scholarly journals Damage Evolution of Steel-Polypropylene Hybrid Fiber Reinforced Concrete: Experimental and Numerical Investigation

2018 ◽  
Vol 2018 ◽  
pp. 1-23
Author(s):  
Lihua Xu ◽  
Cuimei Wei ◽  
Biao Li

This paper presents an experimental investigation on the stress-strain behavior and damage evolution of steel-polypropylene hybrid fiber reinforced concrete (HFRC) with different fiber types, volume fractions, and aspect ratios. The damage evolution laws of HFRC were obtained using uniaxial cyclic compression and tension tests. The results show that the addition of hybrid fiber has a significant synergetic effect on the mechanical behavior of concrete. The peak strength, peak strain, toughness, and postpeak ductility of HFRC under both tension and compression are improved, and the damage accumulation and stiffness degradation are alleviated by increasing volume fractions of SF and PF, as well as aspect ratios of SF. Moreover, the steel fiber volume fraction shows a more pronounced effect than that of other considered factors on the enhancement of cyclic mechanical parameters of HFRC. Based on the unloading stiffness degradation process, analytical equations were, respectively, proposed to generalize the damage progression of HFRC under compression and tension, with the effects of hybrid fiber taken into consideration. Finally, the proposed uniaxial damage evolution equations combined with the calibrated concrete damaged plasticity (CDP) model in ABAQUS were used to predict the responses of HFRC materials and structural members subjected to shear and seismic loads. The comparisons between the numerical predictions and experimental results show a good agreement.

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Lihua Xu ◽  
Biao Li ◽  
Yin Chi ◽  
Changning Li ◽  
Biao Huang ◽  
...  

This paper investigates the cyclic stress-strain behavior of steel-polypropylene-blended fiber-reinforced concrete (BFRC) under uniaxial cyclic compression. A total of 48 prism specimens were tested for different fiber volume fractions and aspect ratios. The results show that the introduction of blended fibers has synergetic effects on improving the cyclic behavior of concrete in terms of peak strength, postpeak ductility, hysteretic energy dissipation, and stiffness degradation. Moreover, the increase in the volume fractions of both steel and polypropylene fibers can lead to a remarkable decrease in plastic strain accumulation. Furthermore, the stiffness degradation ratio as well as the stress deterioration ratio of BFRC can be significantly alleviated in comparison with those of plain concrete, notwithstanding that the degradation amount is insensitive to the variations of fiber parameters. Subsequently, based on the test results, a constitutive model is developed to generalize the cyclic stress-strain responses of BFRC, with the contributions of blended fibers taken into account. The developed model is then verified by independent experimental results and other test data reported in the literature. It is observed that the prediction yields a close estimation of the cyclic compressive behavior of BFRC with varying fiber parameters.


2019 ◽  
Vol 8 (3) ◽  
pp. 1025-1028

The present work is enhancement of near surface characteristics for hybrid fiber reinforced concrete (aspect ratio 40+100). Here in this research work an attempt has made to study water absorption values for different types of fiber reinforced concrete, which are having different aspect ratios like 40, 100 and 40+100. Concrete mix along with fibers are casted and cured for 28days. Both water absorption test and sorptivity tests carried on hardened concrete. The main objective is to check variation in absorption values due to addition of different types of fibers. Here totally five different types of fibers are considered like steel fiber, Galvanized iron fibres, High density polyethylene fibres, waste plastic fiber and polypropylene fibers Experimental investigation shows that except polyprolene hybrid mix concrete other hybrid mixes has showed good results. But as compared to mono fiber reinforced concrete hybrid fiber reinforced concrete has showed better results. This research was aimed to provide benchmark for future research works on near surface characteristics of hybrid fiber reinforced concrete.


