Warm mix asphalt (WMA) is a technology that is gaining its popularity due to its ability to reduce asphalt construction temperature hence reducing road construction costs. However, a detailed study on warm mix asphalt is required to assess its performance. This study focus on the moisture susceptibility and aging of WMA asphalt incorporating 0.2%, 0.3% and 0.4% Cecabase® RT. The WMA samples were mixed at 120oC, 130oC and 140oC. All samples were subjected to both short and long term aging using procedures outlined in international standards. Two conditioning methods employed were to subjected specimen to 1 freeze-thaw cycle and 3 freeze-thaw cycles, while those samples that were not conditioned, served as control samples. Upon conditioning, samples were tested for direct tensile test and indirect tensile strengths. The fractured faces of samples were photographed and then taken for image analysis. The results showed that moisture induced adhesive damage increased with the multiple cycles of freezing and thawing. It was also found that hot mix asphalt was more resistant to moisture damage compared to WMA, increases the proportion of adhesive failure compared to un-aged samples. The percentage of broken aggregates fracture surface was not dependent on aging or moisture conditioning method. The effects of moisture conditioning was to reduce the tensile strength of asphalt due to the higher adhesive failure induced.
Asfalt campuran suam (WMA) adalah teknologi yang mulai mendapat sambutan kerana keupayaannya untuk mengurangkan suhu pembinaan asfalt, dan seterusnya menjimat kos pembinaan jalan raya. Namun, kajian yang lebih mendalam masih diperlukan untuk menilai prestasinya. Kajian ini bertumpu pada aspek kerentanan terhadap kelembapan dan penuaan asfalt WMA, dengan penggunaan 0.2%, 0.3% dan 0.4% Cecabase® RT. Sampel WMA telah dicampur pada suhu 120oC, 130oC dan 140oC. Semua sampel telah melalui penuaan secara jangka pendek dan jangka panjang menurut procedur yang digaris dalam standard antarabangsa. Dua kaedah pelaziman kelembapan telah dijalani iaitu 1 kitaran beku-cair dan 3 kitaran beku-cair, manakala yang tidak terdedah kepada pelaziman kelembapan dijadikan sampel kawalan. Dengan pelaziman kelembapan yang telah dilakukan ke atas sampel, ujian tegangan langsung dan ujian tegangan tidak langsung dijalani untuk menguji kekuatan tegangan sampel. Gambar permukaan yang terpecah diambil dan imejnya dianalisis. Keputusan analisis menunjukan fraktur akibat daripada kelembapan meningkat dengan bilangan kitaran pembekuan dan pencairan yang berganda. Rintangan air bagi asfalt campuran panas turut didapati lebih berprestasi baik berbanding WMA. Kadar kegagalan dalam pelekatan bitumen dan agregat meningkat berbanding dengan sampel yang tidak terdedah kepada penuaan asfalt. Peratus pemecahan agregat di permukaan fraktur tidak bergantung kepada kaedah penuaan asfalt atau pelaziman kelembapan. Kesan pelaziman kelembapan yang mengurangkan kekuatan tegangan asfalt adalah kerana kadar kegagalan pelekat antara bitumen dan agregat yang lebih tinggi.
Effects of aging on water sensitivity of asphalt mixtures using image analysis technique