Abstract
The mechanical properties of asphalt mixtures used in highways construction depend to large extent on the type and quantity of the used asphalt. With time any asphalt pavement can exhibit various distresses that will eventually lead to the pavement failure.
Various types of additives and modifiers have been used in asphalt to mitigate the distresses. Fiber is one of the additives used for this purpose. The principal function of the fiber is to provide additional tensile strength in the resulting composite. This could increase the amount of strain absorbed during the fatigue and fracture process of the mixture.
In local asphalt pavement, the severity of permanent deformation and thermal cracking has been increased due to the increase in track axle loads, tire pressure, and the difference in pavement temperature, therefore, the modified dense graded mixtures with polypropylene fibers suggested for use in highway wearing courses to provide adequate resistance to permanent deformation and to provide additional tensile strength in the resulting composite.
The effects of variation in polypropylene fiber content, asphalt cement content, aggregate gradation and testing temperature are evaluated through the results of Marshall Methodology, indirect tensile strength, indirect creep test, and ultrasonic testing.
The results obtained from this study showed that the PPF improved the mixture’s performance in several unique ways against the anticipated major pavement distresses.
The addition of (0.3%) polypropylene fiber by weight of total mix with type (A) aggregate grading will help in produce more flexible mixtures that are also more resistant to permanent deformation and thermal cracking.
The relationship between the dependent and independent variables was examined by descriptive statistical analysis. The SPSS statistical package was used to perform this analysis.
