THE EFFECT OF MOISTURE CONTENT ON PAVEMENT FAILURE ALONG LAGOS – IBADAN EXPRESSWAY

Abstract

Highway pavement failure in Nigeria has increased in the past decades despite the huge amounts of money appropriated annually for rehabilitation. Apart from losses due to fatalities and disruptions to normal daily activities, annual loss to structural deficiency, functional obsolescence and operating cost is about ₦133 billion. One of the causes is associated with inadequate moisture in pavement materials. This study aimed at examining the effect of moisture on other geotechnical parameters as the factor of pavement failure along Lagos–Ibadan Expressway. Samples were collected at the failed and stable portions on some selected road segments and subjected to laboratory tests including Natural Moisture Content (NMC), Linear Shrinkage (LS), particle size distribution and California Bearing Ratio (CBR). Pavement Distress Score (PDS) was also determined on these road segments. Data generated were subjected to statistical analyses and Models for predicting road pavement performance were also developed. The NMC along the failed sections was on the high side (ranged from 13.11% to 26.89%) compared with the stable sections (ranged from 11.11% to 16.40%). The maximum dry density(MDD) for the samples at failed and stable sections ranged from 1550 kg/m3 to 1860 kg/m3; 1650 kg/m3 to 1980 kg/m3 respectively while the Optimum Moisture Content(OMC) ranged from 8.30% to 20.30%.