ANALYSIS OF INFLUENCE OF PROCESSED POLYETHYLENE TEREPHTHALATE (PET) PLASTIC ON ASPHALT PERFORMANCE GRADE PARAMETERS
Asphalt pavement is a common type of pavement used in Indonesia. Asphalt, as the main component of pavement, exhibits viscoelastic properties that influence its rheological characteristics, particularly stiffness and thermal resistance, which are crucial to bear the traffic load and temperature resi...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/80478 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Asphalt pavement is a common type of pavement used in Indonesia. Asphalt, as the main component of pavement, exhibits viscoelastic properties that influence its rheological characteristics, particularly stiffness and thermal resistance, which are crucial to bear the traffic load and temperature resilience. To enhance asphalt performance, one approach involves adding polymers as asphalt modifiers. Cu"ently, several polymer additives derived from processed polyethylene terephthalate (PET) plastic waste, such as newtlac, are available and have shown the potential to improve asphalt performance. PET modification falls under the category of polymer plastomer modification, generally increasing asphalt stiffness to enhance resistance to permanent deformation.
This study focuses on comparing the characteristics of PEN 60/70 oil asphalt with PET-plastic modified asphalt (newtlac) at varying concentrations of 3%, 5%, and 7% by weight. The research aims to investigate the influence of processed PET waste addition on PEN 60/70 asphalt which commonly used in Indonesia. Asphalt performance evaluation involves basic rheological tests (conventional asphalt tests) and mechanistic tests using a Dynamic Shear Rheome/er (DSR). DSR testing includes temperature sweep for Performance Grade (PG) specification and time sweep to examine rutting resistance, fatigue, and response to loading time and temperature. Time sweep results are analyzed using master curves and black diagrams to understand the viscoelastic properties of asphalt with PET modification.
With an increase in complex shear modulus, the mixture stiffness modulus (Smix) also rises with PET concentration, calculated theoretically using the Al-Khateeb equation. Conventional asphalt testing indicates that PET-modified asphalt exhibits increased hardness compared to PEN 60/70 asphalt as PET concentration rises. Additionally, there is an improvement in temperature resistance or a decrease in temperature sensitivity, evident through consistent increases in penetration index (Pl) values, from -1.12 to -0.633 at 7% PET concentration. However, in DSR mechanistic tests, the addition of up to 7% PET modification does not increase asphalt PG values, remaining at PG 64 and an intermediate temperature of 25°C. Nevertheless, there is an observed increase in rutting resistance (G*/sin o) and a decrease in fatigue resistance (G*.sino) within PG parameter values. Time sweep DSR testing reveals consistent increases in complex modulus and a decrease in phase angle with rising PET concentration based on master and black diagram analyses. DSR testing results show an increase in complex shear modulus with increasing PET additive concentration, ultimately enhancing the mixture stiffness modulus (Smix). Based on theoretical Smix calculations, there is a 6.17% increase in deformation service life (Nd) at 3% PET concentration, rising to a 9.42% increase at 7%. However, fatigue service life (N.i) experiences a decrease of 2.78% at 3% PET concentration, reaching a 3.04% decrease at 7%.
In summary, basic rheological testing demonstrates that PET addition enhances asphalt hardness and temperature resistance, as indicated by the increase in the penetration index (Pl) values. In mechanistic rheological testing, PET addition increases the Complex Shear Modulus (G*) and decreases the phase angle ('5) with rising PET concentration. Furthermore, the addition of PET - newtlac increases resistance to rutting but experiences a decrease in fatigue resistance. However, as the NJ value results in a Cumulative Equivalent Single Axle Load (CESA) well above the Nd value, it can be concluded that the addition of PET - newtlac extends the service life with increasing PET concentrations. Further testing on rutting and fatigue is recommended to fully understand the influence of PET - newtlac on asphalt and aggregate mixtures.
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