Abstract Based on the fracture mechanics concept, effects of specimen geometry on the tensile and compressive strength of magnetite-based heavyweight fly ash-based geopolymer concrete have been investigated both experimentally and analytically. In the experimental program, three mix designs have been prepared containing 0, 50, and 100% magnetite heavyweight aggregate (HWA) and were subjected to the fresh and 28-day mechanical properties tests. For that, 100 and 150 m m cubic specimen, and 100 × 200 and 150 × 300 m m cylindrical specimen for compressive strength measurement, cylindrical specimen with the same dimension as those for the compressive strength, for splitting tensile strength test, and 100 × 100 × 400 m m prism specimen for flexural strength were prepared. In the analytical section, by applying modified size effect law (MSEL) model and justifying its parameters for the heavyweight geopolymer concrete (HWGC), correlations between the compressive and tensile strengths of HWGC with the specimen geometry have been developed. In addition, correlation between the modulus of rupture (MOR) and compressive strength of HWGC was also established. The obtained results denoted the crucial role of the HWA in the fresh and mechanical properties of fly ash-based HWGC, alteration of the mechanical properties by varying the specimen geometry, and correlation between the MOR and compressive strength of fly ash-based HWGC.

中文翻译：

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重质地质聚合物混凝土的抗压和抗拉强度断裂模型

摘要 基于断裂力学的概念，试件几何形状对磁铁矿基重粉煤灰基地质聚合物混凝土抗拉和抗压强度的影响进行了实验和分析研究。在实验计划中，制备了三种混合设计，分别含有 0%、50% 和 100% 的磁铁矿重骨料 (HWA)，并进行了新鲜和 28 天的机械性能测试。为此，100 和 150 mm 立方试样，以及用于抗压强度测量的 100 × 200 和 150 × 300 mm 圆柱试样，与抗压强度相同尺寸的圆柱试样，用于劈裂拉伸强度试验，以及 100 × 100 ×制备用于抗弯强度的 400 mm 棱柱试样。在分析部分，通过应用修正的尺寸效应定律 (MSEL) 模型并证明其用于重质地质聚合物混凝土 (HWGC) 的参数，HWGC 的抗压强度和抗拉强度与试样几何形状之间的相关性得到了开发。此外，还建立了 HWGC 的断裂模量 (MOR) 和抗压强度之间的相关性。获得的结果表明 HWA 在粉煤灰基 HWGC 的新鲜和机械性能、通过改变试样几何形状改变机械性能以及 MOR 与粉煤灰基 HWGC 的抗压强度之间的相关性中的关键作用。还建立了 HWGC 的断裂模量 (MOR) 和抗压强度之间的相关性。获得的结果表明 HWA 在粉煤灰基 HWGC 的新鲜和机械性能、通过改变试样几何形状改变机械性能以及 MOR 与粉煤灰基 HWGC 的抗压强度之间的相关性中的关键作用。还建立了 HWGC 的断裂模量 (MOR) 和抗压强度之间的相关性。获得的结果表明 HWA 在粉煤灰基 HWGC 的新鲜和机械性能、通过改变试样几何形状改变机械性能以及 MOR 与粉煤灰基 HWGC 的抗压强度之间的相关性中的关键作用。