Laboratory Investigation of Modified Roller Compacted Concrete Pavement (RCCP) Containing Macro Synthetic Fibers

This experimental study examines the impacts of two macro synthetic fiber additives (i.e., polypropylene and polyolefin) on laboratory characteristics of roller compacted concrete pavement (RCCP). The mixtures were made at different dosages of 2.0, 3.0, and 4.0 kg/m(3). The compressive, splitting tensile, and flexural strengths of RCCP mixtures were determined at 7, 14, and 28 days. Evidently, the test results disclosed adding 2.0 and 3.0 kg/m(3) fiber additives could improve the compressive strength of modified specimens although adding 4.0 kg/m(3) lowered the compressive strength. In the meantime, the tensile and flexural strengths of RCCP mixtures were considerably improved due to fiber additives, especially at later ages. It is worth mentioning that specimens with polypropylene fiber could manifest higher tensile and flexural strengths compared to polyolefin fiber and any further increase up to 4.0 kg/m(3) fiber additives reduced the strength of mixtures over time. Regardless of the fiber type, the toughness of mixtures containing 3.0 kg/m(3) fibers outperformed plain concrete for enduring flexural loads. Noteworthy, the Vebe test outcomes revealed that adding synthetic fibers could increase the Vebe time significantly. Finally, the relationships between the splitting tensile strength, flexural strength, and compressive strength were obtained as f(r )= 0.60vf(c)', and f(t )= 0.41vf(c)', respectively.