Evaluation method of freezing resistance of concrete

An evaluation method and concrete technology, which are applied in the preparation of test samples, measuring devices, instruments, etc., can solve problems such as the inability to accurately reflect the level of concrete frost resistance, and achieve the effect of high accuracy and wide application prospects.

Inactive Publication Date: 2017-03-22
HOHAI UNIV
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Problems solved by technology

[0003] Technical problem to be solved: the present invention is to solve the technical problem that neither the existing fast freezing method nor the slow freezing method can accurately reflect the freezing-thawing cycle number and the freezing-thawi

Method used

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  • Evaluation method of freezing resistance of concrete
  • Evaluation method of freezing resistance of concrete
  • Evaluation method of freezing resistance of concrete

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0027] Ordinary Portland cement of P.O42.5 grade is used to configure concrete with a strength grade of C20, and a concrete specimen of 100mm*100mm*400mm is formed, and it is cured for 28 days at 20°C and 95% humidity for standby; the curing specimens are grouped, Put it into a freeze-thaw device with antifreeze as the freeze-thaw medium, and conduct freeze-thaw cycle experiments of 50 times, 100 times, 150 times and 200 times respectively. The time was 4 hours, 8 hours, and 16 hours respectively. Considering the combination of the above conditions, a total of 12 sets of freeze-thaw cycle experiments were carried out. Measure the relative dynamic elastic modulus of 12 groups of test pieces, and calculate according to the following formula:

[0028]

[0029] Where: f ini is the transverse fundamental frequency of the concrete specimen before the freeze-thaw cycle, and f(n,t) is the transverse fundamental frequency of the concrete specimen with n freeze-thaw cycles a...

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Abstract

The invention provides an evaluation method of freezing resistance of concrete. The method establishes a freezing resistance evaluating indicator relative dynamic elastic modulus evaluation model P(n,t)=(1-kn)[1-alpha<t-4>beta], wherein n is the freezing-thawing circulation frequency; t is single-time freezing-thawing circulation time; k represents the coefficient related to freezing-thawing circulation frequency; and alpha and beta represent the coefficients related to freezing-thawing circulation time. The evaluation model can reflect the concrete freezing resistance level under the combined actions of different freezing-thawing circulation frequencies and different freezing-thawing circulation times, is simple and easy to use and high in accuracy, and has wide application prospects.

Description

technical field [0001] The invention belongs to the technical field of concrete material / structure safety, and specifically evaluates the frost resistance performance of concrete by establishing the expression of the relative dynamic elastic modulus of the frost resistance evaluation index. Background technique [0002] Concrete has been widely used in civil engineering because of its rich raw materials, superior construction performance, economical and practical characteristics. At present, there are many methods used to evaluate the frost resistance performance of concrete materials in the field of civil engineering, mainly the quick freezing method and the slow freezing method. It is difficult to calculate and consider the concrete frost resistance performance level under the combined effect of the number of freeze-thaw cycles and the freeze-thaw cycle time in the actual engineering environment. Contents of the invention [0003] Technical problem to be solved: the pre...

Claims

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Application Information

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IPC IPC(8): G01N33/38G01N1/28
CPCG01N1/28G01N33/383
Inventor 卞瑞张研蒋林华
Owner HOHAI UNIV
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