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(…)
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(…)
Retrofitting of RCC structural members is necessary to prevent further distress in concrete. The retrofitting of RCC members should start with investigation and diagnosis of cracks and then by applying suitable retrofitting measures. Following are the steps involved in this process: 1. Investigation and diagnosis of cracks: (i) After the appearance of cracks in RCC(…)
Distress in concrete members occurs with age due to corrosion in reinforcement, loading, settlement of foundations etc. This distress in in building can be found by development of cracks in concrete members such as slabs, beams, columns etc. The cracking of concrete in building is developed in three stages: 1. Stage – I: Volume of(…)
Protection systems of joints include the sealing of cracks, contraction (control) joints, expansion joints, and construction joints. Joint sealants in concrete minimize the intrusion of liquids, solids, or gases, and protect the concrete against damage.
Plastic settlement cracks form within 30 minutes to 6 hours of casting the concrete, dependent on the prevailing conditions and mix characteristics. The mechanism of plastic settlement If the settlement of solids in the concrete can freely take place without hindrance there will be a reduction in depth and volume of the cast concrete but(…)
Poor construction methods and workmanship is responsible for the failure of buildings and structure. The poor construction methods and workmanship is caused due to negligence and inadequate quality control at construction site. The effects of some of the poor construction methods are discussed below: (a) Incorrect placement of steel Incorrect placement of steel can result(…)
Causes of defects in concrete structures can be broadly categorized as: i) Structural deficiency resulting from errors in design, loading criteria, unexpected overloading, etc. ii) Structural deficiency due to construction defects. iii) Damage due to fire, floods, earthquakes, cyclones etc. iv) Damage due to chemical attack. v) Damage due to marine environments. vi) Damage due(…)
Damage to structural concrete can be due to the use of excessive water, poor cement, poor construction practices, improper mixture proportioning, dirty or low quality aggregate, and inadequate curing.