The dynamic properties of a granite rock employed in crushed form as coarse aggregate in high-strength concrete, were experimentally characterised, and the average values obtained were assumed to be representative of the properties of the coarse aggregate. Cylindrical specimens were core-drilled from the granite rock, then cut into various lengths for different tests, i.e. static and dynamic uniaxial compression, as well as static and dynamic splitting tension (Brazilian tests). From the data obtained, the effects of strain rate on the mechanical properties (e.g. stress-strain relationship, tensile and compressive strengths) were analysed. Significant rate dependence was observed for both tensile and compressive responses, and this was quantified via a dynamic increase factor (DIF, the ratio between the dynamic and static strength). For compression, the DIF follows the CEB-FIP 2010 equation frequently used to describe the rate sensitivity of normal-strength concrete. The tensile response shows a stronger rate dependence than the compressive response, and its DIF deviates from predictions based on the CEB-FIP equation, which underestimates the tensile DIF, and defines a much higher strain rate at which transition from a gradual to a rapid increase in the DIF occurs. An empirical DIF formula, derived from fitting of experimental data, is proposed to describe the tensile rate sensitivity. Apart from experimental characterisation, efforts were also directed at identifying a constitutive model to describe the dynamic behaviour of the granite coarse aggregate, and the Johnson-Holmquist 2 (JH-2) model, commonly used to capture the impact response of brittle materials (e.g. rock, ceramic) was chosen. The dynamic tensile and compressive properties obtained from experiments, were employed to determine the material parameters in the JH-2 model. Finite element modelling of the dynamic compression and splitting tension tests was performed, using the JH-2 model and the material constants derived, to describe the behaviour of the granite specimen. The simulation results correlate well with experimental measurements.

以破碎形式用作高强度混凝土中的粗骨料的花岗岩岩石的动态特性通过实验表征，所获得的平均值被假定为代表粗骨料的特性。圆柱形试样从花岗岩岩芯上钻孔，然后切割成不同长度以进行不同的测试，即静态和动态单轴压缩，以及静态和动态劈裂拉伸（巴西测试）。根据获得的数据，分析了应变速率对机械性能（例如应力-应变关系、拉伸和压缩强度）的影响。拉伸和压缩响应都观察到显着的速率依赖性，这通过动态增加因子（DIF，动态和静态强度之间的比率）进行量化。对于压缩，DIF 遵循 CEB-FIP 2010 公式，常用于描述正常强度混凝土的速率敏感性。拉伸响应显示出比压缩响应更强的速率依赖性，其 DIF 偏离基于 CEB-FIP 方程的预测，该方程低估了拉伸 DIF，并定义了更高的应变速率，在该应变速率下从逐渐增加到快速增加在 DIF 中发生。提出了一个根据实验数据拟合得出的经验 DIF 公式来描述拉伸速率敏感性。除了实验表征外，还致力于确定一个本构模型来描述花岗岩粗骨料的动态行为，以及 Johnson-Holmquist 2 (JH-2) 模型，通常用于捕获脆性材料的冲击响应（例如岩石，陶瓷）被选中。从实验中获得的动态拉伸和压缩特性被用来确定 JH-2 模型中的材料参数。使用 JH-2 模型和导出的材料常数，对动态压缩和劈裂拉伸试验进行了有限元建模，以描述花岗岩试样的行为。模拟结果与实验测量结果很好地相关。