الفهرس | Only 14 pages are availabe for public view |
Abstract Impact load is one of the most dangerous dynamic loads, which can affect structural components, bridges, train roads, roads, and runways of airplanes. Hence, recently, there is an accelerating interest for researchers to understand the behavior of different structural components under impact loading in order to provide design methods that can withstand this load condition. Nowadays many aircraft with different weights and gear configurations are landing on airport runways. It is clear that this difference in airplanes causes different quantities of damage on the rigid and flexible pavements. The main objective of this research is to study the impact resistance and energy absorption properties of reinforced ferrocement concrete slabs reinforced with various types of reinforcing Metallic and nonmetallic meshes, and use them to design airport runways. Ferrocement is a composite material in which the inherent properties of two constituent materials are optimally utilized. The filler material is reinforced with layers of reinforcing mesh in both principal directions. However, the subdivision and distribution of ductile material (wire mesh) throughout the matrix increase its elasticity. For this study, 36 different ferrocement slabs of dimensions 400 mm X 400 mm X 25 mm ,50 mm and reinforced with 1Ø5.5 every 100 mm were cast with alteration in the combinations of mesh layers. Test results were analyzed to find the different crack patterns. The slabs were cast with weld mesh, expanded mesh, and woven mesh with two different thicknesses. The impact load testing has been performed after the slabs have been heated in the oven for 24 hours at a temperature of 50°C and 100 °C. The impact loading was applied to the specimens by dropping a 5 kg steel ball from a height of 1000 mm at the center of the slabs. The impact energy at the initial cracking stage and at failure was determined for all the slabs. The results indicated that higher energy absorption, maximum numbers of blows, and maximum displacement at the last blow is achieved in slabs of a combination of 2 layers of woven mesh (50 mm) at a temperature of 50°C as they are effective in controlling the developed cracks. Experimental results are then compared to analytical models using (ABAQUS/Explicit) programs, it was observed that slabs of a combination of 2 layers of woven mesh (50mm) at a temperature of 50°C had maximum numbers of blows, higher energy absorption, and maximum displacement at last blow. In addition, slabs of a combination of 1 layer of welded mesh(25 mm) at a temperature of 100°C showed lower numbers of blows, energy absorption, and Displacement. The average percentage of the first crack loads of the tested slabs between the experimental results and the numerical results is 5 %, while the average percentage of the ultimate loads of the tested slabs between the experimental results and the numerical results is 5 %. In addition, the average percentage of the maximum displacement of the tested slabs between the experimental results and the numerical results is 5.8 %. Therefore, there is a good agreement between experimental and numerical results. |