Experimental Study on Compressive Damage Characteristics of Rubber Concrete Based on Acoustic Emission Technology

Rubber concrete， as an environmentally innovative material， combines waste rubber recycling with performance enhancement of concrete， making its damage mechanism a critical research focus. This study investigates the dynamic compressive damage process of rubber concrete using acoustic emission （AE） technology， with variables including rubber content， particle size， and loading modes. The results indicate that the damage progression is divided into four stages： compaction of initial defects， stable crack propagation until penetration， macroscopic crack expansion accompanied by bulging， and compressive failure. In the early and middle stages， increasing rubber content elevates the frequency of high-energy AE events， while reducing rubber particle size initially increases and subsequently decreases such events. During the final stage， high-energy AE events decline across all variable conditions. Cyclic loading tests confirm the presence of the Kaiser effect in rubber concrete， defining its effective stress range： the lower limit can be neglected， while the upper limit follows trends consistent with compressive strength variations under different variables. The physical mechanisms underlying the Kaiser effect in rubber concrete are elucidated.