In this paper, concrete mixes utilizing two sizes of natural aggregate and two sources of lightweight and recycled aggregates were used to investigate the effect of aggregate type and specimen size and shape on the compressive strength of concrete. In addition, samples from ready-mix concrete producers with different strengths were evaluated using standard size cylinders and cubes. Results were obtained on the 7th, 28th, and 90th day. In addition, flexural strength, split tension, and modulus of elasticity were evaluated on the 28th and 90th day. Statistical analyses were conducted to examine the significance of the difference between the compressive strength values for each two mixes using tests of hypotheses. Moreover, other mechanical properties as a function of compressive strength were discussed and compared to those predicated by the American Concrete Institute (ACI) specifications. Results indicate specimen shape has a noticeable effect on the compressive strength as the Cylinder/Cube ratio on the 90^th day was ranging between 0.781 and 0.929. The concrete compressive strength and modulus of elasticity were significantly affected by the aggregate type. The flexural strength and split tensile strength were less affected by the aggregate type, which was also confirmed by the values predicted with the ACI equations.

中文翻译：

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骨料类型和试样形态对混凝土抗压强度的影响

在本文中，使用两种尺寸的天然骨料和两种轻质和再生骨料来源的混凝土混合料来研究骨料类型，试样尺寸和形状对混凝土抗压强度的影响。此外，使用标准尺寸的圆柱体和立方体对来自不同强度预拌混凝土生产商的样品进行了评估。在第7、28和90天获得结果。另外，在第28天和第90天评估了挠曲强度，劈裂张力和弹性模量。进行统计分析以使用假设检验检验每两种混合物的抗压强度值之间差异的显着性。此外，讨论了作为抗压强度的函数的其他机械性能，并将其与美国混凝土协会（ACI）规范预测的性能进行了比较。结果表明，试样的形状对压缩强度有显着影响，因为圆柱/立方比在90^第一天在0.781至0.929之间。骨料类型显着影响混凝土的抗压强度和弹性模量。抗弯强度和劈裂抗拉强度受集料类型的影响较小，这也由ACI方程预测的值证实。