Structural Characterization of Hybrid Fiber Reinforced Polymer (FRP)-Autoclave Aerated Concrete (AAC) Panels

Abstract

The structural characterization of hybrid fiber reinforced polymer (FRP)-autoclaved aerated concrete (AAC) panels is examined in this study. The structural system is based on the concept of a sandwich construction with strong and stiff FRP composite skins bonded to an inner AAC panel. The FRP composite material is made of carbon reinforcing fabrics embedded in an epoxy resin matrix. The carbon fiber reinforced polymer (CFRP) reinforcement is applied on the top and bottom faces of the AAC panel, and several innovative processing techniques are used including the hand lay-up as well as the vacuum assisted resin transfer molding (VARTM). The main focus of the research is to combine the AAC with the FRP face sheets into a synergetic system, which would be consistent with the 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. The CFRP has been used with regular concrete before and has shown phenomenal reinforcing capabilities. The AAC, on the other hand, is a cellular concrete and is very light to work with, in comparison to normal concrete. It is also structurally very brittle in nature and has much lower flexural as well as compressive strengths than normal weight concrete. An experimental protocol based on a four point bending test is used to characterize the stiffness, ductility, and strength response of the hybrid FRP-AAC sandwich panels. Since there are no previous research data available on the hybrid CFRP-AAC panels and the bonding characteristics of AAC with FRP are unknown, a set of basic tests are also initiated including the bonding test on AAC samples wrapped with CFRP. To understand and optimize the flexural/shear behavior of the hybrid CFRP-AAC sandwich panels, several innovative reinforcing schemes with CFRP skin are used, as elaborated in this article. In addition, both continuous and discrete AAC blocks are used to fabricate AAC panels. Results from the experiments emphasize the need for a complementary test program where the best reinforcing scheme from the study would be duplicated in future tests on structural elements of the typical sizes including beams, floors, lintels, etc.