Carbon nanotubes (CNTs) and short-aramid-fiber epoxy (SAFE) toughened adhesive joints between bamboo scrimber and steel substrates treated with resin pre-coating (RPC) method

Abstract

Composite structures made from bamboo scrimbers and other wood or even steel substrates have generated increasing attention in construction industries around the world. This study reports an experimental study on the interfacial bonding properties of strengthened adhesive joint between bamboo scrimber and steel substrates by epoxy adhesive. Some toughening techniques are used to enhance the bonding ability of the joint. Firstly, resin pre-coating (RPC) method is applied resin on the bonding surfaces of bamboo scrimber and steel substrates, for the purpose of preventing debonding failure of the interfacial zone. Then carbon nanotubes (CNTs) and short-aramid-fiber epoxy (SAFE) methods are introduced on the basis of RPC method in order to use CNTs or short Kevlar fibers to further strengthen the joints. Last. SAFE/CNTs method is used which is intended to hybrid the advantages of CNTs and SAFE methods. Single shear test (SLS) is used to measure the bonding properties. The result shows that RPC, CNTs, SAFE and SAFE/CNTs methods have apparent effects to improve the bonding ability of the epoxy adhesive joints, in that the average shear strength of their joints increase 2.25, 2.52, 2.56 and 2.65 times compared to the control group, meanwhile, the average shear energy increase 7.05, 7.41, 9.08 and 9.57 times respectively. Moreover, the reinforced joints generate the structural failure in bamboo scrimber substrate while the control joint only has debonding failure on the steel bonding surface. The key reason is that RPC method using acetone diluted resin (without hardener) could penetrate deep into the sub-surface zone of bamboo scrimber, uniting CNTs and SAFE technique, it changes the interfacial zone of the joint into a strong entirety.