Chapter 11, Problem 11.15QP

Three 6 in. × 12 in. concrete cylinders with randomly oriented steel fiber contents of 0, 2, and 3% by weight, respectively. After curing for 28 days, the specimens were subjected to increments of compressive loads until failure. The load versus deformation results were as shown in Table P11.15.

Assuming that the gauge length is the whole specimen height, determine the following:

a. The compressive stresses and strains for each specimen at each load increment.

b. Plot stresses versus strains for all specimens on one graph.

c. The modulus of elasticity for each specimen.

d. The ultimate strength for each specimen.

e. The strain at failure for each specimen.

f. Toughness. Curves may be approximated with a series of straight lines.

g. Comment on the effects of increasing the fiber content on the following:

i. Modulus of elasticity

ii. Ultimate strength

iii. Ductility

iv. Toughness