Blast Resistance of Double-Layered Reinforced Concrete Slabs Composed of Precast Thin Plates

Abstract

When designing blast-resistant reinforced concrete (RC) structures, reducing spall damage due to reflected tensile stress waves is a major problem. Furthermore, for rapid construction of the blast-resistant structures against sudden terrorist bomb attacks, it is necessary to build it with precast concrete walls and reduce the weight of the precast elements by reducing their size for ease of transportation and construction. In this study, to propose an idea for rapid construction and better blast resistance of blast-resistant RC structures, double-layered RC slabs composed of precast thin plates, 50 mm thick, were fabricated and utilized for contact detonation tests. The tests were conducted under a condition that the amount of explosives and the dimensions of specimen were constant respectively, and two types of concrete, normal concrete and polyethylene fiber reinforced concrete (PEFRC), were employed as the slab materials. Our results showed that creating an air cavity between the two layers of PEFRC slab was effective in reducing spall damage, while the air space had no advantage in normal RC, under a condition that the thickness of the air space was fixed at 15 mm. Furthermore, the above difference between PEFRC and normal RC slabs was discussed, based on the numerical result on the fracture process of the air-sandwiched normal RC slab.

Reinforced concrete and fiber reinforced concrete panels subjected to blast detonations and post-blast static tests

“…Research has been carried out to improve the blast resistance of new and existing reinforced concrete (RC) structures. The following techniques have been proposed for improving the blast resistance of RC or unreinforced masonry slabs or walls: (a) strengthening with fiber reinforced polymer composites [2][3][4][5][6][7] or steel plates [8]; (b) employing fiber reinforced concrete as the slab material [8][9][10][11][12][13]; (c) use of a sprayed-on polymer [14]; and (d) use of double-layered precast thin plates made of concrete or polyethylene fiber reinforced concrete with an air cavity between the two layers [15]. A state-of-the art review of research on the blast resistance of FRP or polymer strengthened RC and concrete masonry structures has been presented [2]; it was noted that there is a lack of in-depth research in understanding the fundamental behavior of FRP strengthened structures under blast loading; in addition, it was recommended that further research should be carried out on methods to determine static post-blast load resistance.…”