2020 ◽  
Vol 10 (5) ◽  
pp. 733-739
Author(s):  
Saman Hedjazi ◽  
Daniel Castillo

Using fibers in concrete, has been recognized as a practical method to improve concrete properties such as reduction in crack development and higher resistance against impact and abrasion. Dry cementitious material exhibits very high electrical resistivity. However, fibers can significantly decrease the electrical resistivity of concrete which affects its insulating nature and has negative effects on concrete properties such as durability and also in special cases such as rail road ties production. In this paper the effect of steel, glass, and nylon fiber on the electrical properties of Fiber Reinforced Concrete (FRC) is investigated. Six different fiber volume fractions (Vf) (0.10% vol., 0.25% vol., 0.50% vol., 0.75% vol., 1.00% vol., 1.50% vol.) and several water-to-cement ratios (w/c) were considered as the main variables in the present study. In order to test the electrical properties of FRC, 100 mm × 200 mm cylinders were casted, cured and tested. The four point technique was used for measuring the surface electrical resistivity of concrete after curing in water for 3, 7, 28, and 44 days. Additionally, the compressive strength of each specimen was determined experimentally using the Compression Test Machine. The results revealed that the electrical resistivity of FRC decreases with an increase in fiber content but different types of fibers have different electrical effects on concrete. The effects of different volume fractions of three fiber types, together with different concrete mix proportions are presented and discussed.


2021 ◽  
Vol 264 ◽  
pp. 02030
Author(s):  
Leonid Dvorkin ◽  
Oleh Bordiuzhenko ◽  
Vadim Zhitkovsky ◽  
Svyatoslav Gomon ◽  
Sviatoslav Homon

Adding different fiber types may yield improvement of steel fiber reinforced concrete (SFRC) features. Therefore, the investigation of hybrid fiber reinforced concrete (HFRC) mechanical properties is relevant. The effect of adding hybrid steel and basalt fiber on the mechanical properties of fine-grained concrete is studied. It is shown that hybrid fiber reinforcement using optimal steel and basalt fiber ratio allows preventing concrete mixtures' segregation and improving their structure homogeneity. This, in turn, allows achieving higher concrete strength values. In most cases, the design of such concrete compositions is based on engineering experience that limits the designers' capabilities. Therefore, an effective methodology for proper HFRC composition design should be developed. The present study is focused on developing such a methodology. The developed methodology includes using the mathematical experiments planning method to design optimal composition of high-strength fine-grained fiber reinforced concrete with hybrid steel and basalt fiber reinforcement. It is demonstrated that the proposed method can be effectively used for the design of optimal compositions of HFRC.


2022 ◽  
pp. 204141962110654
Author(s):  
Yong Zhang ◽  
Li Chen ◽  
Dong-lei Zhou

In this study, the dynamic mechanical properties of hybrid fiber reinforced concrete (HFRC) are analyzed with respect to failure mode, dynamic increase factor (DIF), and peak strain by means of a SHPB testing apparatus. The factors that influence the dynamic mechanical properties include fiber type and fiber content. It is concluded that the best dynamic mechanical properties of fibers are CS-PHFRC at medium and low strain rates and AS-PHFRC at a high strain rate. Within a certain range, the higher the fiber content is, the larger the DIF of the corresponding HFRC and the more obvious the increase in dynamic compressive strength. AS-CSHFRC improves the dynamic compressive deformability of the HFRC. The polypropylene fiber causes plasticity, as shown in the failure mode of concrete. The Ottosen nonlinear elastic model, modified by introducing the damage factor, can better describe the dynamic mechanical properties of HFRC.


2021 ◽  
Vol 1895 (1) ◽  
pp. 012053
Author(s):  
Hadeel M. Shakir ◽  
Ahmed Farhan Al-Tameemi ◽  
Adel A. Al-Azzawi

2013 ◽  
Vol 327 ◽  
pp. 201-204
Author(s):  
Jin Song Shi ◽  
Bo Yuan ◽  
Da Zhang Wang ◽  
Zhe An Lu

In order to investigate the difference of current toughness index standards for fiber reinforced concrete, two main groups of specimens were made to take bending toughness test with the requirements of corresponded standards, loading methods and loading speeds, which are ASTM C1018 in America, ACI 544 and JSCE G552 in Japan. United with software Origin, the load-deflection curves gathered from bending test was calculated with relative standards. The results show that the calculated toughness index value with ASTM C1018-98 in America is more accurate with three grades but the requested deflection of testing is much longer than others while ACI 544 and JSCE G552 in Japan are quite the contrary.


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