Field testing of blast responses and strengthening methods of reinforced autoclaved aerated concrete panels

Autoclaved aerated concrete (AAC) is a type of lightweight cellular concrete with a homogeneous void or cell structure. Because of its physical characteristics, AAC has many advantages, such as heat insulation, sound insulation, and fire resistance. AAC masonry blocks or reinforced AAC elements are widely used in public and civil buildings. Reinforced AAC panels, also known as autoclaved lightweight concrete panels, are made of AAC and steel reinforcing cages and are commonly used as panels. Explosions due to accidents or warfare have occurred more frequently in recent years, which often threaten the safety of building structures. In order to protect personnel and buildings, it is crucial to understand the dynamic response and damage of the reinforced AAC panels under blast loadings and find effective strengthening methods. In this study, 12 TNT blast tests were carried out on reinforced AAC panels, considering two strength classes of AAC and different strengthening materials. Various scaled distances were considered to investigate the blast resistance performance of reinforced AAC panels. The corresponding displacement responses of reinforced AAC panels were recorded. The damage characteristics and damage modes of the panels were compared and analyzed. The test results show that rein-forced AAC panels have poor blast resistance performance and the damage mode changed as the scaled distances decreased. Increasing the strength of AAC or adding 5 mm strengthening layers significantly reduced the displacement response of reinforced AAC panels. Polyurea-strengthened and engineered geopolymer composites (EGC)-strengthened panels had similar displacement responses at the same scaled distance. Double-layer EGC prevented the fragmentation both on the front and rear faces. EGC strengthening is a very economical approach for reinforced AAC panels.