INDEX

• Company Profile

• Introduction

• Type of Pavement

• Layers of flexible Pavement

• Construction of Subgrade

• Construction of subbase course

• Construction of base course

• Bitumen layer

Company Profile

The Public Work 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 organizations construction

works is directly connected to the National Programme of development and

Reconstruction.

INTRODUCTION

• PAVEMENT-Pavement or Road is an open, generally public way for the passage of vehicles, people, and animals.

• PURPOSE OF PAVEMENT-:1)Smoothness

2)Drainage

3)Direction and Guidance

4)All weathear Operation

Layers of flexible Layers of flexible Pavement Pavement

• Earth work

• Soil subgrade

• Sub base Course

• Base course

• Surface course

Pavement Types  

Pavements can be generally classified into two broad categories:

1.Flexible pavements- These  pavements (sometimes called bituminous pavements), which may or may not underlying layers of 

stabilized or unstabilized granular materials on a prepared subgrade.  These types of 

pavements are called "flexible" since the total pavement structure bends (or flexes) to 

accommodate traffic loads.  2.Rigid pavements -These are portland cement concrete (PCC) pavements, which 

may or may not incorporate underlying layers of stabilized or unstabilized granular materials.

Earth WorkEarth Work

• Soil filling

• Spreading & Leveling

• Compaction

SUBGRADE LAYERSUBGRADE LAYER

• Subgrades are commonly compacted before the construction of a road, pavement or railway track, and are sometimes stabilized by the addition of asphalt, lime, portland cement or other modifiers. The subgrade is the foundation of the pavement structure, on which the subbase is laid.

• The load-bearing strength of subgrade is measured by California Bearing Ratio (CBR) test.

SUBBASE COURSESUBBASE COURSE

•  Subbase is the layer of aggregate material laid on the subgrade with thickness usually 100–250mm.

• Unbound granular materials are usually crushed stone, crushed slag or concrete, or slate.

BASE COURSEBASE COURSE

• The base course is constructed directly above this layer.

• A layer of material of specified thickness constructed on the subgrade or sub-base of a pavement to serve one or more functions, such as distributing loads, providing drainage, or minimizing frost action.

Bituminous Macadam

It consist of crushed aggregate and bituminous binder heated and mix in a hot mixing plant at 

specified temperature, transported to the construction site laid on surface and compacted by 

Roller. Maximum size of aggregates used is 50mm.

Finishing of SurfaceFinishing of Surface(Rolling)(Rolling)