ANALISIS PENINGKATAN NILAI CBR LEMPUNG PLASTISITAS TINGGI TERSTABILISASI SEMEN DAN ABU DASAR

Abstract

Improvement of soft clay with cement, lime, asphalt, and other additives has been done for few decades. Utilization of waste materials i.e gypsum, marble, rubber; rice hush ash, cane hush ash, saw-dust ash etc. The industrial wasted usage from coal burning process as pozzolanic agent has been proven improving the physical and mechanical properties of soil. This study aims to determine effect of bottom ash combined with cement to improve strength and permeability of high plasticity clay. CBR and hydraulic conductivity tests in the laboratory were carried out to study the changes. Several variations fraction of bottom ash (5%/10%/15%) and cement (3%/5%) were determined in this study. curing processes for 7 days and 28 days was carried out before testing the CBR and permeability. The test results of CBR and permeability of clay were 0.78% and 6E-09 m/sec, respectively. The addition of 3% cement and 5% bottom ash does not qualify soil as aggregate of sub-grade because the CBR value is <12%. The best value was at fraction of 5% cement and 15% bottom ash, with CBR value of 38.60% and k=3.99E-08 m/s. The higher content of cement or bottom ash and curing time, soil properties are better. Composition of 5% cement and bottom ash on ranges of 10%-15% can be used as sub-grade. Keywords: bottom ash, curing, hydraulic conductivity, soaked, stabilization, CBR