An investigation on the effect of hybrid fiber reinforced on the flexural behavior of <scp>RC</scp> beams having different lap‐spliced lengths

Structural ductility in the case of plastic hinges forming close to a lap splice has been an open issue with the revision process of the next version of Eurocode EC2 concerning reinforced‐concrete structures. This research has provided experimental evidence by the large experimental campaign for the background for revision of the Eurocode EC2. Within this context, 38 specimens were tested in four‐point bending, with the longitudinal bars either lap‐spliced (partly or fully), or un‐spliced (for reference). The tests were carried out involving the variation of the bar diameter (12, 16, 20, and 25 mm), and the lap length (20–60 times the bar diameter). The main result is the sizeable enhancement of the structural ductility brought in by the extension of the lap length in excess of the length required by the yielding of the longitudinal bars. Based on these findings, a preliminary model is developed to describe the bond‐stress profiles in lap splices, after the yielding of the bars.

Section: Introductionmentioning

confidence: 99%

Behavior of lap splices in reinforced concrete beams after bar yielding

Haavisto

Alho

Laaksonen

2023

“…In recent years, researchers have done a lot of research on the effect of different types of fibers on the different properties of concrete, including its mechanical properties, and all the evidence indicates that the use of fibers alone or in a hybrid form can improve the mechanical behavior of fibers. Also, the use of environmentally friendly additives along with fibers, besides being sustainable, can help make high‐performance concrete 40–49 …”

Section: Introductionmentioning

confidence: 99%

“…Also, the use of environmentally friendly additives along with fibers, besides being sustainable, can help make high-performance concrete. [40][41][42][43][44][45][46][47][48][49] Previous research has shown that the use of recycled polypropylene fiber improves the mechanical behavior and durability of concrete. 50,51 In this paper, the macro-synthetic fibers, Forta and Barchip, were made of polyolefin.…”

Section: Introductionmentioning

confidence: 99%

Impact resistance and mechanical properties of fiber‐reinforced concrete using string and fibrillated polypropylene fibers in a hybrid form

Najaf

Abbasi

2022

In this study, the macro‐synthetic polypropylene fibers Forta and Barchip are used. The fibers are added at 0.5%, 1%, 1.5%, and 2% by weight of cement. Additionally, various fiber combinations with varying percentages are employed to create the concrete. Cubic specimens, bending beams, and impact specimens are all prepared on a percentage basis of fiber. The findings indicated that utilizing 1.5% fibrillated Forta fibers raised the compressive strength of the concrete by 18% and the flexural strength of the concrete by 58%. By increasing the usage of Barchip single‐strand fibers by 1.5%, the compressive strength increased by 36%, and the flexural strength increased by 89%. The highest ductility rate refers to the specimen containing 1.5% Forta fiber, with an energy capacity of 672 J. All the hybrid samples also possess a high ductility ratio. Forta fibrillated fibers are more effective in ductility, while Barchip monofilament fiber types can impressively increase the flexural strength of concrete. The hybrid usage of fibers improved compressive strength by 32% and flexural strength by 85%. Additionally, by combining fibers in hybrid form, energy absorption, ductility, impact resistance, and residual flexural strength are increased by 22, 2.3, 3.6, and 5.6 times, respectively, over the control sample.

“…Improving the brittleness and flexural strength and toughness of concrete by adding fibers is one of the most common methods for toughening concrete at this stage, [15][16][17][18][19] which is known as fiber-reinforced concrete (FRC). The addition of fiber can force the extension path of the crack tip in the concrete to change or make expected large cracks become an increasingly subtle crack field, increasing the energy consumed for crack development and playing a role in crack resistance and toughening.…”

Section: Introductionmentioning

confidence: 99%

Study on the flexural properties and fiber‐selection method of fiber‐reinforced geopolymer concrete

Zhao

Wang

et al. 2022

In order to study the effect of different types of fibers on the bending properties of geopolymer concrete (GPC), a series of fiber‐reinforced geopolymer concrete (FRGPC) samples were prepared, and their flexural properties were evaluated by four point bending test and bending toughness evaluation index. Then, based on the fiber characteristic value (λ), a new bending strength prediction model and a three‐dimensional (3D) curved surface prediction model of the bending toughness of FRGPC are proposed and fitted. Finally, a new method for the selection of fibers in GPC is designed by calculating the derivative of the quadratic relationship between fiber reinforcement factor (S) and λ. The results show that all types of fibers have a certain effect on improving the bending strength of GPC samples, and the lifting rate is end‐hook steel fiber (SF), basalt fiber (BF), and short polyethylene polypropylene fiber (SPPF), from high to low. Mixing the above types of fibers with long polypropylene fibers (LPPF) will produce better performance. Among them, the hybrid fiber‐containing SF has the best performance. The bending performance prediction model deduced in this paper has a good correlation coefficient, which can be used to predict the bending performance of FRGPC. By making dS/dλ = 0 can calculate the optimal λ, and this λ can maximize the parameter S and guide the selection of optical fibers.