This study evaluates the feasibility of using plant-based polyurethane derived from castor oil as an elastomer in civil engineering structures, such as bridges, viaducts and precast structures, aiming to replace traditional materials like neoprene and steel bearings. The research focuses on assessing mechanical and durability properties of castor oil-based polyurethane, synthesized through mixing prepolymer (A) and a polyol (castor oil) (B), aligning with sustainable construction practices. Mechanical properties, such as Young’s modulus and shear modulus, were investigated through laboratory tests of three different component mixes of A and B, 1:1,5, 1:2,0 and 1:2,5, in mass. Additionally, tests were conducted with neoprene for direct comparison. The experimental results were compared to recognized standards, including ASTM, Eurocode, and Brazilian Standards (NBR). Ultimately, the study will determine whether this material can meet the demands and performance criteria for including load-bearing capacity and deformation tolerance set by the same codes. The results are promising, suggesting the potential for this material to be used in various structural applications.