Following are the Methods of Repair for Dormant Cracks in Concrete: 1. Sealing of Cracks: Sealing of cracks as stand alone repair should be used in conditions where structural repair is not necessary. Isolated cracks whether extending through the concrete section or partially into it, should be sealed at the concrete surfaces. For this a (…)
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NEED AND TYPES OF INSPECTION OF CONCRETE STRUCTURES
NEED FOR INSPECTION OF CONCRETE STRUCTURES: Inspection is the first step towards any maintenance programme. The purpose of structural inspection can be classified as under: i) To provide assurance that the concrete structure is structurally safe and fit for it’s designed use. ii) To identify actual and potential sources of trouble at the earliest possible(…)
RECOMMENDED CONCRETE MIXES FOR VARIOUS CONSTRUCTION
RECOMMENDED CONCRETE MIXES FOR VARIOUS TYPES OF CONSTRUCTION WORKS: Type of work App. Concrete Mix Max. size of aggregates (mm) Water for one cement bag batch (ltr) Total for dry aggregates For aggregates condition from dry to moist Best consistency Small precast work, fence posts, poles, garden furniture and other work of very thin sections(…)
MEASURING REINFORCEMENT CORROSION IN CONCRETE
There is need to know the extent of corrosion in pre-stressing steel as well as that of reinforcing steel in concrete. No instrument / technique is available, at present, which can measure the extent of corrosion of steel. However, measurement of concrete properties, such as resistivity and potential of concrete can assess the probability of(…)
MEASURING LOSS OF PRESTRESS IN PRESTRESSED CONCRETE
Instruments for measuring loss of prestress in prestressed concrete: The initial pre-stressing force applied to the concrete element reduces due to elastic shortening of the concrete, anchorage losses, frictional losses etc. The pre-stressing force further reduces with the passage of time due to creep, shrinkage, temperature effect and relaxation of steel. The loss of pre-stressing(…)
MIX DESIGN OF HIGH STRENGTH CONCRETE
The properties of a high-strength concrete-mix with a compressive strength of more than 40 MPa is greatly influenced by the properties of aggregates in addition to that of the water-cement ratio. To achieve high strength, it is necessary to use lowest possible water-cement ratio, which invariably affects the workability of the mix and necessitates the(…)
REINFORCEMENT COVER MEASUREMENT USING MAGNETIC METHODS
Magnetic Method for Reinforcement Cover Measurement of Hardened Concrete Magnetic methods may be used to determine the location and cover to reinforcement embedded in hardened concrete. Some of the models commercially available in market are Micro-cover meter, Pachometer, Profometer, Fe-Depth meter, etc. These equipment are based on the principle that the presence Micro-Cover Meter of (…)
PURPOSE OF NON-DESTRUCTIVE TESTS ON CONCRETE STRUCTURES
NON DESTRUCTIVE EVALUATION OF CONCRETE STRUCTURES A variety of Non Destructive Testing (NDT) methods have been developed or are under development for investigating and evaluating concrete structures. These methods are aimed at estimation of strength and other properties; monitoring and assessing corrosion; measuring crack size and cover; assessing grout quality; detecting defects and identifying relatively(…)