A novel casting procedure for SFRC piles without shear reinforcement using the centrifugal forming technique to manipulate the fiber orientation and distribution
A novel casting procedure for SFRC piles without shear reinforcement using the centrifugal forming technique to manipulate the fiber orientation and distribution
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DOI：
10.1016/j.conbuildmat.2021.124232
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发表时间：
2021-10
影响因子：
7.4
通讯作者：
R. A. Raju;M. Akiyama;Sopokhem Lim;Tatsuya Kakegawa;Yuka Hosono
中科院分区：
文献类型：
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作者：
R. A. Raju;M. Akiyama;Sopokhem Lim;Tatsuya Kakegawa;Yuka Hosono
钢纤维混凝土（SFRC）构件的结构性能主要取决于纤维的分布和取向。以往的实验研究表明，在制备过程中，纤维的分布和取向是随机的，难以控制。离心成形技术可以改善钢纤维在空心圆形钢纤维桩中的取向和分布，提高桩的抗剪强度。完成这一任务，就有可能在桩内用钢纤维代替抗剪钢筋，从而节省大量的时间和劳动力，从而提高桩施工行业所要求的高生产率。本文提出了一个新的试验程序，以(a)发展SFRC桩的浇筑程序，(b)研究无剪力加固的SFRC桩与有剪力加固的传统钢筋混凝土（RC）桩的抗剪强度。通过x射线技术研究了不同的配合比和浇筑方法，确定了最佳工艺，使纤维在SFRC桩中的分布和取向优于RC桩。离心成形方法影响纤维的取向，使其在剪应力方向（即周向）上取向。加载试验表明，钢纤维具有较好的抗剪增强作用，抗剪能力随钢纤维掺量的增加而增加。此外，与RC桩相比，SFRC桩具有稳定的裂缝扩展和改善的开裂后刚度，没有严重的混凝土损伤。
The structural performance of steel fiber-reinforced concrete (SFRC) members primarily depends on the distribution and orientation of the fibers. Previous experimental studies revealed that the distribution and orientation of fibers are random and hardly controlled during the fabrication process. The centrifugal forming technique may improve the orientation and distribution of steel fibers in hollow circular SFRC piles and increase the shear strength of the piles. Accomplishing this task can lead to the possible replacement of shear reinforcements with steel fibers in piles, thereby improving the demanding productivity that is desired in the pile construction industry by saving considerable time and labor. This paper presents a novel experimental program to (a) develop the casting procedure for SFRC piles and (b) investigate the shear strength of SFRC piles without shear reinforcement compared to that of conventional reinforced concrete (RC) piles with shear reinforcement. With the aid of X-ray technology, different mix proportions and casting methods were investigated to determine the optimum procedure, which produced fiber distributions and orientations in SFRC piles superior to those of RC piles. The centrifugal forming method influenced the orientation of the fibers so that they were oriented in the shear stress direction (i.e., circumferential direction). The loading test demonstrated that the steel fibers effectively worked as shear reinforcement and that the shear capacity increased with the steel fiber content. Moreover, the SFRC piles exhibited stable crack propagation and improved post-cracking stiffness without severe concrete damage compared to that of the RC piles.