| Popis: |
This research compares the performance of different fiber types, fiber blends, and welded-wire fabric (WWF) in their ability to prevent and control drying-shrinkage cracking. Restrained shrinkage ring tests were conducted on fiber-reinforced concrete mixtures to determine the age of the first visible crack and maximum crack width. Results for various steel and polypropylene fibers in diverse fiber volumes and shapes are compared with plain concrete and concrete reinforced with WWF. The WWF is not effective in prolonging the age of a first crack but does reduce the maximum crack width. Effectiveness of steel and polypropylene fibers in reducing crack width and increasing the age of first cracking depends on the type of fiber. Commonly used parameters such as volume of fibers, number of fibers, and aspect ratio did not uniquely explain the effectiveness of the fibers. A novel model that equally accounts for influences of all constituents of a composite on its properties is used and extended to describe the shrinkage cracking behavior of the tested materials. |
