In this study, the expansion behavior, surface and internal crack developments due to the alkali–silica reaction in two types of reinforced concrete prisms with and without stirrups are investigated. Longitudinal and transverse expansions are continuously monitored at various positions on the prism surfaces. Image analysis is employed to determine the densities of surface and internal cracks. Crack orientations for several groups of crack angles are measured to characterize the dominant crack pattern. The findings indicate that longitudinal expansion was transferred to the transverse direction at the middle region in both prisms, regardless of the presence of stirrups. However, average longitudinal, transverse, and volumetric expansions are reduced in prisms with stirrups. The anisotropy coefficient of expansion exhibits a strong proportional relationship with the surface and internal crack densities of each crack angle group. Therefore, the trend of internal crack orientations and expansion anisotropy can be estimated based on surface crack information.

中文翻译：

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碱硅反应引起的钢筋混凝土各向异性膨胀行为和裂纹方向


在本研究中，研究了带箍筋和不带箍筋的两种类型的钢筋混凝土棱柱中由于碱硅反应而导致的膨胀行为、表面和内部裂纹的发展。在棱镜表面的不同位置连续监测纵向和横向膨胀。采用图像分析来确定表面和内部裂纹的密度。测量几组裂纹角度的裂纹方向来表征主要裂纹模式。研究结果表明，无论是否存在箍筋，两个棱柱的纵向膨胀都会转移到中间区域的横向方向。然而，带箍筋的棱柱的平均纵向、横向和体积膨胀会减小。各向异性膨胀系数与每个裂纹角组的表面和内部裂纹密度呈现出很强的比例关系。因此，可以根据表面裂纹信息来估计内部裂纹方向和扩展各向异性的趋势。