Investigation of basalt fiber composite aging behavior for applications in transportation

New materials such as basalt fiber offer the promise of innovative applications in transportation because of documented strengths (V. Ramakrishnan, N.S. Tolmare, and V. Brik, NCHRP-IDEA Program Project Final Report, Transportation Research Board, Washington, DC, (1998)). Previously, we found that mechanical properties of basalt twill fabric-reinforced polymer composites were comparable to composites reinforced with glass fabrics of similar structures [Q. Liu, M.T. Shaw, R.S. Parnas, and A.M. McDonnell, Polymer Composites, 27(l), 41 (2006)]. Use in transportation also requires knowledge of environmental durability. This study reports the tolerance of basalt-fiber-reinforced polymer composites to salt water immersion, moisture absorption, temperature, and moisture cycling. Parallel tests were conducted for the corresponding glass-reinforced polymer composites. Aging for 240 days in salt water or water decreased the Young's modulus and tensile strength of basalt composites slightly but significantly (a < 0.05). Freeze-thaw cycling up to 199 cycles did not change the shear strength significantly, but aging in hot (40 degrees C) salt water or water did decrease the shear strength of basalt composites (p < 0.05). The aging results indicate that the interfacial region in basalt composites may be more vulnerable to damage than that in glass composites.