THE IMPACT OF WATER SUBMERGENCE AND HIGH PRESSURE PISTON LOADING REPETITION ON SOAKED-CBR VALUE OF SUBGRADE AND SUB-BASE LAYERS

Road pavement deterioration is a common problem that occurs in many countries. Many researchers found that the cause of deterioration is water submergence, heavy vehicle tire pressure, and cyclic load. From those results, it is known that there is no research on road pavement deterioration caused by combination of water submergence and heavy vehicle repetition that measured based on the soaked-CBR value. Therefore, this research was conducted to find the answers. Material used in this study was selected fill material (material-1) and aggregate B (material-2). The study was conducted in 2 steps. In Step-1, six samples for each of materials were compacted at their OMC values. Afterwards, 3 of 6 samples for each of materials were soaked; the remaining were made in un-submerged condition. In Step 2, cyclic load with pressures of P=50psi, 100psi, and 150psi were applied; repetition number of cyclic load for each pressure applied was n=0, 300, 600, 900, 1200, 1500. Soaked-CBR value was determined every time finish applying at each the cyclic load. The results show that soaked-CBR value of material-1 is always lower than of material-2, in all condition. Decrement of soaked-CBR value of material-2 in submerged condition caused by cycle loading pressure is more significant compared to the one of material-1. Soaked-CBR value of material-2 is affected by water submergence regardless the loading pressure and number of cyclic repetitions applied. Grain size distribution of materials has significantly affected to change of their soaked-CBR values when cycle loading applied especially for material in submerged condition.