Tahsina Islam

Graduation Semester and Year




Document Type


Degree Name

Doctor of Philosophy in Civil Engineering


Civil Engineering

First Advisor

Sahadat Md Hossain

Second Advisor

Warda Ashraf


The ever-increasing volume of traffic and the volatility of daily and seasonal temperatures that are being experienced globally make it essential that the quality and durability of roads are improved. Modifiers can improve the engineering properties of the asphalt mix in these situations. Perhaps plastics are the most promising of all types of modifiers. Since the disposal of plastic waste is a major concern for the environment, recycling of these waste materials is highly desired. The recycling and reuse of plastic waste is a prime example of sustainable waste management. It reduces the buildup of waste in landfills, thereby reducing hazards inherent in landfills, increases the landfills’ active life, and potentially increases the lifespan and reduces the maintenance of roadways. Current study reflects two-fold major objectives (a) To improve the pavement strength; and (b) To reduce the plastic waste. This study provides a critical review of the history and process of reusing plastic waste in asphalt, reviews previous studies that have been conducted on the subject, and assesses the potential reuse of plastic waste in asphalt pavement design today to improve the properties of pavement. Using recycled plastics and recycled asphalt pavement (RAP) materials, this study was carried out to determine if there is a correlation between rutting and cracking. An experimental program was developed to conduct different volumetric and performance tests with different RAP content, plastic types and plastic content. Three types of recycled plastic were utilized – Low density polyethylene (LDPE), High density polyethylene (HDPE) and Polypropylene (PP) mixed with Superpave SP-C mix to test the applicability of these materials for use in flexible pavement surface layers. According to the study, up to 8 percent recycled shredded plastic can be mixed with 15% RAP mixture, whereas increasing the RAP content by 25% reduces the performance of the mix. The value of indirect tensile strength (IDT) and tensile strength ratio (TSR) increases with an increase in plastic content. Moreover, rutting depth decreases significantly (up to 75% reduction) with the increase of plastic content. The plastic modified mix can double the service life of the pavement according to the findings of Overlay test. In pavement design, one of the most important parameters is the rutting depth. However, the rutting test is too time consuming, and the equipment is expensive to conduct regularly. However, indirect tensile strength tests are easier to perform. Hence, in order to determine the value of the rutting depth for different combinations of recycled materials, MLR models were developed using the indirect tensile strength (IDT), RAP content, plastic type and plastic content. This experimental research can be not only a solution to the worldwide waste plastic disposal problem but also can help reducing the depletion of natural resources.


Rutting, Cracking, Modifier, Recycle, Plastic


Civil and Environmental Engineering | Civil Engineering | Engineering


Degree granted by The University of Texas at Arlington