INVESTIGATION INTO ASCERTAIN THE CAUSES OF FAILURE AND PRESENT TRAFFIC CAPACITY OF HIGHWAYS

Thesis Overview

INTRODUCTION
In construction of highway, generally the roads are not designed to last forever. It is been designed to serve some purpose for a specific time. As it can be seen in engineering work, the life span of a road is always an important factor that must be taken into consideration as one of the criteria for the construction. This really depends on the factors like construction procedure and consideration, the soil water relationship, quality of workmanship during the construction and the type of maintenance culture adopted.
Many roads (Highway mostly) are seen widely as attaining the state of failure and show signs of distress before the expected life span used for construction is reach, due to the lack of factors such as lack of maintenance culture etc. many of our road today serve as death trap and hang out for hoodlums going by the number of accident recorded daily on them as a result of bad paved road.
Pavement failure can be defined as the failure of the constructed layer of durable material of specified thickness, usually of concrete, asphalt or bituminous materials assigned to carry wheeled vehicles. Due to the number of load passing through a pavement structure, some deflection of the surface and underlying layers occur. The deflection can be as a result of the excess load, poor material usage, and poor road foundation resulting from the nature of the soil or groundwater rise in the area of high groundwater level. If layers are lacking in strength, repeated applications causes roughening and cracking that ultimately lead to failure of the pavement structure.
The construction of the Eliozu-New Airport road, which was constructed a while ago, sudden failure due to improper investigation of either the soil composition or traffic capacity situation in the said section of the road networking, lack of proper drainage to control the effect of rise in groundwater level. The pavement thickness of the road section as measure was about 3.87inches (98.3mm) and the width of the dual carriage way about 7.9m with no proper shoulder and drainage provided.
The effort of put in controlling the rate of failure and provision for annually increase of traffic capacity has been a thing of burden to the government of the River State in particular and the Federal government in general. By questioning and observation, failure of the said Eliozu-New Airport road as it problem from compounded presence of water coming out at a particular points on the road surface poor material and workmanship and pressure from increasing traffic capacities on the road pavement of which the government is making provision for overhead bridge which is currently in construction and it is found out that most at a point like Eliozu junction by ABC shuttle, the pavement bituminous material on the road have disappear.