A study of some factors affecting the fiber–matrix bond in steel fiber reinforced concrete

1990 ◽  
Vol 17 (4) ◽  
pp. 610-620 ◽  
Author(s):  
Nemkumar Banthia
Keyword(s):  
Reinforced Concrete ◽  
Load Transfer ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Factors Affecting ◽  
Surrounding Matrix ◽  
Pull Out ◽  
Fiber Matrix

With the objective of understanding the reinforcing mechanisms of fibers in steel fiber reinforced concrete, the bond between the fibers and the surrounding matrix is studied by conducting single fiber pull-out tests on fibers bonded in cementitious matrices. Various matrix compositions and fiber geometries have been investigated and the effects of various other factors on the pull-out behavior of the fibers have been quantified through pull-out load–extension plots. Finally, the various modes of fiber–matrix load transfer have been discussed and the favorable and unfavorable conditions for such a transfer have been recognized. Key words: steel fiber reinforced concrete, toughness, fiber–matrix bond, deformed fiber, pull-out tests, load–extension plots.

scholarly journals Microscale Cohesive-Friction-Based Finite Element Model for the Crack Opening Mechanism of Hooked-End Steel Fiber-Reinforced Concrete

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 669
Author(s):  
Yassir M. Abbas
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Crack Opening ◽  
Fiber Reinforced Concrete ◽  
Embedment Depth ◽  
Fe Model ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Matrix

The entire mechanical properties of steel fiber-reinforced concrete (SFRC) are significantly dependent on the fiber–matrix interactions. In the current study, a finite element (FE) model was developed to simulate the pullout response of hooked-end SFRC employing cohesive–frictional interactions. Plain stress elements were adapted in the model to exemplify the fiber process constituents, taking into consideration the material nonlinearity of the hooked-end fiber. Additionally, a surface-to-surface contact model was used to simulate the fiber’s behavior in the pullout mechanism. The model was calibrated against experimental observations, and a modification factor model was proposed to account for the 3D phenomenalistic behavior of the pullout behavior. Realistic predictions were obtained by using this factor to predict the entire pullout-slip curves and independent results for the peak pullout load. The numerical results indicated that the increased fiber diameter would alter the mode of crack opening from fiber–matrix damage to that combined with matrix spalling, which can neutralize the sensitivity of the entire pullout response of hooked-end steel fiber to embedment depth. Additionally, the fiber–matrix bond was enhanced by increasing the fiber’s surface area, sensibly leading to a higher pullout peak load and toughness. The developed FE model was also proficient in predicting microstructural stress distribution and deformations during the crack opening of SFRC. This model could be extended to fully model a loaded SFRC composite material by the inclusion of various randomly oriented dosages of fibers in the concrete block.

Anchorage Capacity of Headed Bars in Steel Fiber Reinforced Concrete

2021 ◽  
Author(s):  
Payal Sachdeva ◽  
A.B. Danie Roy ◽  
Naveen Kwatra
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Failure Modes ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Concrete Compressive Strength ◽  
Pull Out

Headed bars (HB) with different head shapes (Square, Circular, and Rectangular) and bar diameters (db: 16, 20, and 25 mm) embedded in steel fiber reinforced concrete have been subjected to pull-out test. The influence of head shapes, concrete compressive strength (M20 and M40), db, and steel fibers (0, 0.5, 1, and 1.5%) on the anchorage capacity of HB have been evaluated. Numerical model for improving the anchorage capacity of HB has also been proposed. Results have revealed that the anchorage capacity of HB increases with the increase in concrete compressive strength, db, and steel fibers, which have been validated by non-linear regression analysis using dummy variables. Two failure modes namely, steel and concrete-blowout have been observed and the prevailing mode of failure is steel failure. Based on load-deflection curves and derived descriptive equations, it is observed that the circular HB has displayed the highest peak load.

Experimental Study on Shear Capacity of Prestressed SFRC Beams

2012 ◽  
Vol 256-259 ◽  
pp. 926-929
Author(s):  
Li Bing Jin ◽  
De Cai Chen ◽  
Ji Peng Qi
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Enhancement Effect ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Factors Affecting

In order to study the shear capacity enhancement effect of prestressed technology to steel fiber reinforced concrete, the practical formulas were proposed for evaluating the shear-strength of unbonded prestressed steel-fiber reinforced concrete beams (UPSFRCB) through the test and study of shear capacity of UPSFRCB with simply supported ends. Various factors affecting the shear strength of UPSFRCB, such as steel fiber, prestress and shear-span to depth ratio were analyzed. The result is of importance to the popularization and application of prestressed steel-fiber reinforced concrete.

scholarly journals Experimental Investigation on Mechanical Behavior of Anchor and Shotcrete Support System Under Axial Pull-out Action

2021 ◽  
Author(s):  
Xiliang Liu ◽  
Feiyue Sun ◽  
Fuli Kong ◽  
Jiaqi GUO
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Behavior ◽  
Support System ◽  
Steel Fiber ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Pull Out ◽  
Failure Properties

Abstract Based on axial pull-out performance tests of anchor and shotcrete support system with three types of plates and two kinds of shotcretes (plain and steel fiber reinforced concrete) conducted by use of the multi-functional testing system. The mechanical behavior of the anchor and shotcrete support system with the different plate and shotcrete such as the pull-out performance of support system, deformation and failure properties of shotcrete was studied and analyzed. Experimental results showed that the relationship curves between elongation and drawing force has three stages, which are elastic, yielding and strengthening. Different plate types have obvious influence on the tensile stiffness during the elastic stage. The steel fiber reinforced concrete spray layer can improve the yield strength of rockbolt under the coupling effect by the support system. The strain at the interface between the initial shotcrete layer and surrounding rock mass is greater than that of the external surface of the resprayed shotcrete layer, though they are equal far away from the rockbolt hole. The shotcrete strain values of steel fiber reinforced concrete is lower than that of plain concrete, and the shotcrete strain values decreases with the improvement of steel fiber content. For shotcrete strain values on the same position, the higher they are the steel fiber content, the lower their strain will be. The failure of plain shotcrete usually begins around of rockbolt hole, when the interfacial stress between the initial shotcrete layer and surround rock is higher than that in the initial shotcrete layer and resprayed shotcrete layer. The steel fiber can effectively improves the toughness, anti-cracking performance and prevent fracture of shotcrete from failure properties.

Sign in / Sign up

Export Citation Format

Share Document