Study On The Mechanical Behavior Of Foam Filled Concrete Under Penetration Loading

Foamed concrete has been widely used in civil engineering as one of the thermal insulation materials. At present, due to its low density and strength, good cushioning and energy-absorbing performance, and designable strength, foamed concrete begin to be used for Engineering Material of Arresting System(EMAS) as arresting materials, so as to stop the accidental runway aircraft effectively, thereby to reduce the damage caused by the runaway aircraft. In this application, foamed concrete is subjected to the rolling impact of aircraft wheels. However, due to the existence of a large number of voids in foamed concrete, the foamed concrete is likely to absorb water and become aged under natural environment, therefore cannot meet the requirements of durability. Foam-Filled Concrete(FFC) is a kind of new concrete with the polystyrene granules(EPS) bubbles as lightweight aggregate that is added into the cement mortar. The FFC is expected to solve the problem of poor durability of EMAS. In this paper, the mechanical properties of FFC under static and impact penetration loading are studied by carrying out static and impact tests with cylinder flat head and scaled wheel. The results of this paper give a theoretical basis for the application of FFC in EMAS. The specific studies are as follows:(1)Study the dimension and magnitude of physical quantities in aircraft arresting process, such as the characteristic dimension, the characteristic time, the characteristic quality, the characteristic density, the characteristic strength and so on. By use the method of dimension analysis and the law of conservation of energy, the arresting process of Aircraft by EMAS is analyzed, The relevant physical quantities that affected the stopping distance are determined, and the model for predicting the stopping distance of different types of aircrafts are established.(2) Study the mechanical behaviors and the energy absorption performance of FFC under quasi static penetration loading with the cylinder flat head and the scaled wheel. The quasi static penetration behaviors of FFC are investigated by using a cylindrical flat head penetration test, the relationship between failure load and the bubble volume fraction, the shear strength of the material and the uniaxial compressive yield stress is analyzed. The failure load of FFC under quasi-static penetration loading with cylinder flat head is predicted. Two different size scaled wheels are adopted to carry out the quasi static penetration tests, influence of wheel size, bubble volume fraction on the penetration mechanics behaviors of FFC are investigated. And the wheel penetration load is predicted by use the dimensional analysis method.(3) Study the mechanical behaviors and the energy absorption performance of FFC under impact penetration loading with the cylinder flat head and the scaled wheel. Drop hammer impact tests with cylinder flat head and scaled wheel are carried out to investigate the influence of bubble volume fraction and impact velocity on the penetration curves and the energy absorption performance. The energy absorption performance under penetration impact with the cylinder flat head and the scaled wheel are analyzed by used of dimensional analysis. The prediction equation is derived to predict the penetration impact curve.