|
Title |
Effects of Mixing Ratio of Rigid Polyurethane and Size of Preplaced Aggregate on Damping Ratio and Mechanical Properties of Composites
|
|
Authors |
김민형(Minhyeong Kim) ; 박세언(Se-Eon Park) ; 김경민(Kyungmin Kim) ; 김민혁(Minhyuk Kim) ; 이방연(Bang Yeon Lee) |
|
DOI |
https://doi.org/10.11112/jksmi.2026.30.4.10 |
|
Keywords |
감쇠비; 경질 폴리우레탄; 사전 채움 골재; 강도 Damping ratio; Rigid polyurethane; Preplaced aggregate; Strength |
|
Abstract |
This study experimentally investigated the effects of the mixing ratio of two-component rigid polyurethane (RPU) and the maximum size of preplaced coarse aggregates on the damping and mechanical properties of composites. For this purpose, the weight ratio of resin to hardener was varied from 1.00 to 1.75, and a two-stage casting process was employed to manufacture specimens with various maximum coarse aggregate sizes (13 mm, 19 mm, and 25 mm). Subsequently, impact excitation and mechanical strength tests were performed. The experimental results showed that while the compressive strength of the pure RPU mixture (RPU1.00) was 30 % lower than that of the control cement-based mixture (C40), its flexural strength and damping ratio were 14 times and 57 % higher, respectively. Although increasing the resin ratio enhanced the damping ratio up to 11.4 %, the compressive strength significantly dropped to 1.0 MPa, resulting in a loss of load-bearing capacity. In contrast, the composites incorporating preplaced aggregates (RPU1.00-PA series) effectively maintained a compressive strength of approximately 30 MPa and achieved an average flexural strength 5.4 times higher than that of the C40 mixture. Ultimately, the most balanced pure polyurethane mixture (RPU1.00) and the preplaced aggregate composite (RPU1.00-PA25) exhibited normalized performance indices approximately 15 times and 5.6 times higher than that of the control mixture, indicating their potential as candidate materials for high-damping structural applications.
|