Yulvi Zaika

GRADATION BAND OF SOME TYPES MATERIAL FOR RESERVOIR BASE OF POROUS PAVEMENT

Recent year, reducing of open area and the extreme rainfall are reason for the flood in some city in Indonesia. The drainage and infiltrated well were constructed in some parts of the city could not solve the problem yet. The porous pavement can be applied to reduce run off, rate and pollutants. Reservoir base or sub base is an important layer as part of structure and also temporary store rainfall water before infiltrate to the subgrade. This study assessed characteristic and gradation some types of materials as stone crush, limestone and steel slag for porous pavement and evaluate this performance based on California Bearing Ratio (CBR) and porosity. Naturally these characteristics are contrary, in which for high porosity materials will have low bearing capacity. There are 7 gradations consist of 4 gradations in coarse aggregate and 3 gradations based on Bina Marga (Indonesian Highway Agency). The result showed that CBR of stone crush is high in uniform course material gradation than limestone and steel slag. In the term of porosity, the result completely the same for all materials in which the uniform gradation give the high porosity. It makes sign the influence of hardness and gradation of material will give contribution for bearing capacity and only gradation influence to porosity. The material are suitable for reservoir layer of porous pavement for light traffic load. Gradation band is lied between Bina Marga and NAPA and AASHTO specification.

THE ESTIMATION OF BEARING CAPACITY AND SWELL POTENTIAL OF DEEP SOIL MIXING ON EXPANSIVE SOIL BY SMALL SCALE MODEL TEST

Deep Soil Mixing (DSM) is a ground modification technique to improve soil characteristic. This paper explain the result of laboratory experiment of deep soil mixing (DSM) in small scale. The model have been constructed to estimate field condition. The important properties of expansive soil such as the strength and swelling were investigated. The fly ash was used as binder material to enhance strength and mitigate swell potential. However optimum binder dosage, water – binder ratio and geometrical column (length, diameter and spacing) influenced performance of DSM. Variation of length and spacing of column could be established by considering active zone and the area ratio in the single square arrangement. The required treatment area are determined based on tolerable swelling and allowable bearing capacity. The small scale of DSM construction showed significant improvement of swell and strength properties compare with untreated soil. The empirical model are presented in this research provided reasonable predictions of strength and swelling for in situ condition.