Construction of Gravel Roads
Gravel roads are considered superior to Earthen Roads as they can carry heavier traffic.
this type of road can take about 100 tonnes of Pneumatic tyred vehicle or 60 tonnes of iron tyred vehicles per day per lane.
the camber provided on this type of road is between 1 in 25 and 1 in 30.
Two types of Construction methods are given below.
(I) Feather Edge Type
it is Constructed over the Subgrade with varying thickness, so as to obtain the desired cross slope for the pavement surface.
(II) Trench Type
in the trench type, the Subgrade is prepared by excavating a shallow trench.
The Construction of Gravel Roads may be divided into following steps.
(I) Construction Material
Hard variety of crushed stone or gravel of specified gradation is used.
Rounded stones and river gravel are not preferable as there is poor interlocking.
Gravel to be used for the construction is stacked along the sides of proposed road.
(II) Alignment Location
the central line and Road ages are marked on the ground along the alignment with the help of reference pegs.
(III) Pavement Structure
the layer is rolled using smooth wheel rollers starting from the edges and proceeding towards the centre with an overlap of atleast half the width of roller in the longitudinal direction.
(IV) Opening to Road Traffic
A few days after the final rolling and drying out, the road is opened to the traffic.
