Structural Synthetic Fibers for Three-Dimensional Reinforcement of Concrete

The strength, toughness properties and plastic shrinkage potential of the structural synthetic fiber reinforced concrete are evaluated in this paper. The test results indicated that there was a significant increase in the flexural strength and a slight increase in the first crack strength as the fiber content was increased from 0.5 to 2.0% by volume. The Japanese toughness factors and equivalent flexural strengths were also significantly increased as the fiber content increased. There was also a tremendous increase in impact strength with an increase in fiber content. Very high average residual strengths (ARS) (ASTM C 1399) were obtained and the ARS values increased as the fiber content increased. The contribution of structural synthetic fibers to plastic shrinkage reduction of concrete was studied using cement-rich concrete and the experimental results are reported in this paper. The fiber dosages used were 0.5, 1.0, and 2.0% by volume of concrete. The tests were conducted using 51 mm (2.0 in.) thick slab that was 1 m (3 ft) long and 0.6 m (2 ft) wide. The crack development was enhanced by using fans that can produce a wind velocity of 22 km/h (13.2 m/h). The performance of these fibers was compared using the crack areas of control slab with no fibers and fiber reinforced slabs. The results indicate that structural synthetic fibers at the dosages used, tremendously reduced the plastic shrinkage in concrete. The crack area reduction varied from 100 to 92% of the plain concrete. There was absolutely no cracking when a fiber dosage of 2.0% by volume of concrete was used.