Experimental and numerical investigation on dynamic mechanical properties of geopolymer-based ultra-high performance concrete (G-UHPC)

Geopolymer-based Ultra-High Performance Concrete (G-UHPC) shows promising potential for impact-resistant structures due to its excellent mechanical properties and environmental benefits. This study systematically investigates the dynamic mechanical behavior of G-UHPC under compression and splitting tensile loading using a Split Hopkinson Pressure Bar (SHPB) system. Combined with Digital Image Correlation (DIC) technology, full-field strain evolution was captured to reveal the dynamic damage mechanisms. Experimental results demonstrate that G-UHPC exhibits significant strain rate dependence, with dynamic compressive strength and energy absorption capacity increasing notably with strain rate. The dynamic splitting tensile strength also improves with increasing strain rate, while the failure mode transitions from single-crack to multiple-crack network development. Furthermore, a finite element model of G-UHPC was established based on the K&C concrete constitutive model, showing good agreement with experimental data and validating the model’s effectiveness. Through numerical simulations extending the strain rate range, quantitative relationships were established among the Dynamic Increase Factor (DIF), crack density, and strain rate, revealing the damage evolution characteristics of G-UHPC under high strain rates. This research provides crucial experimental data and numerical support for engineering applications and numerical analysis of G-UHPC under impact loading.