Inspection of concrete structures in necessary to assess the building of damages, its strength, rehabilitation strategies, repair methods etc. to keep the structure safe.
Concrete Technology
Concrete Technology provides information on concrete and its properties, mix design, cracking, durability, high strength, prestressed concrete, precast concrete, fresh concrete ,hard concrete, Ready mix, SCC, special types of concrete, sulphate attack etc.
Deleterious Substances in Aggregate- Alkali-Aggregate Reactions
Deleterious Substances in Aggregate- Alkali-Aggregate Reactions Organic Impurities Organic impurities interfere with the hydration reaction Organic matter are mostly found in sand and consists usually of products of decay of vegetable matter (mainly tannic acid and its derivatives) Organic matter may removed from sand by washing To determine the organic content of aggregate, colorimetric test(…)
CONCRETE DURABILITY PROBLEMS
ENVIRONMENTAL-RELATED CAUSES OF CONCRETE DURABILITY PROBLEMS The inferior durability characteristics of concrete may be caused by the environment that the concrete is exposed to or by internal causes within the concrete. The following environmental conditions can affect the concrete durability: - Temperature - Moisture - Physical factors - Chemical factors - Biological factors(…)
MATERIALS FOR REPAIR OF CONCRETE STRUCTURES
The range of materials for repair of concrete structures to be effectively durable is fairly limited. The materials most widely used are concrete and mortar, which are made as far as practicable with the same type of cement and aggregates as were used in the original structure. When deterioration is due to chemical attack, it(…)
Concrete in Seawater
Concrete in Seawater For several reasons, effect of seawater on concrete deserves special attention. First, coastal and offshore sea structures are exposed to the simultaneous action of a number of physical and chemical deterioration processes, which provide an excellent opportunity to understand the complexity of concrete durability problems in practice. Second, oceans make up(…)
STAGES OF FRACTURE (CRACKING) IN CONCRETE
The stages of cracking (fracture) in concrete: There are three stages of cracking or fracture in concrete. When we describe the cracking mechanisms, it is important to differentiate between the mode of crack initiation and how this occurs at the microscopic level, and the subsequent paths of propagation and the eventual macroscopic crack pattern at(…)
Ready Mix Concrete-Batching, Mixing, Transporting, and Handling
Ready Mix Concrete-Batching, Mixing, Transporting, and Handling While Ordering Ready Mixed Concrete Following Points is to be specified: Coarse aggregate size Slump Air content Basis for proportioning, select Options A ,B, or C. Option A—performance based: Purchaser specifies: Compressive strength Concrete producer selects mix proportions. Option B—prescription based: Purchaser specifies mixture proportions including: · Cement(…)
Fresh Concrete
1. Quality of Concrete in affected by: Chemical composition of Portland Cement Hydration and development of the microstructure Admixtures Aggregate characteristics Placement Consolidation Curing 2. Alternatives to conventional concrete Lightweight, high-strength, polymer concrete, fiber-reinforced concrete, and roller compacted concrete Proportioning of Concrete Mixes Properties concerned with in the plastic state – Workability Finishing characteristics Properties(…)