Mechanical Behavior Analysis of the Cement Treated Aggregate Base With Addition of Synthetic Fiber

An experimental study was conducted to investigate the effect of the addition of polypropylene fiber on the mechanical behavior of cement-treated crushed stones. The experimental program involved the following mechanical tests: compressive strength, flexural bending test, flexural modulus, and toughness, in addition to scanning electron microscopy. Two mixes with fiber addition (0.25% and 0.50% by weight of aggregate) were tested and compared to the standard mixture without fiber. The fiber used was polypropylene type with 60 mm length. All mixtures were tested after 28 days of wet curing, except for samples used in the toughness tests, which were cured for 100 days. The mixtures utilized CP-II-E-32 cement (a standard used in Brazil for cements composed of 34% slag), with a content of 5%. The results indicated that fiber insertion hinders the compaction of the mixture. This causes a reduction in the degree of compaction and, consequently, a decrease in unconfined compressive strength. However, fiber inserts resulted in considerable increases in toughness and tensile strength. The interlacing of the fibers in the internal matrix structure promoted an anchorage effect.