COMPLETE SCHOOL PROJECT TOPICS & MATERIALS :
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CHAPTER ONE
INTRODUCTION
1.1 Background of the study
It is logically true that a nation’s economic growth can also be an index of its available infrastructure; Roads, Buildings, and Dams etc (Huang et al., 2014). The inadequacy of this infrastructure to serve their intended use during their lifespan is a major factor to the nation’s economic drawbacks. The developed nations who know the relevance of civil infrastructure, and their significance to the nation’s economy and quality of life, have taken extra care to build, and sustain them (Huang et al., 2014).
The term “structural integrity” has been introduced for objects and structures prone to fracture to describe an important problem in the case of failure in service, sometimes with no warning, as is the case for welded structures (Kristine and Nathaniel, 2014). On the other hand, many objects maintained their integrity during centuries and even millennia, but generally their originally intended use is no more actual. Today they represent valuable monuments and indicate historical development of civilization. In many cases their integrity is intact and can be restored by only small interventions
The assessment of properties of an existing structure with a view to evaluating its performance is very crucial. In reinforced concrete design one of the most important data that is required for analysis is the compressive strength of concrete (Mirmiran, 2001). The compressive strength is usually determined in the laboratory by casting cubes and subjecting them to different loading conditions until failure occurs or alternatively by taking core specimen via drilling from an existing structure (Samia and Necer, 2014). In most cases, however, laboratory molded cubes may not represent the actual condition of the structural concrete and so also the drilled specimen due to risk of loss of structural stability (Miretti et al., 2004).
In civil engineering work, when the integrity of an existing structure is in question or there is a quest for additional modification, the initial examination that is required to provide a reliable data is the integrity test (Kristine and Nathaniel, 2014). This normally begins with Non Destructive Test (NDT) which is applicable in all types of structures such as buildings, bridges, pavements, foundations and dams (Saleem et al., 2012). NDT is generally described as testing that imparts little or no damage to concrete although it usually requires sampling or removing a small amount. It is used for quality assurance, identification of problems, concrete repair and quality control (ACI, 2003). The process involves determining how reliable an existing structure is able to carry existing and future loads and fulfill the tasks for a given time period. The major undertaking for such assessment is to ensure that a structure or part of the structure do not fail under loading. Thus, responsible authorities or owners of properties, usually carryout condition assessment of structural elements or ordered integrity evaluation for structures to determine the level of structural soundness/adequacy to quest for redevelopment of buildings (Rucker et al., 2006). In structural assessment, periodic measurement of displacement, damage evaluation (e.g. crack width) and vibration characteristics are carried out with the sole objective of either detecting the changes that have taken place in the structure or where the structure appears to be at risk to plan for its evacuation (Hola and Schabowicz, 2005).
Some of the common methods that are employed in assessing the in-situ strength of concrete include Rebound Hammer Test (RHT), Ultrasonic Pulse Velocity Test (USPVT), Core Test (CT), Load Test (LT), Pullout Test (PT) and liquid Penetration Test (PnT). Although combination of two methods have also been used by some researchers. This is based on the fact that every method has its own limitation and hence using multiple methods will provide more reliable data for predicting the strength of a concrete (Huang et al., 2011).
To keep a high level of structural safety, durability and performance of the infrastructure in each country, an efficient system for early and regular structural assessment is urgently required. The quality assurance during and after the construction of new structures and after reconstruction processes and the characterization of material properties and damage as a function of time and environmental influences is more and more becoming a serious concern (Kristine and Nathaniel, 2014). Liquid penetration methods have a large potential to be part of such a system. Liquid penetration in general is widely used in several industry branches. Aircrafts, nuclear facilities, chemical plants, electronic devices and other safety critical installations are tested regularly with fast and reliable testing technologies (Mirmiran, 2021).
Non-destructive testing (NDT) is defined as the course of inspecting, testing, or evaluating materials, components or assemblies without destroying the serviceability of the part or system (Mirmiran, 2021).
The purpose of NDT is to determine the quality and integrity of materials, components or assemblies without affecting the ability to perform their intended functions. Non-destructiveness ought not to be confused with non-invasiveness (Miretti et al., 2014). Testing methods that do not affect the future usefulness of a part or system are considered to be non-destructive even if they consist of invasive actions. For example, coring is a common NDT method that is employed to extract and test specimens from concrete components in order to determine the properties of in-situ concrete. Coring alters the appearance of the component and marginally affects its structural integrity. If done correctly, coring maintains the serviceability of the structural component and is thus considered to be non-destructive (Helal et al., 2015).
