Method for rapidly evaluating crack resistance of cement-based material

A technology of cement-based materials and anti-crack performance, which is applied in the field of building materials and can solve the problems of no evaluation method for the anti-crack performance of cement-based materials

Inactive Publication Date: 2012-07-04
福建省融旗建设工程有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] So far, there is still no general evaluation method for the crack resistance of cement-based materials at home and abroad.

Method used

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  • Method for rapidly evaluating crack resistance of cement-based material
  • Method for rapidly evaluating crack resistance of cement-based material
  • Method for rapidly evaluating crack resistance of cement-based material

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] 1. Test raw materials

[0035] P.O 42.5 cement (Fujian Taiwan Cement Plant), Minjiang river sand (medium sand), gravel (Tongkou gravel), fly ash (Huaneng Power Plant Class II fly ash), water reducer (Xiamen Hongfa Xianke Polycarboxylate superplasticizer produced by Chemical Building Materials Co., Ltd.), tap water.

[0036] 2. Concrete mix ratio

[0037] The designed concrete mix ratio is shown in Table 1.

[0038] Concrete mix ratio ( )

[0039]

[0040] 3. Test piece production

[0041] Adopt the method of patent CN1932512 to carry out mechanical performance and anti-crack performance test. According to the "Standards for Test Methods of Mechanical Properties of Ordinary Concrete" (GB / T50081-2002), standard specimens were prepared, and their 7d and 28d compressive strengths were tested. The test results are shown in Table 2.

[0042] Table 2 Concrete cube test results (MPa)

[0043]

[0044] . According to the collected strain of the inner steel ring...

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Abstract

The invention relates to a method for rapidly evaluating the crack resistance of the cement-based material, comprising the following steps: testing the crack resistance and the mechanical properties of the cement-based material to be evaluated, drawing an inner steel ring strain development curve which changes with time according to the obtained inner ring strain, calculating the circumferential tensile stress of the cement-based material, drawing a circumferential tensile stress curve which changes with time of the cement-based material, calculating the tensile strength which changes with time of the cement-based material according to the measured mechanical properties of the cement-based material, and evaluating the crack resistance of the cement-based material according to the circumferential tensile stress curve secant slope, the ratio of the circumferential tensile stress to the tensile strength of the cement-based material with the age of 14d and the ratio of the stress decrease value of the cement-based material at the first mutation age and in the first mutation period to the tensile strength of the cement-based material of the same age. The method is simple, practical, accurate and reliable. Due to the adoption of the method, the construction period of the building structure is not affected, the subsequent repair is avoided, the crack risk is reduced, the durability and the safety of the structure are improved, and the service life is prolonged.

Description

technical field [0001] The invention belongs to the technical field of building materials, and more specifically relates to a rapid evaluation method for crack resistance of cement-based materials. Background technique [0002] Cement-based materials, including concrete and mortar, are still indispensable and the most important building materials for civil engineering. However, cement-based materials also have defects, that is, they are prone to cracks. The main reason is that the tensile stress caused by the volumetric deformation of cement-based materials exceeds the tensile strength of the material. Once cracks appear in cement-based materials, regardless of the size of the cracks, it will accelerate the deterioration of the material. Taking concrete structures as an example, the appearance of cracks will cause harmful substances in the environment to directly reach the surface of steel bars, causing corrosion of steel bars, reducing structural bearing capacity, durabili...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N33/38G01N19/00
Inventor 季韬林旭健李思龙刘春苹代庭苇江其东
Owner 福建省融旗建设工程有限公司
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