Li Lufan, Xia Jun, Chin Chee, Jones Steve
Department of Civil Engineering, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China.
Institute for Sustainable Material and Environment, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China.
Materials (Basel). 2020 Nov 10;13(22):5064. doi: 10.3390/ma13225064.
Ultra-high performance fibre reinforced concrete (UHPFRC) is an innovative cement-based engineering material. The mechanical properties of UHPFRC not only depend on the properties of the concrete matrix and fibres, but also depend on the interaction between these two components. The fibre distribution is affected by many factors and previous researchers had developed different approaches to test the fibre distribution. This research adopted the non-destructive C-shape ferromagnetic probe inductive test and investigated the straight steel fibre distribution of the UHPFRC plate. A simplified characterization equation is introduced with an attenuation factor to consider the different plate thicknesses. The effective testing depth of this probe was tested to be 24 mm. By applying this method, fibre volume content and the fibre orientation angle can be calibrated for the entire plate. The fibre volume content generally fulfilled the design requirement. The fibre orientation angle followed a normal distribution, with a mean value of 45.60°. By testing small flexural specimens cut from the plates, it was found out that the mechanical performance (peak flexural strength) correlates with the product of fibre volume content and cosine fibre orientation angle.
超高性能纤维增强混凝土（UHPFRC）是一种创新的水泥基工程材料。UHPFRC的力学性能不仅取决于混凝土基体和纤维的性能，还取决于这两个组分之间的相互作用。纤维分布受多种因素影响，以往的研究人员开发了不同的方法来测试纤维分布。本研究采用无损C形铁磁探头感应测试，研究了UHPFRC板中直钢纤维的分布情况。引入了一个带有衰减因子的简化表征方程，以考虑不同的板厚。该探头的有效测试深度经测试为24mm。通过应用该方法，可以对整个板材的纤维体积含量和纤维取向角进行校准。纤维体积含量总体上满足设计要求。纤维取向角呈正态分布，平均值为45.60°。通过测试从板材上切割下来的小尺寸弯曲试件，发现力学性能（峰值抗弯强度）与纤维体积含量和余弦纤维取向角的乘积相关。
