Utility of polyparaphenylene terephtalamide fiber in hot mix asphalt as a fiber

• In this study, utility of PT as fiber in HMA is researched.
• The optimum bitumen content is determined as 4.65% by Marshall Stability test.
• Samples with different bitumen contents, and different fiber rates was produced.
• Optimum stability is obtained from 4.65% bitumen content and 0.25% fiber rate.

In this study, utility of polyparaphenylene terephtalamide (PT) was investigated in hot mix asphalt as a fiber. For this aim samples were prepared with limestone aggregate at different proportions. Marshall Stability test was applied and optimum bitumen content was determined. In the second stage of the study, new samples were prepared using different polyparaphenylene terephtalamide fiber (PTF) rates of 0.25%, 0.50%, 0.75%, 1.00%, 1.50%, 2.00% based on optimum bitumen content. When examining test results, samples which prepared using 0.25% PTF rate gave highest Marshall Stability result. At the final stage of the study, different bitumen contents (4.15%, 4.65% and 5.15%) were conducted for the best fiber rate (0.25%) and close to this result (0.50% and 0.75%). Thus, the effect of bitumen content on determined fiber rate at the second stage of the study was investigated. Also Indirect Tensile (IDT) Strength Test was performed on hot mix asphalt (HMA) samples preparing at 0.25%, 0.50% and 0.75% fiber rates and moisture sensitivities were determined. All results showed that, the best fiber rate was 0.25% and determined optimum bitumen content remain constant with the fiber additive for the reference samples. Besides, some sample groups which prepared using different PTF rates proved the specification limits and it was said that; PTF can be used in asphalt concrete as a fiber additive.

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