Análise do efeito da adição de fibra de polipropileno no comportamento mecânico de uma brita graduada tratada com cimento

Abstract

An experimental technical study was conducted to investigate the effect of the addition of polypropylene fiber on the mechanical behavior of cemented-treated crushed stones (CTCS), in order to evaluate the applicability of this material in layers of pavement. Since the CTCS presents high brittleness and low toughness, subject to an intense micro-cracking process of its internal structure, whether due to the retraction due to hydration of the cement or due to the degradation suffered by the fatigue process, it is imperative to think of reinforcers that minimize this problem by increasing its lifespan. The experimental program initially involved physical characterization tests (shape index, sand equivalent, Los Angeles abrasion, soundness of aggregate, granulometric analysis, relative density and absorption of coarse and fine aggregate) then the standard mixture dosage was determined, and finally the mechanical tests (compressive strength, flexural bending test, flexural modulus and toughness), as well as scanning electron microscope tests. Two polypropylene fiber content (0.62% and 1.24% in volume) were tested and compared to the standard mixture. The fibers used in this study were polypropylene type, monofilament with 60 mm length. All the mixtures were tested at 28 days of curing in the wet chamber, except for the samples used in the toughness tests, in this case with a curing age of 100 days. The results indicated that the flexural mechanical properties can be improved gradually with the addition of fibers, however, they can effectively decrease the compressive strength and flexural modulus. In addition, the fibers cause a reduction in compaction degree in the mixture, especially in the vibratory method.