Experimental Study On The Mechanical Properties Of Rubber Concrete And Its Application In Anti-collision Of Bridge Piers

With the rapid development of transportation infrastructure in China, there has been an explosion in the number of overpass and flyover bridges, which results in frequent accidents of vehicle-bridge pier collision. With the characteristics of good toughness, impact resistance and energy dissipation capacity, rubber concrete is considered as an ideal material for the anti-collision and vibration reduction in bridge pier, which can not only decrease the impact force and accelerate the vibration energy dissipation in pier, but also provide an environment friendly way for the disposal of waste tires in China.In this paper, the basic mechanical properties and the hysteretic energy dissipation performance under the same compressive stress level were studied experimentally. Through analyzing the influence of different volumes and particle sizes on the properties of rubber concrete materials and the related test phenomena, an optimal proportion of rubber concrete material for the anti-collision protective layer on the bridge pier was selected. Pendulum impact tests were conducted on model bridge piers with different anti-collision protective layers. By analyzing the peak value and attenuation law of the impact forces and the dynamic responses of the tested model piers, the effects of different anti-collision protective layers were obtained. The main research results are as follows:(1)With the increase of volume fraction of rubber particles, the difference in the performance between rubber concrete mixture and common concrete mixture gets bigger and bigger and the plastic characteristic of rubber concrete under compression becomes more obvious, meanwhile, the cube compressive strength, axial compressive strength and static compressive elastic modulus decrease. Under the same stress level, the loss factor of rubber concrete increases, indicating that the energy dissipation capacity is enhanced. With the same volume fraction of rubber particles, the loss factor increases with the increase of the loading force amplitude level.(2)With the increase of rubber particle size, the flowability of rubber concrete mixture is significantly enhanced, the cube compressive strength and axial compressive strength decrease while the static compressive elastic modulus increases first and then decreases. The influence of the change in rubber particle size on the mechanical properties of rubber concrete is far less than the change in rubber particle volume fraction.(3)For the pier subjected to horizontal impact, the peak value of impact force, the dynamic response and the vibration attenuation period are in positively correlation with the impact velocity, while the latter two are negatively correlated with the rigidity of the pier itself.(4)The peak values of the impact force and the dynamic response of the pier with rubber concrete anti-collision protective layer are smaller than that of the pier without anti-collision protective layer or with common concrete anti-collision protective layer, and the thicker the rubber concrete anti-collision protective layer is, the smaller the peak values of the impact force and the dynamic response of the pier are. Low rigidity and strong energy absorption capability of rubber concrete material make the impact force of the pier with rubber concrete anti-collision protective layer decreases. And the decrease of the peak value of the dynamic response of the pier is mainly caused by the decrease of the impact force. Due to the high energy dissipation capacity of rubber concrete, the vibration attenuation rate of the pier with rubber concrete anti-collision protective layer is faster than that of the pier with common concrete anti-collision protective layer, and the thicker the rubber concrete anti-collision protective layer is, the faster the vibration rate of the pier decays.