Experimental Study On The Dynamic Bending Properties Of The Concrete Under The Classification Sustained Load

Concrete is one of the most useful building material.In modern structures and buildings, the role of the concrete is more and more critical.Not only static load but also dynamic load works on the concrete structures.In recent years,the research results in the static mechanical performances of concrete have been greatly improved. However, there are more work to do in the research results of the dynamic mechanical properties,especially including changes of the concrete dynamic bending tensile performance in the experience of loading history. So,in the experience of loading history, it is very important to do the research of the dynamic mechanical properties.In this paper,there is a series of dynamic bending tensile test on the C40,C45,C50 concrete specimens on the basis of summarizing the previous research results, using the MTS loading devices and advanced data acquisition instrument, adopting the appropriate methods of making specimen and loading process. The dynamic bending tensile experiment was carried out using different strain rates, such as 10-6/s、10-5/s、10-4/s Strain rates and graded loading make a large impact on dynamic bending tensile performance and deformation performance of the concrete, including the flexural mechanical properties and deformation properties(flexural strength, elastic modulus, Poisson’s ratio, peak strain). After analysising the process and results of the test, the bending tensile failure mechanism of concrete can be found.According to the experimental results, with the increase of the initial load, flexural tensile strength, elastic modulus of concrete are in reduce and peak value of the stress strain curve is in growth trend under certain conditions of strain rate. With the increase of strain rates, the flexural tensile strength of concrete is also improved under certain conditions of graded sustained loads.While,elastic stage of poisson’s ratio is about 0.2.