Specification Part 3 - Road & Bridge Works - Urban Administration ...

501. GENERAL REQUIREMENTS FOR BITUMINOUSPAVEMENT LAYERS
501.1. General
Bituminous pavement courses shall be made using the materials described in the following
paragraph. For work of bituminous pavement layers the manual for construction and supervision
of bituminous work shall also be applicable.
501.1.1 Use of bituminous work’s:-
(a) Use of prime coat:-
(i) To plug the capillary voids.
(ii) To coat and bond loose materials on the surface.
(iii) To harden or toughen the surface.
(iv) To promote adhesion between the layer being primed and superimposed bituminous layer.
(b) Use of Tack coat: - It is used to ensure a bond between the new construction and the old
surface.
(c) Use of Bituminous penetration macadam: - The penetration macadam specification was in
vogue as a base material for pavement construction may decades ago. It is not advocated for use
in heavily trafficked situations, for which the more efficient coated macadam is preferred. In India,
it is still used remote areas where it is difficults to transport mixing and laying equipment. It can be
used as a temporary emergency material to repair a pavement damaged by rains and floods.
(d) Use of Built up spray grout:- It is used only for emergency repair work and other temporary
construction.
(e) Use of Surface dressing:- Surface dressing is use in a variety of situation to perform various
functions these are:-
(i) As a surfacing in its own right, in the case of relatively lightly trafficked roads, over gravel or
other untreated road bases, often to prevent gravel loss, and particularly to reduce dust nuisance.
(ii) To protect freshly laid water bound macadam or similar unbound base from the action of
pneumatic tyred vehicles which, unless prevented from doing so, tend to draw out much of the
fines from the macadam and thus deprive it of stability.
(iii) To act as a water proof seal and prevent the entry of water into the lower layers of a road
pavement. For longer term maintenance of roads. It is then known also as a seal coat.
(iv) To arrest the deterioration of an existing bituminous surface which is showing sings of
distress, as part of periodic maintenance of roads, it is then known also as a seal coat.
(v) To increase the skid resistance of smooth surface.
(vi) To act as a temporary bituminous surfacing on newly constructed roads so as to allow for
settlements due to traffic before costlier bituminous layers are provided.
(f) Use of Bituminous macadam:- A layer of bituminous macadam serves as a base/s binder
course, laid immediately after mixing on a previously prepared base.
(g) Use of Dense graded bituminous material: Dense bituminous:- Dense bituminous
macadam is used as a base/binder course for pavements subjected to heavy traffic.
(h) Use of Dense graded bituminous material: Semi Dense Bituminous Concrete: It is used
as a binder/wearing course on roads carrying relatively lower traffic in terms of equivalent
standard axle loads(esa), generally less than 10 msa.
(i)Use of Dense graded bituminous material: Bituminous concrete:- A bituminous concrete
layer serves as a wearing course for heavily trafficked highways.
(j) Use of open grade premix surfacing:- It serves as a wearing course on lightly trafficked
roads or for temporary improvement and maintenance.