Rebound Hammer Test

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Rebound hammer test (Schmidt Hammer) is used to determine rapid compressive strength of concrete. Hammer consists of spring controlled mass slides on plunger. When the plunger of rebound hammer is pressed on surface of concrete, a spring controlled mass with a constant energy is made to hit concrete surface to rebound back. Rebound hammer is used to measures surface of hardness of concrete which is shown on given scale on rebound hammer. The scale shows rebound hammer and strength of concrete and hardness. Low strength and low stiffness concrete have low rebound value. Figure 4.10 Average Rebound Hammer Number 28 day Figure 4.11 Average Rebound Hammer Number 56 day 4.3.2 UPV Test Result The ultrasonic pulse velocity is used to determine…show more content…
In RCPT, include the amount of electrical current passes through cylindrical disc for six hour duration and result was taken at every 30 minutes interval. When total charge in coulombs passed, it shows the resistance capacity of chloride ion penetration. It is easy method to determine concrete permeability. It is not suitable method when there are too many design mix for evaluation durability of concrete, it may more time consuming. Charge is calculated from given equation. Q= 900(Io+2I30+2I60+……..+2I300+2I330+2I360) Figure 4.19 Average RCPT Coulombs Penetration 4.4.3 Sorptivity The sorptivity is determined to measure capillary rise absorption rate on concrete disc to check porosity of water rise up to 5 mm is allowable. Water was used of the test fluid. The cylinders after casting are cured in water for 28 days, 56 days and 90 days curing. The specimen size 100mm dia. x 50 mm height is casted, after drying and take weight of every 30 minutes interval up to 6 hour testing period, and flow from the peripheral surface is prevented by sealing it properly with non-absorbent coating with…show more content…
Steel corrosion process is very slow in laboratory performed test, which is help to determine long term durability of concrete at initial level and low curing period. If corrosion is very less it not required to cause structural damage. Results are obtained from current passes through the cylinder and steel is corroded, and weight is changes after the test is done. Corrosion of test is done and after the steel rod removed and weight is being taken and weight loss percentage of steel in sea water environment is checked. Figure 4.21 Accelerated Corrosion Weight loss in

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