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<p>Engineering cementitious composites (ECC) are known for their ductility and notch resistance under dynamic loading. However, the impact resistance of ECC with pre-existing notches remains underexplored, especially in critical structural applications. Existing studies mainly focus on unnotched or randomly notched specimens, lacking systematic analysis of notch length and depth configurations aligned with the impactor. This study examines the impact resistance of ECC incorporating a range of notch configurations under drop-weight loading conditions. A total of seventeen distinct notch types were introduced, including central, side, two notches, three notches, short-edge, long-edge, and both short and long interior notches. Each notch was fabricated with depths of 15&#xa0;mm, 30&#xa0;mm, and 45&#xa0;mm, and a uniform width of 2&#xa0;mm. All notches were positioned on the top surface of the specimen during testing, with the impact load applied directly at these locations. The impact strength of ECC was evaluated using the drop-weight impact test in accordance with ACI Committee 544 guidelines. In addition, all ECC specimens were reinforced with 2% polypropylene fibers by volume. This novel specimen arrangement represents a significant advancement in the current research trends. In addition, the two least square Weibull distribution analysis was performed to analysis the scattered results. The results demonstrate that the specimen featuring a 30&#xa0;mm-deep edge-aligned notch with a length of 50&#xa0;mm, exhibited the highest impact number causing failure (H2) among all notched configurations, with a marginal reduction of only 2.23% compared to the unnotched control specimen. The second-highest H2 value was observed in specimen incorporating a 15&#xa0;mm-deep notch positioned 25&#xa0;mm from the longitudinal centerline, which resulted in a slight decrease of 4.58%. These results indicate that notches of limited depth or those located near the specimen edges exert minimal adverse effects on the residual impact energy of ECC. Conversely, specimens with greater notch depths demonstrated markedly lower H2 values. Specifically, specimens with central notch, single notch at 25&#xa0;mm from center, and two full-length notches at 25&#xa0;mm from center recorded H2 of 125, 148, and 103, respectively, reflecting reductions of 52.29%, 43.51%, and 60.69% relative to the control (no-notch). These significant declines in post-crack energy absorption are primarily attributed to elevated stress concentrations and the associated reduction in effective cross-sectional area induced by increased notch depth, thereby emphasizing its detrimental influence on the toughness characteristics of ECC subjected to impact loading. </p>

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Effect of notch configurations on impact response of engineering cementitious composites

  • 期刊论文

  • 发表日期：

    2025年7月15日

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  • Sallal R. Abid,
  • G. Murali,
  • Ahmmad A. Abbass,
  • Sajjad H. Ali

摘要

Engineering cementitious composites (ECC) are known for their ductility and notch resistance under dynamic loading. However, the impact resistance of ECC with pre-existing notches remains underexplored, especially in critical structural applications. Existing studies mainly focus on unnotched or randomly notched specimens, lacking systematic analysis of notch length and depth configurations aligned with the impactor. This study examines the impact resistance of ECC incorporating a range of notch configurations under drop-weight loading conditions. A total of seventeen distinct notch types were introduced, including central, side, two notches, three notches, short-edge, long-edge, and both short and long interior notches. Each notch was fabricated with depths of 15 mm, 30 mm, and 45 mm, and a uniform width of 2 mm. All notches were positioned on the top surface of the specimen during testing, with the impact load applied directly at these locations. The impact strength of ECC was evaluated using the drop-weight impact test in accordance with ACI Committee 544 guidelines. In addition, all ECC specimens were reinforced with 2% polypropylene fibers by volume. This novel specimen arrangement represents a significant advancement in the current research trends. In addition, the two least square Weibull distribution analysis was performed to analysis the scattered results. The results demonstrate that the specimen featuring a 30 mm-deep edge-aligned notch with a length of 50 mm, exhibited the highest impact number causing failure (H2) among all notched configurations, with a marginal reduction of only 2.23% compared to the unnotched control specimen. The second-highest H2 value was observed in specimen incorporating a 15 mm-deep notch positioned 25 mm from the longitudinal centerline, which resulted in a slight decrease of 4.58%. These results indicate that notches of limited depth or those located near the specimen edges exert minimal adverse effects on the residual impact energy of ECC. Conversely, specimens with greater notch depths demonstrated markedly lower H2 values. Specifically, specimens with central notch, single notch at 25 mm from center, and two full-length notches at 25 mm from center recorded H2 of 125, 148, and 103, respectively, reflecting reductions of 52.29%, 43.51%, and 60.69% relative to the control (no-notch). These significant declines in post-crack energy absorption are primarily attributed to elevated stress concentrations and the associated reduction in effective cross-sectional area induced by increased notch depth, thereby emphasizing its detrimental influence on the toughness characteristics of ECC subjected to impact loading.