the three kinds of reinforcing materials on the mechanical properties was ordered as follows: CFRP sheet/GFRP mesh composite > CFRP sheet > GFRP mesh. Locating the CFRP sheet/GFRP mesh composite closer to the surface veneer layer yielded the best mechanical properties for the reinforced poplar LVL.