FLEXIBLE PAVEMENT FAILURES IN NIGERIA, POSSIBLE CAUSES AND REMEDIES
CHAPTER ONE
1.0 Â Â INTRODUCTION
Road construction and maintenance is an important desire for development especially in developing countries, market accessibility, economic growth, natural resource exploration, habitat fragmentation, deforestation and the disappearance of wild life are all related to road existence and status. Road constructed and maintained that collapse upon the need of local society and their extension in the country. Also the priority of investment (political needs, industrial stations, or agricultural habitats and zones) is address when decisions usually taken for new construction of roads and for maintenance.
Road transport is the moving engine for other sectors and activities in developing countries. It provide access to industry, agriculture, investment, health services, and education through providing of goods and passengers. And the lack of good roads or the existence of poorly maintained or poor conditions of roads are barriers to the development and investment in developing countries.
The accurate and sensitive prediction of rutting development is an essential element for the efficient management of pavement system by poor testing and maintenance to keep road in a good condition. Road defect are visible evidence of an undesirable and avoidable conditions in the pavement affecting serviceability, structural conditions or appearance, performance and function. Also, the definition of ROAD DEFECT includes, any part of a road, highway or construction site that does not meet regulation for safe roads. In addition to that; road defect are most often causes injuries to the people or damage to vehicle that include; inadequate roads shoulders, lanes that are uneven, pavement that uneve, improperly marked sign malfunction stop construction negligence and municipal negligence. OKIKBO,(2012).
1.1 Â Â Background of Study
Construction is one of the primary activties in which human more large quantities of earth materials. From the earliest times, one of the strongest indication of the society’s level of development has been it’s road system. Road makes a crucial contribution to economic development and growth and bring important social benefits.
Kaare, Kuhi and KOPPEL (2012) pointed that flexible pavement deteriorate under the effect of traffic loads and climate. This effect depend on the technology applied in material construction and application on the road, but the greatest effect depend on traffic loads and volumes proposed to be repeated on road section. ABHIJIT (2011) investigated the effect of poor drainage on the road condition and found that the increase in moisture content decreases the strength of pavement. Therefore, poor drainage causes the premature failure of the pavement tends to crack at some point of their life under the combination action of traffic and the environment and climate conditions. WEE ET AL.., (2009). Wisconsin department of transport investigate the pavement fatigue as a result of the number and weight of axle loads. They also discusses how wheel loads, number of truck axles, number of truck tires quality ofsubgrade, pavement thickness and changing seasons contribute to pavement failure.
In addition, climate conditions were seen to have seen to have an effect on road deterioration, vehicles operating costs and safety and the environment ANTALA ET, AL (2011). Transport canade (2015) indicate that climatic factors are a major cause for pavement deterioration. It is a fact that temperature, frost and thaw action as well as moisture are factors that can cause certain types of pavement deterioration Transport canada(2005). These factors can also intensify pavement deterioration on caused by heavy vehicles.
Hariscandia (2004), found that potholes, cracks, edges defects, depressions and corrugation are significant road defects observed in the field. At the same time he emphasized that traffic, age, road geometry, weather, drainage, construction quality as well as construction material, maintenance policy play the major role as road deterioration agents. Korkiala_tanttu and Deason (2007) sugguested that in the pavement or embankment, water plays a primary role in giving shorter service life and in increasing the need of rehabilitation measures.
Abdulkareem and Adeoti (2004) examine the method of road maintenance in Nigeria. To do so, they defined and analyzed the causes of structural failure of highway and suggest some factors; action of wheather, rain and heat, unstable ground condition and poor drainage, poor economic material and methods post construction activities like digging of trenches along the road etc, poor workmanship and inadequate maintenance. On his study on Nigeria highway, Okido (2012) has indetified some of the factors that causes highway failure. These factors are; poor design, poor workmanship, poor maintenance of already built highways, use of low quality materials in construction work and applying of heavy traffic that were not meant for the road.
Futhermore, he also suggest that the following will lead to highway failure such as; poor highway facilities, no knowledge base, inadequate sanction for highway failure, no local standard of practice, poor laboratory in situ test on soil and week local professional bodies in highway design, construction and management.
1.2Â Â Â Statement of Problem
The problem of pavement failure in Nigeria has become an embarrassing stigma. In some part of this country, normal interaction has been frustrated by bad pavement. Road user are in distress as they are not identifying the proposed factors that causes the deterioration of highway in Nigeria from client perspective comparing them with the contractor’s perspective comparing them with the relative importance for the use by consultants and main road contracting firms. A questionnaire was
