There can be variations on the exact techniques of motor grader that are described here, but generally similar type methods will be used with only operator preferences and site conditions changing.
Mixing Materials and Adding Water by using motor grader.
Some times two types of material may have to be blended in order to get the specified base or sub-base material. For example, Natural hillside gravel may have a high clay content, which can be reduced with the addition of sand.
A method of combining these two materials is as follows;
1. Stockpile the gravel material along the road at the correct rate. Use the motor grader to level out this material into a pad just wide enough to drive the tipping trucks on. The blade can be set at the general tilt and say 30° and the motor grader drives over the stockpiles flattening and shaping them. If a square blade is used then there is no control over the material flow and segregation of the material can occur.
2. Place sand on the previous layer using the same technique as above.
3. In order to give the motor Grader as much room to work, no pavement edge pegs are placed until the material has been completely mixed.
With the mouldboard being set at the mixing tilt and placed at approx 45° and raised on the side away from the windrow, a cut is taken from the side so that both layers are cut. The material as it
moves along the blade is rolled by the shape of the mouldboard and so mixed.
If water is to be added then it is placed on the new pad that has been formed using a Water Bowser with spraybar fitted. This is repeated on each layer.
This is repeated with new layer being placed on the top of the previous using the above method. When all the material has been moved they the motor grader will then form a new windrow on the other side of the roadway.
4. Using the above techniques of motor grader , the material is moved to the opposite side of the roadway. This is repeated, moving the material from side to side, for 4 to 6 times by which time the material should be thoroughly blended and the correct percentage of water has been added. The operator will then tell the surveyors to place edge pegs on one side of the road formation and place the windrow approx 100 to 200 mm from these pegs.