<![CDATA[Carbon fiber reinforced polymer (CFRP) composites are widely used in structural applications due to their high strength-to-weight ratio; however, their epoxy matrix exhibits relatively poor flame resistance. This study investigates the effect of aluminum trihydroxide (ATH) addition on the tensile strength and burning rate (BR) of twill carbon fiber/epoxy composites. The composites were fabricated using a vacuum bagging method to ensure improved resin impregnation and uniform filler distribution. ATH content was varied at 0%, 5%, 10%, and 15% by weight of resin. Tensile testing was conducted according to ASTM D3039, while BR testing was performed based on ASTM D635. A total of 28 specimens were subjected to tensile testing using a universal testing machine, while 12 specimens were used for BR testing based on ASTM standards. The results show that tensile strength decreases from 482.09 MPa (0% ATH) to 376.30 MPa (15% ATH). This corresponds to a reduction of approximately 21.9%. In contrast, the BR decreases from 2.86 mm/s to 1.65 mm/s, indicating an improvement in flame resistance of approximately 42.3%. The addition of ATH improves fire resistance through endothermic decomposition and water vapor release, which reduces heat and slows flame propagation. However, it negatively affects mechanical performance due to particle agglomeration and weakened interfacial bonding. Considering the balance between tensile strength and flame resistance, the 10% ATH composition may provide the most balanced composite performance in this study. This study highlights a trade-off between mechanical properties and fire resistance in composite materials.]]>
