The Experimental Study On The After Bonded Rebars Method To Test The Strength Of Concrete

The concrete as one of the most important materials in the current construction,has been widely used from the date of birth. It is an important task for construction toinspect and guarantee the quality of the concrete. At present the commonly used inour country is rebound method、ultrasonic method、ultrasonic-rebound method、coredrilling method、pull-out method and so on, but they all have their own defects, thebiggest drawback of the rebound method which is the most widely used in theengineering is that it does not apply to concrete slab. This article mainly aims at theshortage of the pull-out method, the preembeding pull-out method can not test thestrength of concrete anytime or anywhere, and it is difficult for afterinstalling methodto groove. Then puts forward the after bonded rebars method based on theimprovement of the pull-out method, makes the anchoring parts together with theconcrete by the inserted bar glue which has enough strength, which will produce thedestruction of concrete itself rather than the inserted bar glue. This article is based on《The Standard for Test Method of Mechanical Properties on Ordinary Concrete》(GB/T50081-2002), and 《Technical Specification for Inspection of ConcreteCompressive Strength by rebound Method》（JGJ/T23-2011）,refers to 《The TechnicalRegulation for Afterinstalling Method To Test Strength Of Concrete》(CECS69：94).The following researches are carried out:1. First of all, it puts forward the after bonded rebars method, which can solvethe problem that the rebound method does not apply to test the concrete slab inJGJ/T23-2011.2.It uses the waste concrete in laboratory to test the after bonded rebars method,then determines the various parameters of the method, such as anchoring piece ofdiameter、the anchoring depth、the mixing ratio of glue. It should choose the mostreasonable parameters to achieve the perfect experiment effect.3. Four concrete slabs have been poured in the laboratory, the size is2000mm×800mm×80mm, a series of after bonded rebars method has carried out onthem, and it is supplemented by compressive strength test. then describes the testphenomenon, calculates and analyses the test data, at last establishes the formula forthe after bonded rebars method.Its related parameters meet the requirement ofrelevant regulations, that suggests it has good relationship between the pull-out forceand concrete compressive strength. 4. It adopts Mohr-Coulomb criterion to analysis the limit state of pull-out method,deduces the theoretical formula.the relative error between the theoretical formulaand the formula of after bonded rebars method is9.97%.then uses the ANSYS tomake numerical analysis, reveals the force condition of concrete in the process ofthe test, summarizes the failure mechanism of the after bonded rebars method, that isthe concrete in the test is mainly tension failure under the action of pull-out force.5. At last it analyses the influencing factors concerning the after bonded rebarsmethod, such as coarse aggregate、carbonation depth、age of concrete、error ofembedded depth and so on, suggests the error of embedded depth should get moreattention.