Weibull modulus from size effect of high-performance fiber-reinforced concrete under compression and flexure

Abstract

The Weibull modulus, a material parameter describing the size effect of brittle material, of high-performance fiber-reinforced concretes (HPFRCs) was investigated under compression and flexure. The compressive specimens were as follows: 70.7 × 70.7 × 70.7 mm (cube), 100 × 100 × 100 mm (cube), 150 × 150 × 150 mm (cube), Ø100 × 200 mm (cylinder), Ø150 × 300 mm (cylinder). The bending specimens were as follows: 40 × 40 × 120 mm, 100 × 100 × 300 mm and 150 × 150 × 450 mm. For each size or shape, two HPFRCs having different fiber content were examined as follows: HPFRC1 having no fiber and HPFRC2 containing 1.0% macro hooked fibers blended with 0.5% micro smooth fibers by volume. There was a clear size effect on the compressive and bending parameters for both the investigated HPFRCs. The derived Weibull modulus of the investigated HPFRCs for the mechanical parameters varied from 1.33 to 8.74. Furthermore, the correlation between the bending and compressive strengths of the two HPFRCs and their conversion factors for various sizes and shapes of the compressive specimens were explored.