Experimental Research And Numerical Simulation On Mechanical Behavior Of Autoclaved Aerated Concrete Panel

With the implementation of policy for energy conservation and newly-emerging housing industrialization, energy-efficiency building and fabricated structure were catching more and more attention of the engineers. At present, the traditional way of heat preservation system was considered to be the composite board of cladding panels and polystyrene board, which not only greatly consumed raw building materials(cement, sand and gravel), but also easily lead to quality accidents. Therefore, to reverse the situation by designing novel heat preservation system was of vital significance. Previous studies had merely focused on the physical properties and basic mechanical properties of autoclaved aerated concrete. However, research on the highrise buildings’ cladding panels under wind load and horizontal seismic action was far from enough and satisfactory. On the basis of the experiment and numerical simulation, the basic mechanical behavior of autoclaved aerated concrete as cladding panels was deeply studied.To accurately study the fundamental mechanical properties of AAC panels, forty-five specimens were conducted to analyze the cube compressive strength, the prism compressive strength and the splitting tensile strength. The results showed that the compressive strength parallel to the direction of the gas was equal to 70%~81% of the one perpendicular to the direction of the gas. End-effect had little impact on AAC specimens. The conversion coefficient of prism strength and cube strength was 0.884. The size of autoclaved aerated concrete had affected the cube compressive strength to some extent. The ratio of non-standard specimens’ compressive strength and standard’ one was 0.953. The tensile strength of AAC and compressive strength of AAC had a good correlation. The conversion coefficient was 10.5%.To evaluate the bending behavior and failure mechanism of reinforced autoclaved aerated concrete slabs, Four-point loading test on forty-two specimens were carried out concerning span, reinforcing fabric and types of AAC slabs. The results showed that the failure pattern of AAC slabs could be defined as the bending-shear failure. There existed the bond-slip phenomenon under large force, suggesting that autoclaved aerated concrete and reinforcing bar did not work well together. Provided that the reinforcement area stayed the same, AAC specimens with more bars performed better on cracking load and cracks’ formation. Based on specifications, a series of formulas were conducted to predict the shear capacity and cracking load of AAC slabs and the theoretical value had the strong safety reserve when compared with experimental value.To investigate the ductility, cracking load and ultimate bearing capacity of autoclaved aerated concrete roof panels, the bending experiments of six AAC panels were conducted. The results indicated that the failure pattern of AAC roof panels could be defined as the bendingshear failure. The load-carrying capacity of AAC panels were much lower than the normal one and the ductility was pretty well. A quality accident was taken for example and the paper focused on the cause of roof panel’s damage. Results showed that autoclaved aerated concrete roof panels occurred shear failure because of random overloading, hence leading to large deformation. Besides, the corrosion of reinforcement was caused by the loss of protective layer.The traditional connection joint easily lead to the damge of AAC panels as well as thermal bridge. In order to study the mechanical behavior of cladding panels’ joints under wind load, the joint strength test of twenty AAC panels were conducted to analyze the effects of back-up plate and the area of reinforcement. The results showed that with the increase of back-up plate’s radius and area of reinforcement, the tensile strength of the hook bolt was on the increase. Newtype built-in fitting joint performed better on stiffness and bearing capacity than traditional one.In order to study the nonlinear properties of autoclaved aerated concrete by FEM software ABAQUS, the numerical simulation of four specimens were conducted as well as making comparison with experimental results. The results indicated that the finite element results agreed well with experimental results, suggesting that the concrete damage plasticity model and material constitutive relationship could be used to accurately simulate the properties of AAC.