Development of combined methods to estimate in-place strength of high strength concrete using non-destructive testing

High strength concrete (HSC) is a special type of concrete with an average compressive strength of 50 MPa and above. This type of concrete has high strength and durability, and has a high compact structure. With the development of material technology, interest in HSC production has gradually increased. The aim of this thesis is to develop double and triple combined methods, which are not included in the literature, by using non-destructive testing methods to effectively determine the in-place compressive strength of high strength concretes (HSC). For this purpose, HSCs with different mixing ratios were produced and concrete samples were obtained. The producted specimens, for non-destructive test methods; Schmidt concrete test hammer, ultrasound transmission rate, penetration resistance and maturity were tested using. The data obtained from the test results were analyzed via the statistical method called the response surface method and a separate mathematical model was developed for each combined method applied. It is aimed to contribute to the literature by determining the conditions in which each of the models can be used effectively in practice. As a result, the data obtained with the help of non-destructive testing methods enabled the concrete compressive strength to be estimated in-place and effectively by using the mathematical model of the related combined method. The developed mathematical model was compared with non-destructive testing methods and its accuracy and applicability were checked. Thus, by estimating the concrete compressive strength with high accuracy, it will be possible to realize the project durations at the desired time. It is foreseen that this will provide great advantages in terms of time, cost and labor. In addition, it is aimed to make a new contribution to the literature with the mathematical model to be developed and to lead the studies to be carried out on this subject.