Research For Testing Curve Of Detecting The Concrete Compressive Strength By Rebound Method In Henan Area

Concrete structure occupies a leading position in the current construction project.The control of the concrete quality becomes more and more important in the actual project because the concrete quality problem occurs frequently.The concrete strength is one of the key factors in the quality control of concrete,whether it is the acceptance of new buildings or existing buildings assessment and improvement,strength evaluation of concrete structures are involved.Inspection of concrete compressive strength by rebound method is one of the basic methods of non destructive testing technology,has been widely used in the engineering testing.At present,the strength curve used by rebound method in Henan area is the unified strength curve of the industry standard.However,with the use of mineral admixture and strength development of concrete structure.Unified strength test curve occur some limitations in practical application process.In this thesis,according to the actual production process level of concrete in Henan area,the experimental study on the rebound strength curve is carried out,which is starting from engineering practice and in strict accordance with the requirements of establishing regional strength curve of current national regulations.The main research contents and results are as follows:1.On the basis of summarizing the domestic and foreign research on the influence of rebound method,this paper mainly analyzes the influencing factors of the rebound strength curve from the aspects of hammer,test method and concrete material.By analyzing the influence of various factors on the strength of concrete and the value of rebound value,the test scheme for determining compressive strength of concrete by rebound method is determined.2.The rebound test is carried out with momentum rebound hammer.At the same time,the production of concrete test pieces is carried out by using the concrete material,the forming process and the curing condition commonly used in the Henan area.The least squares method was used to analyze the test data in different types offunctional models.Through the comparison of precision and error,the strength curve of concrete strength in the area of 10 ~ 70 MPa is obtained3.Based on the comparison of the regional strength curve and the national unified strength curve.The results show that the relative error of national uniformity curve is relatively large in Henan area,and the accuracy of the regional intensity curve is obviously improved,which is more suitable with the actual application of the regional rebound method to estimate the concrete compressive strength.Through the experimental study in this thesis,we can get the strength curve of concrete strength test in Henan area.The effective range of the curve is 10 MPa ~70MPa,which is higher than that of the current national standard.The range of the measured strength is improved and the accuracy of the estimation is also improved.It can provide an important basis for the development of the curve of the resilience of the province.At the same time,it can provide reference for improving the non-breaking detection technology level in Henan province.