Experimental and numerical investigation of the impact resistance of fiber-reinforced concretes

In this thesis study, the effects of binder content, steel, polypropylene, and basalt fiber amounts on the mechanical and impact resistance properties of fiber-reinforced concrete were comprehensively investigated using experimental and statistical analysis methods. In the experimental study, 16 different concrete mixtures were prepared by using four levels of binder dosage and four levels of steel, polypropylene, and basalt fiber ratios. Optimization studies were conducted using the Taguchi L16 (4^4) orthogonal array to examine the parameters affecting the mechanical properties and impact resistance of fiber-reinforced concrete. As part of the experimental work, tests for both fresh and hardened mechanical properties of concrete samples were performed. Compression, flexural, and impact resistance tests were conducted on the concrete series. The experimental data obtained were subjected to Taguchi analysis to maximize the mechanical properties of the concrete, and optimal concrete mixtures were determined. The optimal mixtures were validated through experimental studies based on the Taguchi prediction results. Additionally, mechanical property predictions for 256 series of concrete mixtures were presented. Furthermore, the behavior of concrete samples under impact (single and multiple impact) was modeled using the ANSYS Exp. Dyn. module, and results consistent with experimental data were achieved. Advanced numerical analyses, including blast and projectile impact simulations, were conducted using the RHT (Riedel-Hiermaier-Thoma) material model to examine the damage models of concrete, reinforced concrete, and steel fiber-reinforced wall structures under dynamic effects. The results demonstrated that steel and synthetic fibers, with their optimal mixing ratios, provide an effective solution for improving the impact resistance of fiber-reinforced concrete. The experimental and numerical analysis results proved that fiber-reinforced concrete mixtures, by enhancing the energy absorption capacity and crack resistance under impact and collision effects, are a viable construction material for defense structures and other engineering applications requiring high impact resistance.