Durability Assessment of Concrete Structures due to various Chemical attacks

The strength and durability of concrete after casting can vary due to various factors, including physical and chemical damages. Concrete structures reinforced with steel are subject to continuous deterioration due to corrosion caused by long-term exposure to aggressive environments. Structures such as dams, canals, and bridges, which are exposed to water, undergo various types of chemical reactions including carbonation attack, sulphate attack, chloride attack, and alkali-aggregate reaction. These chemical reactions, whether intrinsic or extrinsic, are major contributors to concrete deterioration. This dissertation analyzes chemical expansive reactions in concrete elements, alkali aggregate reactions, and internal sulfuric reactions. During the carbonation process, calcite is a fundamental element identified in the concrete microstructure, often appearing as cracks on the surface of concrete structures. Carbonation occurs when carbon dioxide from the environment reacts with calcium hydroxide to form calcium carbonate. The depth of carbonation, usually described by pH value, directly affects the lifespan of the structure. To address this issue over the years, solutions have been discovered through various experiments conducted on concrete both before and after casting. These solutions include chemical tests to increase CO2 binding capacity and improve CaO value, as well as physical tests such as applying epoxy coatings, among others. After conducting various tests to achieve specific outcomes, durability tests for concrete structures are performed, including pH indicator tests, Universal Testing Machine (UTM) tests, and Compressive Testing Machine (CTM) tests. This project aims to study the chemical reactions occurring in various types of concrete structures and their impact on durability and strength.