STEP FOR PREPERATION OF SUBGRADE DURING HIGHWAY CONSTRUCTION

1) The selected soil in loose condition is spread to the required grade and cross slope in layer of desired thickness using appropriate equipment such as over the prepared surface.

2) Additional water as required is sprayed so as to obtain the OMC of the soil determined from the laboratory compaction test.

3) The soil with added water is mixed thoroughly using appropriate equipment so that water gets disturbed in the soil layer uniformly, the mixed soil is spread again to uniform layer thickness, grade and cross slope.

4) The soil layer is compacted by rolling using the selected equipment so as to obtain the specified density.

5) The process is repeated until the desired compacted thickness of sub grade is achieved