Preliminary Research on Tensile Properties of Vulcanized EPDM-Rubber Joint for Application in Inflatable Rubber Dam

EPDM (Ethylene Propylene Diene Monomer) rubber is widely used in structural applications such as inflatable rubber dams, where joint regions are prone to failure under tensile loads. This study evaluates the effect of overlap length on the tensile behavior and failure morphology of EPDM joints bonded using a commercial vulcanized adhesive. Four overlap lengths (0.5, 1, 2, and 3 cm) were tested to assess their influence on joint strength and deformation characteristics. The results show that increasing the overlap length improves load transfer, enhances stress distribution, and increases energy absorption up to a critical value. The 2 cm overlap yielded the highest tensile strength (21.5 MPa) and peak stress (22 MPa), with failure occurring within the rubber substrate, indicating effective stress transfer. Although the 3 cm overlap produced a slightly lower UTS, it demonstrated greater deformation and the highest energy dissipation, consistent with strain-softening behavior in the elastomer. Fracture analysis confirmed that longer overlaps facilitated extended necking. Based on these findings, a 2 cm overlap was identified as the optimal configuration to balance strength and toughness in EPDM joints. This provides valuable design guidance for inflatable rubber dams and similar elastomeric applications.