| dc.description.abstract | The prosperity of any nation depends to a large extent on the
effectiveness and efficiency of its communication system.
The economic significance of road construction and maintenance
cannot therefore be overemphasized.
The objective of this research work was to evaluate parameters
of structural and functional performance/serviceability of
road pavements by conducting field tests (elastic deflection
and radius of curvature of deflection profile) and condition
surveys (rideability, cracking, rutting and surface roughness).
The usefulness of these parameters in estimating maintenance
requirements was tested.
In addition, Finite Element Method (FEM) was used to
theoretically analyse the structural integrity of the road
pavements that were tested in the field and both field and
FEM compared.
Before the above work was done, the highway maintenance system
operational in Kenya was studied, and the findings are given
as a complete work in Chapter 2.
Upon the analyses of condition survey data, an index equation
was established which indicated that rideability is affected
more by the extent of rutting than by either cracking or
roughness. The equation was found practical and could be
used to determine the serviceability of the road section using
objective measurement of surface defects.
A method developed from first principles to determine the
radius of curvature of deflection profile was found practical
and the values of radii compared well with those determined
using the analytical method of the Ministry of Public Works
(MoPW).
The philosophy of the criterion proposed by Leger and Autret
(1972) for evaluating structural condition from deflection
measurements was found applicable but the limits require
adjustment to suit local road environment.
FEM predicted well the maximum deflection and the deflection
profile of pavements consisting of non-viscoelastic bases
and asphalt concrete surfaces. The elastic moduli of pavement
materials given by MoPW were found practical.
The institutional capacity of the highway maintenance
organisation in Kenya was found inadequate. Further, funds
allocated to road maintenance were found to have below
requirements in the recent years. | en |
