Compressive behavior of yellow bamboo stalks (Phyllostachys aurea species) and their composites when filled with epoxy resin

This research explores the properties of yellow bamboo (Phyllostachys aurea species) stalks and its composite from Colombia under compression loads. The bamboo pipes were filled with epoxy resin aiming structural applications. Samples included untreated, peroxide-treated, and hypochlorite-treated bamboo, both with and without nodes. For each of these conditions, up to 20 samples were evaluated via Weibull distribution; this is to determine the variability of the compressive properties. For the characterization, scanning electron microscopy was used to analyze the microstructure, while finite element analysis was included for the bamboo stalks to better understanding of the stress–strain relations. Results showed that compressive strength was from 60 to 130 MPa, with nearly 3 times more variability for samples with node than without node, which was accounted for the Weibull modulus. Also, it was seen that bamboo stalks without node showed higher strength than samples with node, in which the node acts as stress concentrator, lowering the strength of the bamboo pipe. For bamboo stalks filled with epoxy resin was found that the resin did not contribute much to reinforce the composite, but increased the elongation at break, a very important property related to ductility and toughness. The resin also was found to increase the Weibull modulus upon the compression loads, which reduced the property variability, a known limitation of natural fiber composites. It was also observed that in both the bamboo stalks and the composites, the failure presents buckling deformation, with cracks along the longitudinal direction, parallel to the pipe axis, although with less damage for those with nodes, since the node can limit the crack growth. The composite bamboo resin could be used in construction or impact applications.