1.1 Introduction
Water can be one of the most damaging elements to asphalt pavement because it has a lot of adverse effects on pavement performance. Moisture damage decreases strength and durability of asphalt mixtures due to the presence of water. This usually occurs when the bond between the asphalt cement and the fine coarse aggregate is lost. As moisture penetrates this weakness, the damages and pavement deterioration speeds up. Some moisture damages and distresses that can occur in asphalt pavement are: cracking, stripping, rutting, bleeding and failures.
When cracks form in asphalt, it allows for water to seep under the surface, which is damaging to the base beneath. Each time it rains and this happens, the weakness, damages, and pavement deterioration rate increases. This damage is often not visible from above, but the damages being caused are serious and can be costly to fix. If your leave your pavement vulnerable to water penetration for too long, potholes and other large structural deterioration can occur.
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Road pavement construction has experienced many significant problems mainly in sub-base and base design and construction over the years in this country (Nigeria). Road pavement construction has experienced many significant problems mainly in sub-base and base design and construction over the years in this country (Nigeria). Nowadays, many billions of Naira is spent on road construction and maintenance each year, and road transport in the primary method of mobility for Nigeria people or goods, Transport constitutes about 10% of the gross national product of the Nigerian union and more than 80% of the total transport of people and goods is provided the infrastructure.
Water has lots of adverse effects on pavement performance. In fact, moisture damage in asphalt pavements is global concern. Moisture damage can be defined as the loss of strength and durability in asphalt mixtures caused by the presence of water. Hence, it’s the need to correctly identify the problem and isolate issues of contributing factors like material variability and construction practices for a better understanding of water effect on pavement deterioration.
Investment in road construction and maintenance in Nigeria is therefore at a very high level and any improvement can have a significant effect on the Nigeria economy. Not only will well maintained roads and highway contribute economically, for they are also essential for social development of Nigeria. On the other, the deterioration of roads can have serious consequence for the safety and comfort of roads user.
When it comes to paving, Asphalt material is the most popular because of it its quality features it has such as looks good, lasts long, and is generally low maintenance. Moisture damage can be defined as the loss of strength and durability in asphalt mixtures caused by the presence of water. Moisture damage is induced by the loss of bond between the asphalt cement or the mastic (asphalt cement, the mineral filler and small aggregates) and the fine and coarse aggregate. Moisture damage accelerates as moisture permeates and weakens the mastic, making it more susceptible to moisture during cyclic loading.
Historically, six contributing mechanisms have been identified associated with moisture damage: detachment, displacement, spontaneous emulsification, pore pressure induced damage, hydraulic scour, and the effects of the environment on the aggregate–asphalt system. However, it is to be mentioned that moisture damage is not limited to a single mechanism but is the outcome of a combination of these mechanisms (Little and Jones, 2003). Santucci and Aschenbrener (2003) have identified the following factors that contribute to adverse effects of water in asphalt pavement. Finally, moisture damage mechanisms results in the following distresses like, Stripping, Bleeding, Rutting, Corrugation and Shoving, Cracking, Raveling, Localized failures.
Therefore, in Ogbese/Akure Junction, Akure Owo Highway where the research was carried out, the activities that was conducted is to know the Effect of Water in an Asphalt Road Pavement.
1.3 Statement of Problems
Investigation revealed that when hiring a professional paving company, they have extensive training to understand the proper techniques, materials, and calculations for your particular project to ensure optimal water permeation protection. If the pavement install and structure application is incorrect (the base layer), the pavement’s lifespan will be significantly lower than it should be, causing premature pavement deterioration.
Asphaltic Pavement deterioration comes as a result of someone leaving his pavement vulnerable to water penetration for too long, potholes and other large structural deteriorations can occur. At the present time as Nigeria continues to experience climate change, these regular maintenances are particularly important.
The problem of premature pavement failures in the study area has necessitated the need for further research to ascertain remote causes and means of improving pavement strength in the region. The 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, the pavement bituminous material on the road have disappear.
1.4 Aim and Objectives of Study
The aim of the study is to determine the Effect of Water in an Asphalt Road Pavement using Ogbese/Akure Junction, Akure Owo Highway as a case study. In achieving this aim, the following specific objectives were laid out as follows:
- To determine the relationship between water and asphalt pavements;
- To examine the impact of water on asphalt road pavements;
- To assess the methods used in repairing the deterioration;
- To analyze the effect of water in asphalt pavement;
- To analyze the solution to such effects; and
- To study the effect of water on pavement made of asphaltic material.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- Is there any relationship between water and asphalt pavements?
- What are the methods used in repairing the deterioration?
- What is the effect of water in asphalt pavement?
- What is the solution to such effects?
- What is the impact of water on asphalt road pavements?
- What is the effect of water on pavement made of asphaltic material?
1.6 Research Hypothesis
In order to pursue the objective of this study, the following generalized statements have been designed to guide and aids in obtaining the result for the experiment to be conducted. For this work, the null hypothesis will be represented with H0 while the alternative hypothesis will be represented with hypothesis H1.
Hypothesis One
- H0: There is no significant effect of water on pavement made of asphaltic material of Ogbese/Akure Junction, Akure Owo Highway on traffic capacity
- H1: There is a significant effect of water on pavement made of asphaltic material of Ogbese/Akure Junction, Akure Owo Highway on traffic capacity
Hypothesis Two
- H0: There is no significant relationship between water and asphalt pavements
- H1: There is a significant relationship between water and asphalt pavements
1.7 Significance of Study
The study will broadly provide information on the actual traffic volume and the capacity of traffic and will help in used for possible traffic planning and design. It shall lead in proper construction of highway and remedy that will possible give a lasting solution and reduction in road failures.
This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.8 Scope of Study
The scope of the research is focused on the Effect of Water in an Asphalt Road Pavement using Ogbese/Akure Junction, Akure Owo Highway as a case study. When cracks form in asphalt, it allows for water to seep under the surface, which is damaging to the base beneath. Each time it rains and this happens, the weakness, damages, and pavement deterioration rate increases. This damage is often not visible from above, but the damages being caused are serious and can be costly to fix.
1.9 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).
1.10 Definition of Terms
Pavement Failure: 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.
