Micromechanics of high-strength, high-ductility concrete
Micromechanics of high-strength, high-ductility concrete
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DOI：
10.14359/51685784
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
R. Ranade;V. Li;Stults;T. S. Rushing;J. Roth;W. Heard
中科院分区：
文献类型：
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作者：
R. Ranade;V. Li;Stults;T. S. Rushing;J. Roth;W. Heard
本文报道了一种新的纤维增强水泥基复合材料，高强度，高延性混凝土（HSHDC），它具有非常高的抗压强度（166 MPa [24.1 ksi]）和非常高的拉伸延性（3.4%应变能力）的罕见组合的微观调查。调查涉及的纤维/基体的相互作用性能，使用单纤维拔出试验的实验测定。发现了一种新的纤维拔出时随倾斜而变硬的机制，这是高强度水泥基材料所特有的。现有的应变硬化水泥基复合材料（SHCCs）的纤维拔出分析模型进行了修改，以纳入新的机制。将模拟的纤维拔出行为用于比例连接模型中，以计算HSHDC的裂纹桥接（σ-δ）关系，并通过单裂纹试验进行了经验验证。HSHDC的σ-δ关系满足基于细观力学的防止局部断裂的稳态平坦裂纹扩展的必要强度和能量条件。因此，在这项研究中的HSHDC的微观尺度调查，证明了合理的基础上，其设计相结合的高抗压强度和高拉伸延性。
This paper reports the microscale investigation of a new fiber-reinforced cementitious composite, high-strength, high-ductility concrete (HSHDC), which possesses a rare combination of very high compressive strength (166 MPa [24.1 ksi]) and very high tensile ductility (3.4% strain capacity). The investigation involved experimental determination of fiber/matrix interaction properties using single-fiber pullout tests. A new mechanism of inclination-dependent hardening in fiber pullout—unique for a high-strength cementitious matrix—is discovered. The existing fiber-pullout analytical model for strain-hardening cementitious composites (SHCCs) is modified to incorporate the new mechanism. The modeled fiber-pullout behavior is used in a scale-linking model to compute the crack bridging (σ-δ) relation of HSHDC, which is also empirically verified through single-crack tests. The σ-δ relation of HSHDC satisfies the micromechanics-based necessary strength and energy conditions of steady-state flat crack propagation that prevent localized fracture. The microscale investigation of HSHDC in this research thus demonstrates the rational basis for its design combining both high compressive strength and high tensile ductility.