Effects of Waterlogging on the Performance of Ruvu to Mlandizi Road Pavement

Abstract

Waterlogging is a problem on the road embankment constructed 
from Ruvu to Mlandizi. During the rainy season, the rainwater 
and floods from the Ruvu River cause the water table to rise, and 
the water tends to infiltrate the embankment. This scenario has 
led to severe defects on the road pavement, such as potholes, 
alligator cracks, heaves and ruts, regardless of frequent 
maintenance conducted. This paper establishes a methodological 
approach aimed at assessing failures of Ruvu–Mlandizi road 
pavement sections. A levelling survey was conducted to establish 
the topographical nature of the road section. The determined 
levels were compared with specified requirements of road design 
against actual embankment heights. The results indicate that 
there was a need to raise the embankment to appropriate heights 
to accommodate flood levels and overcome water overtopping 
the road. The excavation of two trial pits to determine the actual 
depth of the water table on a road section was also conducted. 
Results reveal that the water table was at a depth of 0.3 m from 
the top of the improved subgrade surface. Based on the study 
findings, it is recommended to improve the road embankment 
heights of 1.5 m and apply appropriate methods to reinstate the 
situation.