# Dynamic Response of Reinforced Recycled Aggregate Concrete Pavement under Impact Loading
###### Abstract
The use of recycled waste concretes in construction application and pavement construction is one way to promote sustainable development. Consequently, many researchers have investigated the use of recycled concrete aggregate (RCA) in the production of new concrete, which is named recycled aggregate concrete (RAC). Most findings have indicated that the compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity for RAC decrease with an increase in the content of RCA [12; 13; 14; 15]. Furthermore, some pieces in the literature have studied RAC structural elements, such as columns, beams, slabs, and pavements; the results show that the incorporation of RAC has negative effects on the performance of these elements [16; 17; 18; 19; 20; 21]. In general, the desired reduction caused by using RAC is limited, and further engineering research is encouraged, since satisfactory performance can still be achieved. Dynamic response of reinforced concrete structural elements under impact loading has been investigated through experiments by many researchers [22; 23; 24; 25; 26; 27; 28; 29]. [PERSON] et al. [23; 24] investigated the effects of different types of slab reinforcements and impact energy on the dynamic response and behavior of reinforced concrete slabs. The addition of steel reinforcement provided substantial strength enhancement to the slab, promoted crack formation on the top surface, and increased the stresses and strains that the concrete and steel materials could safely undergo, especially under higher impact energy. [PERSON] et al. [25] conducted an experiment to investigate the effect of steel reinforcement distribution on the dynamic response of high strength concrete (HSC) plates, taking into account the effects of the main bottom steel reinforcement ratio (1.0, 2.0, and 3.0%) and the steel reinforcement arrangement (single or doubly reinforced plates). The results showed that the change of reinforcement ratio and/or reinforcement arrangement has no significant effect on impulse and absorbed energy values for same impact loading condition, while the impact duration decreased with the increase in reinforcement ratio. The reinforcement arrangement could affect the crack pattern; the HSC plates with single reinforcement typically failed by localized sudden punching, and the HSC plates doubly reinforced typically failed in a ductile punching mode. [PERSON] et al. [26] studied the effects of loading rates on the performance of reinforced concrete (RC) slabs. From test results, the damage process, failure mode, strain rate, and energy absorption capacity of RC slabs were similar between the high-loading-rate test and the low-velocity impact test. Therefore, it was suggested that the high load rate test results could be used to analyze the performance of the RC slabs under low-velocity impacts. Both longitudinal and transverse reinforcements were effective in enhancing the maximum strength of specimens. However, the damage to the slab under both high-rate and impact loadings can be more efficiently reduced by adding shear stirrups. In another experimental program [27], five 1200 mm square RC slabs were tested with different nose shapes, diameters of impacted area, drop weights and drop heights in another experimental program; the punching shear failure mode was observed for all the specimens that failed during the test. The damage to the slabs increased with the increase in impact energy, and more impact energy was required to fail RC slabs when the diameter of the impacted area increased. In order to better understand the effects of supporting conditions on the behavior of RC slabs subjected to impact load, some research has been undertaken. [PERSON] et al. [28] found that the number of drops until failure was lower for the specimens with four hinge supports than those for the specimens with four fixed supports, but higher than those for the specimens with two opposite hinge supports.