Flexural Reinforcement of Autoclaved Aerated Concrete (AAC) with externally bonded Carbon Fiber-Reinforced Polymer (FRP) Sheet

Abstract

The flexural behavior of hybrid fiber-reinforced polymer (FRP) - Autoclaved Aerated Concrete (AAC) panels is examined. The structural system is based on the concept of sandwich construction with strong and stiff FRP composite skins bonded to an inner AAC panel. The FRP composite material was made of carbon reinforcing fabrics embedded in an epoxy resin matrix. The carbon fiber reinforced polymer (CFRP) reinforcement was applied on the top and bottom faces of the AAC panel and several innovative processing techniques were used including hand lay up as well as VARTM (Vacuum Assisted Resin Transfer Molding). The main focus of the research is to combine AAC with FRP face sheets into a synergetic system which would be consistent with recent interest in high performance and zero maintenance of civil infrastructures. This combination being lightweight in nature has the potential to be used for speedy panelized construction purposes, for disaster mitigation and to prevent labor intensive construction. CFRP has been used with regular concrete before and has shown phenomenal reinforcing capabilities. AAC on the other hand is a cellular concrete and it is very light to work with in comparison to the normal concrete. It is also structurally very brittle in nature and has much lower flexural as well as compressive strengths than the normal weight concrete. An experimental protocol based on a four point bending test is used to characterize the stiffness, ductility and strength response of hybrid FRP-AAC sandwich panels. Experimental results showed a significant influence of the FRP, because the AAC beams demonstrated an increase in ultimate flexural capacity and stiffness. A numerical modeling was conducted to predict the strength of FRP-AAC element and theoretical results found in good accordance with the experimental results for tested elements.