Development of predicting model of bending and compressive strength with maturity method in glass fiber reinforced concrete

Glassfiber Reinforced Concretes (GRC-CTB) have high mechanical and physical properties and are therefore being widely used in the construction industry. They can be produced as very thin shell elements as opposed to Portland cements and are more sustainable if environmental impacts are considered. In the design of shell elements, bending and tensile strength are preferred as the main criteria instead of the compressive strength. Monitoring the resting period of the concrete in the mould and dismantling the final product is crucial for the correct timing of the dismantling process. Destructive test methods and strength measures are not applicable in the decision of dismantling time especially if we are considering early age dismantling. Various methods exist for monitoring the development of early age strength. One of the nondestructive methods to estimate the development of concrete strength is the maturity method. This nondestructive method analyzes the joint effect of time and temperature on the material and it presumes that, the concrete which have the same mixture and the same maturity also have the same character. This method enables the monitoring the development of the concrete's strength in early ages with regard to environmental conditions and the control of demolding. In the literature we see that by using this method, the relationship between maturity and compressive strength is used to control all the parameters. In concrete that are reinforced with glass fibers, the critical strength value is the value of bending strength and not the value of compressive strength. In this study, our aim is to develop a model for the estimation of the maturity index method and the bending and compressive strength for glass fiber reinforced concrete. For this purpose, we have produced concrete with 1, 2, 3% glass fibers respectively. We have used the method of the Weighted Maturity Model to determine the C value for each type of cement. We have further produced more examples with these ratios. We have then placed warmth sensors in both the compressive and the bending models and measured the heat on the 1st, 2nd, 3rd, 5th, 7th, 14th, 28th and 56th days to calculate the values of their maturity indices. On the same days, we have measured the values of compressive and bending indices and density and Leeb hardness on concrete examples with different glass fiber ratios. We have then calculated and shown the maturity-compressive strength and the maturity-bending strength relations in cements with different glass fiber ratios by using the data we got from these experiments. As a result, we propose a new maturity-strength relationship model for glass fiber reinforced concrete.