Concrete Repair, Rehabilitation - Essay Example

There are some published works concerning the influence of roughness and moisture properties of the substrate surface on the bond strength with added layer. But, most works concentrate only on one characteristic of roughness or moisture or test method etc., at one time. Further, roughness is assessed only qualitatively, by observing the substrate surface and by classifying it as very smooth, smooth, rough. In the Eurocode 2 (Eurocode 2, 2003) it is stated that for shear at interface between concrete cast at different times, "in the absence of more detailed information, surfaces may be classified as very smooth, smooth, rough or indented".

This kind of roughness evaluation has disadvantage due to subjective results. Thus, this dissertation aims to carry out an experimental study for evaluating the effect of different surface conditions on the bond between two concretes and to compare the effects of different roughness conditions relative to quantified roughness parameters. It is anticipated that with this study, a suitable condition for substrate surface for optimum bond will be established. The researcher wishes to convey his profound gratitude and sincerest appreciation to those who have extended much effort and assistance contributory to the success of the dissertation.

His deepest indebtedness goes particularly to the following: Almighty God, for giving him strength, wisdom, and vision to finish his study; His Supervisor, for his guidance and suggestions to improve the research work;His family, who reassured, inspired, and supported him morally, and financially; His colleague and friends, for their words of encouragement; All others who helped the researcher make this dissertation possible. TABLE OF CONTENTSTitle Page Abstract Acknowledgment Table of Contents List of Figures CHAPTER 1 - IntroductionGeneralAdhesionLiterature ReviewCHAPTER 2 - MethodologyTest MethodsShear TestsDirect Shear Test CHAPTER 3 - Experimental DetailsConcrete Mix PropertiesSample DetailsTest DetailsCHAPTER 4 - Results & DiscussionsCHAPTER 5 - Conclusions & RecommendationsLIST OF FIGURESCHAPTER 1INTRODUCTIONConcrete remains an indispensable construction material because of its flexibility, durability and workability.

With time, however, concrete structures deteriorate and weaken, thus repair and restructuring is inevitable. Signs of deterioration or defects such as cracks on the structures are often perceived as indicators of the need to perform maintenance. Concrete repairs usually require adding of new concrete to existing old concrete element to protract the 'useful life of an existing structure, to restore its load-carrying capacity and stiffness, and to strengthen its members' (Bissonnette, et al., 2009).

Some of the most commonly used cementing materials in the production of the new overlay include resin, mortar, mortar purified with latex, ordinary concrete (OC),