Experimental investigation on flexural behavior of full-scale glued laminated bamboo (glubam)-concrete composite beams: A case study of using recycled concrete aggregates

The use of recycled aggregate concrete (RAC) and engineered bamboo is expected to reduce the environmental impact of the construction industry. This paper presents an experimental study on the flexural behavior of fullscale glubam (glued laminated bamboo)-RAC composite beams using four-point bending tests. Four glubam-RAC composite beams containing 30% recycled concrete aggregates to replace natural coarse aggregates and one plain glubam beam were manufactured and tested to examine the effect of slab width (i.e., 600 mm and 1000 mm) and type of shear connector (i.e., notch-screw and screw) on the structural response of the beam. Test results concerning the failure characteristics, relative interface slip, strain distribution and load-to-displacement curves measured at the mid-span of each beam were discussed. Diagonal concrete cracks at the notch and a horizontal laminated-shear slip located on the bottom of notched glubam were observed in the notch-screw connected composite beams; while screw connected composite beams had a laminated shear slip appeared at the mid-height of the glubam and distributed along the beam length. The analysis of strain distribution shows that the maximum compressive strain of RAC in the composite beams is far less than the compressive strains of plain concrete both at peak stress and failure with respect to its stress?strain relationship. Generally, an increase in RAC slab width (spacing of glubam beams in real structures) leads to a decrease in the load bearing capacity. The ?-method recommended by Eurocode 5-Part 1.1 can provide an acceptable prediction in estimating the flexural strength of glubam-RAC composite beams with small slab width. Composite action analysis demonstrates that the glubam-RAC composite beams manufactured using both notch-screw and screw connectors reveal the flexural characteristics of partial composite beams due to the relative slip occurring at their interface.