construction of flexible pavement
TRANSCRIPT
The Public Works Department establish in the year 1854. At that time PWD was responsible for
the construction of roads,buildings,railways as well as flood control,irrigation and military
works.The organization’s construction works is directly connected to the national programme of
development and reconstruction.
• PAVEMENT-
Pavement is load bearing and load
distributery component of a road.
• PURPOSE OF PAVEMENT-
1. Load support.
2. Smoothness.
3. Drainage.
4. All weather operation.
5. Direction and guidance.
• TYPES OF PAVEMENT STRUCTURE –
Flexible Pavement. (Hot mix asphalt (HMA) pavements)
2. Rigid Pavement. (Portland cement concrete (PCC) pavements)
Construction of Subgrade
Materials- Selected Soil , Moorum , Gravel , Aggregate
maximum 50 mm.
Construction Method –
•The subgrade is constructed by spreading the loose soil and compacting the same at optimum moisture content of the soil in layer.
•The maximum compacted thickness of each layer is generally limited to 200 mm as per MORTH.
Construction of Bituminous Pavement layers
Three types of bituminous layers-
1. Bituminous Macadam.2. Penetration Macadam.3. Bult up spray Grout.
It consist of crushed aggregate and bituminous binder heated and mixed in a hot mix plant at specified temperature , transported to the construction site, laid with a mechanical pawer and compacted by roller.
Material used : Bitumen binder of grade VG -30,20 and Max size of aggregate 50mm.
Bituminous Penetration Macadam Base Course
The coarse aggregate of specified size are first spread and compacted well in dry state. Compected thickness 50-75 mm. After compacting of dry aggregates, hot bituminous binder of specified grade is spread in large quantity on the top of this layer. Filling up a part of void and binding by key aggregate.
It consist of a two layer composite construction of compacted crushed stone aggregate with bituminous binder applied after each layer and key aggregate placed on the top surface of the second layer.