In order to understand the impregnation mechanism of a yarn by a cementitious matrix and its influence on the mechanical properties of a yarn/cement composite, pull-out tests have been performed on samples of yarn/cement. Two embedded lengths for the yarn and different rheological and mechanical properties for the matrix were tested. Two pull-out modes were distinguished according to the compressive strength of matrices. For matrices with a compressive strength between 60 and 70 MPa the pull-out mode is characterized by a behaviour close to the tensile behaviour of the yarn, with maximum load values reaching approximately 60% of the tensile maximum load because of filaments damages. For matrices with compressive strength inferior to 60 MPa, the pull-out mode exhibits a residual phase linked to a slippage and an extraction of a variable number of filaments, with lower maximum load values than the first pull-out mode. After pull-out test, for some samples with filaments extraction, an innovative method based on a double impregnation with resin enables to visualize the yarn/matrix interface and identify the level of impregnation of the filaments by using confocal microscopy. It is concluded that this level of impregnation has a direct influence on the mechanical behaviour of the embedded yarn, except for the slippage and extraction phase, but the rheological properties of the matrix has no significant influence on this impregnation.

中文翻译：

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嵌入水泥基体的复丝纱线拉拔试验研究

为了了解水泥基体对纱线的浸渍机制及其对纱线/水泥复合材料机械性能的影响，对纱线/水泥样品进行了拉拔试验。测试了纱线的两种嵌入长度以及基体的不同流变学和机械性能。根据基体的抗压强度区分两种拔出模式。对于抗压强度在 60 到 70 MPa 之间的基体，拉出模式的特征在于其行为接近纱线的拉伸行为，由于长丝损坏，最大载荷值达到拉伸最大载荷的大约 60%。对于抗压强度低于 60 MPa 的基体，拉出模式显示出与滑动和提取可变数量长丝相关的残余阶段，其最大负载值低于第一拉出模式。拉拔测试后，对于一些长丝提取的样品，一种基于树脂双重浸渍的创新方法可以通过共聚焦显微镜观察纱线/基质界面并识别长丝的浸渍水平。得出的结论是，这种浸渍水平对嵌入纱线的机械性能有直接影响，除了滑移和萃取阶段，但基体的流变特性对这种浸渍没有显着影响。一种基于树脂双重浸渍的创新方法，可以通过共聚焦显微镜观察纱线/基质界面并识别长丝的浸渍水平。得出的结论是，这种浸渍水平对嵌入纱线的机械性能有直接影响，除了滑移和萃取阶段，但基体的流变特性对这种浸渍没有显着影响。一种基于树脂双重浸渍的创新方法，可以通过共聚焦显微镜观察纱线/基质界面并识别长丝的浸渍水平。得出的结论是，这种浸渍水平对嵌入纱线的机械性能有直接影响，除了滑移和萃取阶段，但基体的流变特性对这种浸渍没有显着影响。