Pengaruh variasi campuran agregat kasar berabrasi tinggi (Kurang lebih 50 persen) dan agregat pecah bernilai abrasi kurang 40 persen pada campuran SPlit Mastic Asphalt (SMA) 0/11
LUQMANULHAKIM, Dr.Ir. Latif Budi Suparma, MSc
2004 | Tesis | Magister Sistem dan Teknik TransportasiKebutuhan material agregat kasar sebagai bahan pembentuk lapisan perkerasan semakin sulit diperoleh. Agregat kasar yang memenuhi speksifikasi dengan nilai abrasi maksimum < 40% semakin lama jumlahnya akan berkurang dan terbatas ketersediaannya.Khusus di beberapa daerah di Yogyakarta banyak terdapat agregat abrasi tinggi yang belum digunakan untuk campuran lapisan pekerasan, dari masalah itu perlu dilakukan penelitian terhadap pemanfaatan agregat tersebut yang mempunyai nilai abrasi tinggi ( ± 50%) yang akan divariasikan dengan agregat bernilai abrasi rendah (<40%) sebagai bahan campuran aspal panas untuk lapisan permukaan perkerasan (wearing course) dengan sistim campuran SMA 0/11. Penelitian ini dilakukan dengan membuat benda uji dari empat variasi prosentase agregat kasar bernilai abrasi tinggi (+50%) dengan agregat kasar bernilai abrasi rendah (<40%). Prosentase dari agregat tersebut adalah 80T/20R (80% agregat kasar bernilai abrasi ( ± 50%) dan 20% agregat kasar bernilai abrasi rendah <40%), 60/40, 40/60 dan 20/80. Pada masing-masing variasi prosentase agregat kasar dibuat benda uji dengan variasi kadar aspal 6,5%; 7%; 7,5%; 8% dan 8,5% untuk mencari kadar aspal optimum dengan menggunakan metode Marshall. Kemudian dibuat benda uji pada kadar aspal optimum dengan perendaman 0,5 jam dan 24 jam yang tujuannya untuk mengetahui nilai karakteristik Marshall dan benda uji untuk menentukan nilai ITS (Indirect Tensile Strength). Hasil penelitian menunjukkan bahwa kadar aspal optimum pada masingmasing variasi prosentase agregat kasar pada campuran Split Mastic Asphalt 100T/0R (100% agregat kasar bernilai abrasi tinggi ( ± 50%) dan 0% agregat kasar bernilai abrasi rendah <40%), 80T/20R, 60T/40R, 40T/60R dan 20T/80R sebesar 7.75%, 7.65%, 7.40% dan 7.25%. Hasil pengujian Marshall pada kadar aspal optimum untuk setiap variasi menunjukkan bahwa semakin besar prosentase kadar agregat kasar bernilai abrasi rendah (<40%) maka stabilitas dan MQ semakin naik (pada variasi 80T/20R; stabilitas dan MQ sebesar 1456.9 kg dan 370.3 kg/mm menjadi 1524.9 kg and 401.8 kg/mm). Perendaman benda uji selama 24 jam menyebabkan nilai stabilitas dan MQ turun dan nilai flow naik apabila dibandingkan dengan nilai perendaman 0,5 jam. Indeks perendaman untuk masing-masing variasi prosentase agregat kasar 100T/0R, 80T/20R, 60T/40R, 40T/60R dan 20T/80R adalah sebesar 81,15%,81,12%, 81,10%, 80,68% dan 80,26%. Nilai Indirect Tensile Strength Ratio (TSR) pada masing-masing terjadi kecendrungan penurunan seiring dengan semakin besar prosentase agregat kasar bernilai abrasi <40% (berturut-turut sebesar 48,10%, 61,07%, 63,68%, 79,30% dan 80,14%).
Recently, it is more difficult to get the coarse aggregate as pavement wearing course former material. The amount of the coarse aggregate which required maximum abrasive value of 40% and also limited. However, especially in Yogyakarta, there is high abrasive aggregate which is not employed yet for pavement wearing mixture, therefore, it is needed to perform the research to get the benefit of aggregate with high abrasive value (± 50%) which will be varied to low abrasive aggregate (< 40%) as a specimen hot asphalt mixture material for wearing course pavement by SMA 0/11 mixture system. This research has been conducted by manufacturing from four percentage variations of high abrasive aggregate coarse (± 50%) and low abrasive of coarse aggregate (< 40%). The aggregate percentage was 80T/20R (80% of high abrasive aggregate coarse ± 50% and 20% of low abrasive of coarse aggregate < 40%), 60T/40R, 40T/60R, and 20T/80R. Each percentage variation of coarse aggregate has been made into sample test with asphalt content variation of 6.5%, 7%, 7.5%, 8%, and 8.5% to find out the optimum asphalt content by conducting Marshall Test. Thus, it has been performed sample test in optimum asphalt content with immersion duration of half an hour and 24 hours, to study Marshall characteristic and sample test value determining the Indirect Tensile Strength (ITS) values. The results showed that the optimum asphalt content of each percentage variation of coarse aggregate in Split Mastic Asphalt mixture 100T/0R (100% of high abrasive aggregate coarse ± 50% and 0% of low abrasive of coarse aggregate < 40%), 80T/20R, 60T/40R, 40T/60R, and 20T/80R was 7.75%, 7.65%, 7.40%, and 7.25%. Results from Marshall Test at the optimum asphalt contents of each variation indicates that the higher the content of low abrasive value coarse aggregate (< 40%) the higher the stability and MQ values (on variation 80T/20R the stability and MQ values were 1456.9 kg and 370.3 kg/mm and on variation 20T/80R those values were increase to 1524.9 kg and 401.8 kg/mm respectively). The immersion of sample test for 24 hour resulted in decreasing the values stability and an MQ but flow value was increased compared to the half hour immersion. In the immersion index for each percentage variation of coarse aggregate 100T/0R, 80T/20R, 60T/40R, 40T/60R, and 20T/80R were 81.15%, 81.12%, 81.10%, 80.68%, and 80.26% respectively. The indirect tensile strength ratio (TSR) of each variation indicated that the higher the percentage of low abrasive value coarse aggregate the lower the TSR values (those were 48.10%, 61.07%, 63.68%, 79.30%, and 80.14% respectively).
Kata Kunci : Campuran Aspal Panas,SMA
