ABC Laying Road Construction

Optimum water of Material by using motor grader

 In order manage optimum water of road pavement, we have to add some water or have to dry the material to achieve optimum water of material by using motor grader 

Adding Water.

The above method of moving a windrow from one side to another can be used to add water to a premixed or single type material. As each layer is exposed the water tanker will place water on
until the mixed material is to the required water content.

Dry over wet material.

If the material is worked in the layers from side to side the wind and the sun will dry the surface of the layer. Over one day quite an amount of water can be removed.

A simple test for optimum water content.

1. Take a handful of the mixed material and squeeze hard in the palm of the hand.
2. Using both hands gently break the roll of material in half.
3. If the material falls apart then it is too dry.
If it is muddy on the hands and sticky it is too wet.
If it breaks clean with no ‘crumbs’ then the material is close to optimum.


Spreading Materials and Shaping of Surface.

1. The surveyors should place the pavement edge pegs on both sides of the formation. The windrow to be spread should be placed just to the centre of the edge of pavement peg on one side.

2. The mouldboard is set to the approx height (thickness) of the layer required with the tilt being in the general position and angle of 45°. A sufficient cut is made into the windrow for the material to flow along the mouldboard and form the layer at the required depth.

3. Using this as a base more material is cut and moved across this surface to spill over the edge and extend the base. On wide  roads  this may take a few passes to get all the material to the far edge and spread.

4. After the far edge pegs have been reached the surface is lightly motor graded to the other side to bring the material to edge pegs.

Mouldboard and the wheels of the motor grader.

Only when the final shape of the finish surface has been approximated should a roller be used. Rolling should start from the outside and move towards the centre, and on curves should start at the inside and move to the outside of the curve.

If ‘Box’ type construction is not being used then the roller should leave the edge 150mm until the rest of the pavement has become firm enough to support the roller.

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