In this study, various rock and cementitious rock-like material specimens with same ratio of length to diameter and different sizes were tested under various deformation controlled loading rate (mm/min) and load controlled rate (kN/s) conditions. According to the results obtained from 93 specimens of 5 different types of rock material and 2 different rock-like materials (cement paste and a concrete mix including sand) tested in this study, uniaxial compressive strength (UCS) values were found to significantly decrease with an increase in the specimen size under the condition of a load controlled rate (kN/s) selection. To practically remove the size effect on UCS values, the uniaxial compression test is suggested to perform selecting the loading rate as strain controlled (s⁻¹) and proportional to diameters of specimens with different sizes and same geometry. In addition to the UCS values, Modulus of elasticity values, stress and strain graph shapes and deformation characteristics were found to significantly change with the change of the specimen size and loading rate. According to the results, both modulus of elasticity values and brittleness were found to notably increase as a result of increase in loading rate values.

中文翻译：

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加载速率条件和试样尺寸对单轴压缩下岩石材料强度和变形性的影响

在这项研究中，在不同的变形控制加载速率（mm / min）和加载控制速率（kN / s）条件下，测试了具有相同的长径比和不同尺寸的各种岩石和胶结岩石样材料。根据从本研究中测试的5种不同类型的岩石材料和2种不同的类岩石材料（水泥浆和含沙的混凝土混合物）的93个样本获得的结果，发现单轴抗压强度（UCS）值随在选择负荷控制速率（kN / s）的条件下增加样本尺寸。为了切实消除尺寸对UCS值的影响，建议进行单轴压缩试验以选择加载速率作为应变控制（s ^-1）并与具有不同尺寸和相同几何形状的标本的直径成比例。除UCS值外，还发现弹性模量，应力和应变图的形状以及变形特性会随着试样尺寸和加载速率的变化而显着变化。根据该结果，发现弹性模量值和脆性均由于加载速率值的增加而显着增加。