Abstract
Ultraviolet (UV) irradiation and a combination of UV irradiation and ozone treatment of polyolefin fibers were investigated for possible improvement of mechanical properties in concrete composites. In both treatment methods, various fiber exposure durations were used, and surface modification was monitored by measuring the water contact angle. Untreated and treated fibers were added to concrete at 0.32 % by volume, and the specimens were tested for flexural strength according to ASTM International specifications. Fiber surface treatment by UV alone was found to be an unattractive technique based on the results of flexural tests and contact angle measurements. Ten minutes of UV and ozone surface treatment of fibers was found to improve the composite peak stress by 11 % and the toughness by 4 %; longer periods of exposure led to lower flexural strength results, perhaps as a result of fiber deformation or degradation.