Experimental and Numerical Studies of Impact Behavior of Fiber Lightweight Aggregate Concrete

After the 9-11 attack, protection of iconic, strategic and public structures subjected to impact and explosive loadings has been a major topic of research, which also involves with progressive collapse, thermal effects, damage analysis and advanced material technologies. The demand for Light Weight Aggregate Concrete (LWAC) in many recent applications is increasing owing to the fact that lower density of structural material leads to lower gravitational loading of structures and consequently lower earthquake forces. Nevertheless, LWAC usually suffers from low ductility similar to other brittle materials. A remedy is to add fibers to increase the ductility and energy absorption. As these lightweight constructions may be subjected to impact loadings during life time period, investigating the impact behavior of concrete structures is necessary. A few studies were performed on impact behavior of normal fiber reinforced concrete. Nonetheless, there is no report on impact behavior of fiber reinforced lightweight aggregate concrete. In this research, cylindrical fiber lightweight aggregate concrete samples with 150 mm diameter and 60 mm thickness are exposed to low velocity impact load (according to the standard of ACI 544-2R "impact test on fiber reinforced concrete") and compared with plain concrete samples. Coarse pumice aggregates were used in concrete. Also, polypropylene was utilized in mixtures proportion of concrete. In addition to experimental approach, a numerical simulation has been performed to analyze the test specimens under impact loadings using the LS-DYNA finite element software. Comparison of numerical predictions with experimental results illustrates fairly good agreement.