The pull-out behavior of straight and hooked-end steel fiber from hybrid fiber reinforced cementitious composite: Experimental study and analytical modelling

2018 ◽  
Vol 206 ◽  
pp. 693-712 ◽  
Author(s):  
Fangqian Deng ◽  
Xiaoxiao Ding ◽  
Yin Chi ◽  
Lihua Xu ◽  
Li Wang
2016 ◽  
Vol 50 (30) ◽  
pp. 4291-4305 ◽  
Author(s):  
Jun Zhang ◽  
Zhenbo Wang ◽  
Qing Wang ◽  
Yuan Gao

The flexural performance of polyvinyl alcohol-steel hybrid fiber reinforced engineered cementitious composite with characteristics of low drying shrinkage special focus on impacts of steel fiber content and matrix strength has been investigated in both experimental and theoretical aspects in this paper. Four matrix types with water to binder ratio of 0.25, 0.35, 0.45, and 0.55 and three additional steel fiber contents in the composite with polyvinyl alcohol fiber content of 1.7% in volume were used in the test program. The experimental results show that cracking and flexural strength of the composites are increased with the addition of steel fiber. This enhancement becomes more and more pronounced with decreasing of water to binder ratio of the composites. Meanwhile, fracture mechanics-based flexural model is used to simulate the flexure performance of the polyvinyl alcohol -steel hybrid fiber reinforced engineered cementitious composite with characteristics of low drying shrinkage. The model results show that a double peak load is expected of the composites under bending load. The first peak is controlled by the fracture toughness of matrix or cracking strength of matrix, and the second peak is governed by the fiber bridging. The effect of addition of steel fiber in engineered cementitious composite with characteristics of low drying shrinkage on the first peak is unapparent. The impact of steel fiber on the second peak is significant. This enhancement of additional steel fiber gradually decreases with the decrease of water to binder ratio of the matrix, which coincides well with the experimental findings. The test results are compared to the model and reasonable agreement is found.


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.


2018 ◽  
Vol 162 ◽  
pp. 02001
Author(s):  
Wasan Khalil ◽  
Hisham Ahmed ◽  
Zainab Hussein

In this investigation, sustainable High Performance Lightweight Aggregate Concrete (HPLWAC) containing artificial aggregate as coarse lightweight aggregate (LWA) and reinforced with mono fiber, double and triple hybrid fibers in different types and aspect ratios were produced. High performance artificial lightweight aggregate concrete mix with compressive strength of 47 MPa, oven dry density of 1828 kg/m3 at 28 days was prepared. The Fibers used included, macro hooked steel fiber with aspect ratio of 60 (type S1), macro crimped plastic fiber (P) with aspect ratio of 63, micro steel fiber with aspect ratio of 65 (type S), and micro polypropylene fiber (PP) with aspect ratio of 667. Four HPLWAC mixes were prepared including, one plain concrete mix (without fiber), one mono fiber reinforced concrete mixes (reinforced with plastic fiber with 0.75% volume fraction), one double hybrid fiber reinforced concrete mixes (0.5% plastic fiber + 0.25% steel fiber type S), and a mix with triple hybrid fiber (0.25% steel fiber type S1+ 0.25% polypropylene fiber + 0.25% steel fiber type S). Fresh (workability and fresh density) and hardened concrete properties (oven dry density, compressive strength, ultrasonic pulse velocity, splitting tensile strength, flexural strength, static modules of elasticity, thermal conductively, and water absorption) were studied. Generally, mono and hybrid (double and triple) fiber reinforced HPLWAC specimens give a significant increase in splitting tensile strength and flexural strength compared with plain HPLWAC specimens. The percentage increases in splitting tensile strength for specimens with mono plastic fiber are, 20.8%, 31.9%, 36.4% and 41%, while the percentage increases in flexure strength are 19.5%, 37%, 33.9% and 34.2% at 7, 28, 60, 90 days age respectively relative to the plain concrete. The maximum splitting tensile and flexure strengths were recorded for triple hybrid fiber reinforced HPLWAC specimens. The percentage increases in splitting tensile strength for triple hybrid fiber reinforced specimens are 19.5%, 37%, 33.9% and 34.2%, while the percentage increases in flexure strength are 50.5%, 62.4. %, 66.8% and 62.2% at 7, 28, 60 and 90 days age respectively relative to the plain concrete specimens.


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