STABILISASI TANAH LEMPUNG DENGAN CAMPURAN KAPUR DAN ABU SEKAM TERHADAP DAYA DUKUNG PADA LOKASI MEDAYU SURABAYA

Clay Soil Stabilization with Lime and Rice Husk Ash Mixture on Bearing Capacity at Medayu, Surabaya

Tanah lempung ekspansif di kawasan Medayu, Surabaya menunjukkan daya dukung rendah yang menyebabkan distorsi struktural pada bangunan. Penelitian ini mengkaji efektivitas stabilisasi tanah menggunakan kombinasi kapur dan abu sekam padi terhadap peningkatan daya dukung melalui pengujian California Bearing Ratio (CBR). Metode eksperimental diterapkan dengan variasi campuran abu sekam padi 0%, 15%, 30%, dan 45% dengan kapur tetap 10%. Karakterisasi tanah asli menghasilkan batas cair 86%, batas plastis 65,77%, indeks plastisitas 20,23%, dan nilai CBR 0,05%. Hasil pengujian menunjukkan komposisi optimum tercapai pada campuran 30% abu sekam padi dengan 10% kapur, menghasilkan peningkatan nilai CBR hingga 67,47% pada penetrasi 0,1 inci dan 74,93% pada penetrasi 0,2 inci. Peningkatan daya dukung terjadi melalui reaksi pozzolanik antara silika amorf abu sekam dengan kalsium hidroksida membentuk kalsium silikat hidrat yang bersifat cementitious. Campuran 45% abu sekam menurunkan efektivitas stabilisasi menjadi 26,24% dan 33,97% akibat ketidakseimbangan stoikiometrik. Penelitian memvalidasi pemanfaatan limbah agroindustri sebagai material stabilisasi berkelanjutan untuk perbaikan tanah ekspansif pada konstruksi infrastruktur.

Kata Kunci: Abu sekam padi, California Bearing Ratio, kapur, stabilisasi tanah, tanah lempung ekspansif

Expansive clay soil in the Medayu area, Surabaya exhibits low bearing capacity causing structural distortion in buildings. This research examines the effectiveness of soil stabilization using a combination of lime and rice husk ash on bearing capacity improvement through California Bearing Ratio (CBR) testing. Experimental methods were applied with variations of rice husk ash mixtures at 0%, 15%, 30%, and 45% with constant 10% lime. Characterization of original soil yielded liquid limit of 86%, plastic limit of 65.77%, plasticity index of 20.23%, and CBR value of 0.05%. Test results indicate optimum composition achieved at 30% rice husk ash mixture with 10% lime, producing CBR value increase up to 67.47% at 0.1-inch penetration and 74.93% at 0.2-inch penetration. Bearing capacity improvement occurs through pozzolanic reaction between amorphous silica from rice husk ash and calcium hydroxide forming calcium silicate hydrate with cementitious properties. The 45% rice husk ash mixture decreased stabilization effectiveness to 26.24% and 33.97% due to stoichiometric imbalance. The research validates utilization of agroindustrial waste as sustainable stabilization material for expansive soil improvement in infrastructure construction.

Keywords: California Bearing Ratio, expansive clay soil, lime, rice husk ash, soil stabilization