PENGARUH PENAMBAHAN STONE DUST TERHADAP NILAI CBR DISAIN PADA STABILISASI TANAH CIMANGGIS DENGAN MEMPERTIMBANGKAN GRADASI STONE DUST

Abstract

Soil stabilization can be found with added stone dust, which has been applied in the highway Cinere-Jagorawi Section I construction, where the addition of stone dust with comparison 2 : 1, can increase the bearing capacity (CBR value) of soil becoming 30% on soaked condition. The addition of stone dust is not effective because the based of requirement the CBR value is designed only 6%, so the amount of stone dust will be minimized. In the site of building works, the gradation of stone dust can be classified either in well graded or poorly graded. So, if the stone dust on those gradation variations have been added, it will influence the value of design CBR. Therefore, the aims of this research is to know the different influences by adding stone dust between well graded and poorly graded, also is to know the percentage of adding stone dust effectively and efficiently from both gradations, to reach the design CBR value amount of 6% on soaked condition, this amount is based on technical requirement as a sub-grade. These problems can be solved by doing experiment research to models that made of soil and stone dust mixture which percentage addition between 5% and 25% , either well graded or poorly graded. Based on that research can be concluded : 1) addition of stone dust either well graded or poorly graded will influence significantly to design CBR value. By addition more stone dust will increase the design CBR value, 2) there is no different significantly to design CBR value of stone dust addition content of 5% to 25%, between well graded and poorly graded, and 3) to reach the design CBR value 6% is needed stone dust addition approximately 20%. Keywords : Stone Dust, Design CBR Value, Soaked, Well Graded and Poorly Graded. Abstrak Stabilisasi tanah dengan cara penambahan stone dust telah diaplikasikan pada pembangunan jalan tol Cinere-Jagorawi seksi I, dimana penambahan stone dust dengan perbandingan 2:1 dapat meningkatkan daya dukung (nilai CBR) tanah dari 2,15% menjadi 30% dalam kondisi soaked. Penambahan stone dust ini kurang efisien karena nilai CBR disain yang disyaratkan hanya sebesar 6%, sehingga jumlah stone dust yang ditambahkan bisa diminimalisir. Disamping itu pada kondisi di lapangan, gradasi stone dust dapat digolongkan dalam “well graded” maupun “poorly graded” , sehingga apabila stone dust yang memiliki perbedaan gradasi tersebut ditambahkan kemungkinan akan memberi pengaruh yang berbeda terhadap nilai CBR disain yang dihasilkan. Oleh karena itu, penelitian ini bertujuan untuk mengetahui pengaruh penambahan stone dust yang bergradasi “well graded” dan “poorly graded” serta mengetahui persentase penambahan stone dust yang efektif dan efisien dari kedua gradasi tersebut guna mencapai nilai CBR disain sebesar 6% yang merupakan salah satu persyaratan sebagai subgrade. Permasalahan tersebut dapat diselesaikan dengan melakukan penelitian dengan metode eksperimental terhadap benda uji yang terbuat dari campuran tanah dan stone dust dengan kadar 5%- 25% baik yang bergradasi “well gradaed” maupun “poorly graded”. Dari penambahan tersebut, dapat diketahui bahwa : 1) penambahan stone dust baik dengan gradasi “well graded” maupun “poorly graded “ memberikan pengaruh yang signifikan terhadap besarnya nilai CBR disain, dimana semakin tinggi kadar stone dust, semakin tinggi pula nilai CBR yang dihasilkan, 2) tidak ada perbedaan yang signifikan terhadap nilai CBR disain akibat penambahan stone dust dengan kadar 5% - 25% antara yang “well graded” dan “poorly graded”, 3) untuk mencapai CBR disain sebesar 6% diperlukan penambahan stone dust sebesar 18,7 %. Kata kunci : Stone Dust, Nilai CBR Disain, Soaked, Well Graded dan Poorly Graded.