Flexural Behavior of Steel Fiber Reinforced Self-Stressing Concrete in Continuous Systems

2011 ◽  
Vol 675-677 ◽  
pp. 705-708
Author(s):  
Bo Xin Wang ◽  
Huan An He

Steel Fiber Reinforced Self-stressing Concrete (SFRSSC for short) is a new type of high performance cementitious composite with self-expansive performance and high tensile resistance. It can be used as a joint material in the new bridge construction or the old bridge rehabilitation. Because when SFRSSC is restrained by steel bars and other terminal conditions, it can create chemical pre-stressing force to enhance the cracking moments of the continuous beams. For purpose of utilizing the properties of SFRSSC, the primary goal of this research is to apply SFRSSC as a joint material to build continuous bridges. Firstly, the model experiments of 8 continuous Tbeams with SFRSSC layers are carried out. Secondly, based on the model experiments, flexural performance of the beams reinforced by SFRSSC layers is investigated. Owing to enhancement of steel fibers and self-stress induced by steel bars, the layers greatly improve the first-crack strength and stiffness of the continuous T-beams. The test results obviously indicate that the composite SFRSSC-RC continuous T-beams enhance the crack moment 51.4%~121% more than conventional concrete continuous beams. Furthermore, SFRSSC can help cancel out the relative deformation and stress due to new concrete shrinkage between new and existing concrete during the process transforming simply supported beams into continuous beams. It is concluded that flexural performance of continuous T-beams strengthened by SFRSSC is more greatly improved than that strengthened by conventional concrete.

2008 ◽  
Vol 400-402 ◽  
pp. 543-548
Author(s):  
Bo Xin Wang ◽  
Cheng Kui Huang

Steel Fiber Reinforced Self-stressing Concrete (SFRSSC) is a new type of fiber reinforced composite material. It has various applications in civil engineering for its well known superior properties such as self-expansive performance and high tensile resistance. However, it is not widely accepted as an effective reinforcement in the rehabilitation of the old bridges at present. The primary goal of this research is to apply SFRSSC to improve the crack resistance in the negative bending moment areas of the old bridges. Firstly, a computer analysis on the internal force of the continuous T-beams with 5 spans is given in this paper. The results show that the expansive action of SFRSSC can effectively decrease the internal force in the negative bending moment area. Meanwhile, based on the experiments of 5 composite concrete inverted T-beams, the crack resistance of the beams reinforced with SFRSSC layers is investigated. The test results obviously indicated that the composite layers enhanced the cracking moments 44.9% more than conventional concrete layers, though its height is only 13.9% of the cross section height. It is concluded that the continuous beams strengthened by SFRSSC has greatly improved the crack resistance in negative bending moment areas compared with the continuous beams strengthened by conventional concrete. According to the existing theoretical models, a procedure how to determine the self-stress is supplied and a formula which evaluating the crack resistance of composite T-beams in negative moment area is deduced in order to supply references to the old bridge rehabilitation design.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3522
Author(s):  
Marta Caballero-Jorna ◽  
Marta Roig-Flores ◽  
Pedro Serna

The use of synthetic fibers in fiber-reinforced concretes (FRCs) is often avoided due to the mistrust of lower performance at changing temperatures. This work examines the effect of moderate temperatures on the flexural strengths of FRCs. Two types of polypropylene fibers were tested, and one steel fiber was employed as a reference. Three-point bending tests were carried out following an adapted methodology based on the standard EN 14651. This adapted procedure included an insulation system that allowed the assessment of FRC flexural behavior after being exposed for two months at temperatures of 5, 20, 35 and 50 °C. In addition, the interaction of temperature with a pre-cracked state was also analyzed. To do this, several specimens were pre-cracked to 0.5 mm after 28 days and conditioned in their respective temperature until testing. The findings suggest that this range of moderate temperatures did not degrade the behavior of FRCs to a great extent since the analysis of variances showed that temperature is not always a significant factor; however, it did have an influence on the pre-cracked specimens at 35 and 50 °C.


2020 ◽  
Vol 26 (2) ◽  
pp. 111-128
Author(s):  
Tamara M. Hasan ◽  
Ahmed S. Ali

The massive growth of the automotive industry and the development of vehicles use lead to produce a huge amount of waste tire rubber. Rubber tires are non-biodegradable, resulting in environmental problems such as fire risks. In this search, the flexural behavior of steel fiber reinforced self-compacting concrete (SFRSCC) beams containing different percentages and sizes of waste tire rubbers were studied and compared them with the flexural behavior of SCC and SFRSCC. Micro steel fiber (straight type) with aspect ratio 65 was used in mixes. The replacement of coarse and fine aggregate was 20% and 10% with chip and crumb rubber. Also, the replacement of limestone dust and silica fume was 50%, 25%, and 12% with ground rubber and very fine rubber, respectively. Twelve beams with small-scale (L=1100mm, h = 150mm, b =100mm) were tested under two points loading (monotonic loading). Fresh properties, hardened properties, load-deflection relation, first crack load, ultimate load, and crack width were investigated. Two tested reinforced concrete beams from experimental work were selected as a case study to compare with the results from ABAQUS program (monotonic loading). These two reinforced concrete beams were simulated as a parametric study under repeated loading using this finite element program. The results showed that the flexural behavior of SFRSCC beams containing rubber was acceptable when compared with flexural behavior of SCC and SFRSCC beams (depended on load carrying capacity). Cracks width was decreased with the addition of steel fibers and waste tires rubber.  An acceptable agreement can be shown between the results of numerical analysis and the results obtained from experimental test (monotonic loading). Insignificant ultimate load differences between the results of monotonic loading and repeated loading                                                                                                                                                                                           


Sign in / Sign up

Export Citation Format

Share Document