A number of non-destructive tests are commonly performed for concrete members to determine the field strength and quality of concrete. Some of these tests are very useful in assessing the damage to RCC structures subjected to overloading, aging, corrosion, chemical attack etc. to check a high level of structural safety, durability and performance of the infrastructure in each country, an efficient system for early and regular structural assessment is urgently required in recent years. Innovative NDT methods, which can be used for the assessment of existing structures, have become available for concrete structures, but are still not established for regular inspections. The purpose of establishing standard procedures for liquid penetration of concrete structures is to qualify and quantify the material properties of in-situ concrete without intrusively examining the material properties. There are many techniques that are currently being researched for the liquid penetration of materials today (Kristine and Nathaniel, 2014).
Generally, at the time of construction, concrete cylinders are prepared to determine the concrete strength. It is often necessary to test concrete strength in a built RCC structures, which will help to determine whether the structure is suitable for its designed purpose. Such testing should be done without damaging the concrete. The test which is performed without damaging the concrete specimen is known as non-destructive test. Through those in which the concrete is partially damaged is known as semi-destructive test. Such as core cutting, where the structural member is repaired after the test. The crushing of the specimen is the usual destructive test to assess the strength of concrete.
In recent years, innovative liquid penetration, which can be used for the assessment of existing structures, have become available for concrete structures, but are still not established for regular inspections. Therefore, the objective of this project is to study the applicability, performance, availability, complexity and restrictions of liquid penetration.
The purpose of establishing standard procedures for liquid penetration of concrete structures is to qualify and quantify the material properties of in-situ concrete without intrusively examining the material properties (William et al., 2011). There are many techniques that are currently being research for the liquid penetration of materials today.
1.2 Statement of the problem
The goal in engineering investigative work is to determine the existing conditions of the structure in question and predict past and future conditions of the structure (Saleem et al., 2012). Besides that, every building needs to be evaluated for performance after the construction. Evaluation must be done periodically to detect any defects or failures that occur at the structure. Checking for deterioration after a period of service for a structure is compulsory in order to know the life of the building (Samia and Nacer, 2014).
By using liquid penetration there are many methods that can determine defect or failure that occur at the structure and every method have its own parameter. Furthermore, every single technique that always been use have their limited boundary which mean the method cannot afford an accurate and consistence result for different cases and to detect different defects (Vivien and Nataliya, 2011). Since there are many methods available for Non-Destructive Test at the moment there seems to be many arguments on the best Non-Destructive Test methods for evaluation (Baker, 2007). Thus, it is important for the research to carry out in turn to enhance the knowledge of liquid penetration for assessing structural integrity.
1.3 Significance/ rationale of the study
The main advantage of liquid penetration method is to avoid the concrete damage on the performance of building structural components. Additionally, their usage is simple and quick. Test results are available on site. Concrete testing in structures demanding in which the cores cannot be drilled, where the use of less expensive equipment is required.
The significant of the study is to examine structural integrity assessment using liquid penetration to determine any deterioration in the structure or any failure that can contribute into damaging. Other than that non-destructive test essentially refers to all the test methods which permit testing or inspection of material without impairing its future usefulness. Thus, non-destructive test methods are extremely valuable in assessing the condition of structures such as bridges buildings and highways.
Because of the current emphasis on rehabilitation and renovation of structures there is a critical need for the development of non-destructive methods that can be used to evaluate the condition of structures so that effective repair procedures can be undertaken. Other than that, the significant of this study is to propose which is the best method for structural evaluation. Basically, the purposes of the non-destructive test are to determine of material properties. Besides that, it also for detection characterization’s location and sizing of discontinuities or defects determine quality of manufacture or fabrication of a component or structure and lastly is for checking deterioration after a period of service for a component/structure. From all of the purpose of structural integrity assessment so it is important to learn about liquid penetration test and able to apply it as working as civil engineer.
1.4 Objectives of the study
The main objective of the study is to examine the structural integrity assessment using liquid penetration.
1.5 Specific objectives of the study
- To determine the strength of concrete using liquid penetration.
- To compare the strength found using liquid penetration.
- To establish a correlation among the strength found using liquid penetration.
1.6 Scope of the study
This study was carried out on the structural integrity assessment using liquid penetration. This study is restricted to structural designs of buildings and roads.