Barcelona Test as an Alternative Method to Control and Design Fiber-Reinforced Concrete Pipes

The use of fibers as primary reinforcement for concrete pipes (CPs) is known by both industrial and scientific researchers as an attractive alternative to steel. However, the use of fibers in CPs has not yet been well-established in this industry because of, among other reasons, the lack of systematic quality control of fiber-reinforced concrete pipes (FRCPs). Therefore, an experimental program involving the production and testing of 600 mm (23.6 in.) internal-diameter FRCPs was performed using low contents of steel (10 and 20 kg/m(3) [0.62 and 1.25 lb/ft(3)]) and polypropylene (2.3 and 4.6 kg/m(3) [0.14 and 0.29 lb/ft(3)]) fibers. These FRCPs were expected to be viable alternatives to those unreinforced and steel bar-reinforced concrete pipes corresponding to low- to moderate-strength classes. A numerical simulation of the tests using the constitutive equation derived from the Barcelona test was carried out, aimed at confirming that both can be an innovative combination to deal with both the characterization of the FRC tensile behavior and the direct design of these pipes. In this regard, those pipes containing 20 kg/m(3) (1.25 lb/ft(3)) of steel fibers reached the C60 strength class in the TEBT (equivalent to ASTM C76 Class I). Consequently, the steel bars could be completely replaced by fibers. This fact led to an effective reduction of 20% of steel as well as to the elimination of those operations related to the reinforcement preparation. Simultaneously, these FRCPs represent a challenge at a numerical level because the model could be insensitive to this low amount of fibers. The comparisons between the experimental and numerical results have confirmed the suitability of both the model and the constitutive equation to simulate the pipe response when subjected to the TEBT.