Di samping merealisasikan dan melaksanakan pendekatan yang mampan untuk pembinaan turapan asfalt, pemilihan bahan yang tepat juga adalah penting dan boleh menjadi tugas yang mencabar. Ketahanan turapan asfalt merangkumi pelbagai aspek yang boleh dikaitkan dengan tindak balas mekanikal bahan, interaksi antara lapisan struktur, dan pengaruh mekanisme yang tidak berkaitan dengan beban seperti kesan pengoksidaan, kelembapan dan keadaan cuaca yang teruk. Objektif kajian ini adalah untuk mengenal pasti dan memahami kesan pengusiaan terhadap prestasi Campuran Asphalt Panas Bergred Jurang (GGAM) dan pada pelbagai keadaan kelembapan. Untuk menilai prestasi campuran dari segi keretakan lesu dan potensi kecacatan kekal, Ujikaji telah dibahagikan kepada dua fasa. Di dalam fasa pertama, kesan CaCO3 dengan OPC atau TPOFA sebagai bahan tambahan terhadap sifat reologi pengikat bergred penusukan 60/70 pada suhu tinggi dan pertengahan diukur menggunakan meter likat berputar Brookfield dan reometer ricih dinamik. Kemudian, spesimen disediakan menggunakan agregat kasar berbentuk kubik, pengikat bergred penusukan 60/70 dan bahan pengisi iaitu kalsium karbonat (CaCO3) sebanyak 6%, dengan 2% adalah daripada simen Portland biasa (OPC) atau abu tandan sawit yang dibakar dan dirawat (TPOFA) dan prestasi GGAM diukur dari segi dari pada, ujian kekuatan tegangan tidak langsung (ITS), modulus kebingkasan (MR), rayapan dinamik (DCT), jejak roda Hamburg (HWTT), prestasi mudah (SPT), dan rasuk lesu empat titik di dalam fasa kedua. Analisis menggunakan teknik pengimejan-3D terhadap permukaan agregat yang pecah dilakukan terhadap sampel yang telah diuji menggunakan ujian
tegangan tak langsung. Kaedah penilaian statistik melalui analisis varians digunakan untuk menganalisis keputusan ujian dalam membuat perincian dan memahami prestasi bahan yang diuji. Keputusan ujian menunjukkan bahawa semua asfalt mastik menunjukkan kelikatan yang lebih tinggi berbanding pengikat asas. Penambahan CaCO3+TPOFA meningkatkan G* tetapi mengurangkan sudut fasa yang dipercayai disebabkan oleh peningkatan kekukuhan asfalt mastik. Oleh itu, menggabungkan CaCO3 dan TPOFA berpotensi meningkatkan rintangan aluran asfalt mastik. Keputusan selanjutnya menunjukkan bahawa penambahan CaCO3+TPOFA ke dalam campuran mempunyai kesan yang signifikan terhadap sifat campuran yang menyebabkan peningkatan rintangan campuran terhadap keretakan lesu. Keputusan ujian SPT dan ujian pengesanan roda dapat mengurangkan keparahan ubah bentuk kekal yang disebabkan oleh gabungan densifikasi dan ubah bentuk aliran sisi. Hasil ujian rintangan lesu menunjukkan bahawa semua sampel menunjukkan prestasi yang baik. terdapat sedikit pengurangan pada tempoh hayat lesu spesimen berusia berbanding sampel yang tak terusia. Nilai ITS dan MR sampel yang terdedah kepada pengusiaan jangka panjang adalah lebih tinggi berbanding sampel yang tak terusia, disebabkan peningkatan ketegangan campuran.
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Apart from realising and implementing sustainable approaches to construct asphalt pavement, a proper selection of materials is also crucial and can be a challenging task. The durability of asphalt pavements includes several aspects that can be related to the mechanical responses of materials, interactions between structural layers, and the influence of non-load related mechanisms such as oxidation, moisture effect, and severe weather conditions. The main purpose of this study was to characterise and understand the effects of ageing on the performance of Gap Graded Asphalt Mix (GGAM) at a range of moisture conditions. To assess the performance of mixture in terms of fatigue cracking and rutting potential, the experimental works were divided into two phases. In the first phase, the effects of CaCO3 with OPC or TPOFA as additives on the rheological properties of bitumen penetration grade 60/70 at high and intermediate temperatures was measured using the Brookfield Rotational Viscometer and Dynamic Shear Rheometer. Then, the samples were prepared by using cubical shaped aggregate, bitumen penetration grade 60/70, and 6% calcium carbonate (CaCO3); with 2% Ordinary Portland Cement (OPC) or Treated Palm Oil Fuel Ash (TPOFA) as filler minerals and the performance of GGAM were measured from the Indirect Tensile Strength (ITS), Resilient Modulus (MR), Dynamic Creep (DCT), Hamburg Wheel Tracking (HWTT), Simple Performance Test (SPT), and Flexural Beam Fatigue test in the second phase. The fracture faces of the samples which were tested using ITS test were analysed using the 3D-image analysis technique. Statistical analysis employing the Analysis of Variance (ANOVA) was employed to analyse the results and to assist in characterising and understanding the material performance. The test results showed that all asphalt mastics exhibited a higher viscosity compared to the base binder. Although the addition of CaCO3+TPOFA increased the G*, it reduced the phase angle which is believed to be attributed to the enhancement of the stiffness and improved the rutting resistance of asphalt mastics. The results further demonstrated that the addition of CaCO3+TPOFA to the mixture had a significant effect on the properties of GGMA which led to the improvement of the mixture’s resistance against rutting and fatigue cracking. It was also found that the SPT and the wheel tracking test can capture the severity of rutting that is caused by the combination of densification and lateral flow deformation. The test results indicated that mixes containing CaCO3+TPOFA performed better and were less susceptible to permanent deformation. The aggregate skeleton within the gap-graded mixture played a crucial role as the main bearing body for the compressive forces. The fatigue resistance test results demonstrated that all samples exhibited good behaviour. It was observed that there was a slight reduction in the fatigue life of the aged specimens compared to the un-aged samples. On the other hand, the ITS and MR of long term ageing samples were higher than those of unaged samples due to the higher stiffness of the mix.
Effects of ageing on mastics and perforanmce of gap-graded asphalt mixtures subjected to moisture conditionings_Foad Mohamed Elkut_A9_2018_MYMY