Pengaruh Zat Additive Polimer Lateks terhadap tanah lempung dengan masa perawatan satu hari

IBRAHIM, Dr.Ir. Ahmad Rifa'i, M.T

2005 | Tesis | S2 Teknik Sipil

Beberapa konstruksi jalan raya di Indonesia dibangun di atas tanah lempung. Kuat dukung tanah lempung sangat dipengaruhi kadar air, dalam keadaan kering mempunyai kuat dukung tinggi dan dalam keadaaan jenuh akan mempunyai kuat dukung yang rendah. Kadar air akan mempengaruhi sifat kembang susut dan parameter kuat geser tanah. Konstruksi jalan yang dibangun di atas tanah lempung sering mengalami kerusakan, misalnya: jalan akan retak atau bergelombang sehingga jalan akan mengalami kerusakan sebelum mencapai umur rencana. Untuk mengatasi permasalahan tanah lempung dimana kuat dukungnya dipengaruhi oleh kadar air, salah satu alternatif dilakukan perbaikan dengan cara stabilisasi. Penelitian ini menganalisis perilaku tanah lempung Gading km.33 Wonosari dipadatkan 95% γd,max dengan penambahan polimer lateks 2,5%; 5% dan 10% masa perawatan 1 hari, kemudian dilakukan pengujian berupa sifat-sifat tanah, triaksial unconsolidated undrained (UU), California Bearing Ratio (CBR), tekan bebas (unconfined compression), dan matric suction. Hasil penelitian, menurut klasifikasi Unified termasuk kelompok CH dan menurut klasifikasi AASHTO termasuk kelompok A-7-6. Penambahan polimer lateks akan menyebabkan properties tanah batas cair (LL) menurun dengan batas plastis (PL) tetap sehingga indeks plastisitas (PI) menurun, kemudian persentase butiran mengakibatkan jumlah fraksi halus menurun dengan gradasi lempung meningkat. Penambahan polimer lateks akan bekerja efektif pada pengujian CBR perendaman yaitu meningkatkan nilai CBR dan mereduksi pengembangan tanah (swelling), kemudian untuk pengujian tekan bebas akan efektif dengan penambahan garam anorganik. Perilaku matric suction akan meningkat dengan menurunnya kadar air tanah. Maka dapat disimpulkan bahwa polimer lateks bekerja mengisi dan menyelimuti pori-pori tanah sehingga meningkatkan kekedapan tanah terhadap penambahan air dan meningkatkan kekuatan tanah saat penjenuhan tanpa merubah sifat fisis tanah.

Some roadway in Indonesia was constructing on the expansive clay. The bearing capacity of expansive clay was very influenced by water content; it will weakness in the saturated condition and will have strength in a dry condition. Water content will influence its shrinkage soil and shear strength soil parameters. The construction of rail road which was built on the clay was often broke down; in example the road will be cracked and waved before the used of the road is ended. To solve the problem, which bearing capacity was influenced by water content, there is an alternative can be done which is stabilization This research is analysed clay Gading km.33 Wonoari compacted 95% γd,max with addition polymer latex 2.5%; 5% 10% curing 1 days, and then execute test as triaxial unconsolidated undrained (UU), California Bearing Ratio (CBR), unconfined compression and matric suction with presentation polymer latex variation. This research gives a result that the soil is classified as a CH (based on Unified classification) and A-7-6 (based on AASHTO classification). The additive addition will make its Liquid Limit (LL) goes down with Plastic Limit (PL) stabile, and it makes Plastic Index decrease. The percentage of grains makes its soft fraction down and the gradation of clay is up. The additive addition works effectively at CBR soaked with the improvement of CBR value and reduces swelling soil. Unconfined test will also effectively with the addition of inorganic salt. The behaviour of metric suction will improve as the decreasing of soil water content. The research conclude that the additive polymer latex can fill and cover the pore of soil and it makes the impermeability improve to water addition and soil strength when it becomes saturated without changes any physical characteristic.

Kata Kunci : Konstruksi Jalan Raya,Tanah Lempung,Polimer Lateks, polymer latex, stabilization, clay