Method for rapidly determining chloride ion permeation resistance of concrete

Abstract

The invention relates to a method for rapidly determining the chloride ion permeation resistance of concrete. The method comprises the following steps: slicing concrete, putting the obtained sliced concrete into a vacuum water-saturated device, pumping to a certain vacuum degree, injecting deionized water to the obtained vacuum chamber, and maintaining the vacuum degree for a certain period of time to make apertures in the concrete full of water; and carrying out alternating current impedance test of a test piece to obtain a characteristic conductivity, and calculating via a conversion formula to obtain an equivalent dielectric flux in order to evaluate the chloride ion permeation resistance of concrete. The method has the advantages of determination of the dielectric flux of concrete within a very short period of time, simplicity, reliable data, no less, and realization of multi-time test of the same test piece.

Description

technical field [0001] The invention relates to a method for quickly measuring the chloride ion permeability resistance of concrete, which belongs to the technical field of concrete. Background technique [0002] The intrusion of chloride ions is an important factor leading to steel corrosion and loss of durability in reinforced concrete structures. Existing methods for evaluating concrete’s resistance to chloride ion intrusion include: (1) electric flux method (namely American standard ASTM C1202, which is also a Chinese standard), (2) unsteady-state chloride ion migration method (Nordic standard NT Build492, The same is the Chinese standard), (3) steady-state chloride ion migration method (British "PERMIT" method), (4) conductivity method (NEL method). Among them, method (1) applies 60V direct current to the concrete test block with a thickness of 5 cm, measures the electric flux for 6 hours, and uses the electric flux value to characterize the chloride ion intrusion resi...

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Problems solved by technology

Among them, the method (1) applies 60V direct current to the concrete test block with a thickness of 5 cm, measures the electric flux for 6 hours, and uses the electric flux value to characterize the chloride ion intrusion resistance of the concrete. High, affecting the test results; method (2) Immerse the 5cm thick concrete test block in the sodium chloride solution, apply 10V~60V direct current on the electrodes at both ends of the test block, measure the depth of chloride ion intrusion into the concrete after a certain period of time, and calculate Obtaining the chloride ion diffusion coefficient has the advantages of wide applicability and reasonable method, but the disadvantage is that the test process is complicated and the test time is long; method (3) fasten the tester to the concrete surface, and the tester includes two separated inner and outer solution chambers , the solution chambers are respectively equipped with electrodes, and are filled with sodium chloride solution and deionized water respectively. After a certain voltage is applied, chloride ions enter the deionized water through the concrete surface under the action of an electric field, and the concrete is characterized by measuring the migration rate of chloride ions. The advantage of anti-chloride ion intrusion performance is that it can be applied to the engineering site, but the disadvantage is that the implementation is complicated and the test time is long; method (4) measures the conductivity of concrete by applying a branch voltage to the salt-saturated concrete test block, and characterizes the resistance of concrete to chloride ion intrusion Performance, its advantages are short test time and simple implementation, the disadvantage is that direct current can easily cause electrode polarization, resulting in deviations in test results

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