Experimental investigation of thermal expansion and concrete strength effects on FRP bars behavior embedded in concrete

2018 ◽  
Vol 163 ◽  
pp. 1-8 ◽  
Author(s):  
Ferhat Aydin
Keyword(s):  
Experimental Investigation ◽  
Thermal Expansion ◽  
Concrete Strength ◽  
Frp Bars

Utilizing alkali-activated materials as ordinary Portland cement replacement to study the bond performance of fiber-reinforced polymer bars in seawater sea-sand concrete

2022 ◽  
pp. 136943322110651
Author(s):  
Ruiming Cao ◽  
Bai Zhang ◽  
Luming Wang ◽  
Jianming Ding ◽  
Xianhua Chen
Keyword(s):  
Tensile Strength ◽  
Bond Strength ◽  
Ordinary Portland Cement ◽  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Bond Performance ◽  
Reinforced Polymer ◽  
Sea Sand ◽  
Frp Bars ◽  
Alkali Activated

Alkali-activated materials (AAMs) are considered an eco-friendly alternative to ordinary Portland cement (OPC) for mitigating greenhouse-gas emissions and enabling efficient waste recycling. In this paper, an innovative seawater sea-sand concrete (SWSSC), that is, seawater sea-sand alkali-activated concrete (SWSSAAC), was developed using AAMs instead of OPC to explore the application of marine resources and to improve the durability of conventional SWSSC structures. Then, three types of fiber-reinforced polymer (FRP) bars, that is, basalt-FRP, glass-FRP, and carbon-FRP bars, were selected to investigate their bond behavior with SWSSAAC at different alkaline dosages (3%, 4%, and 6% Na2O contents). The experimental results manifested that the utilization of the alkali-activated binders can increase the splitting tensile strength ( ft) of the concrete due to the denser microstructures of AAMs than OPC pastes. This improved characteristic was helpful in enhancing the bond performance of FRP bars, especially the slope of bond-slip curves in the ascending section (i.e., bond stiffness). Approximately three times enhancement in terms of the initial bond rigidity was achieved with SWSSAAC compared to SWSSC at the same concrete strength. Furthermore, compared with the BFRP and GFRP bars, the specimens reinforced with the CFRP bars experienced higher bond strength and bond rigidity due to their relatively high tensile strength and elastic modulus. Additionally, significant improvements in initial bond stiffness and bond strength were also observed as the alkaline contents (i.e., concrete strength) of the SWSSAAC were aggrandized, demonstrating the integration of the FRP bars and SWSSAAC is achievable, which contributes to an innovative channel for the development of SWSSC pavements or structures.

Transverse Thermal Expansion of FRP Bars Embedded in Concrete

2005 ◽  
Vol 9 (5) ◽  
pp. 377-387 ◽  
Author(s):  
Radhouane Masmoudi ◽  
Ali Zaidi ◽  
Patrick Gérard
Keyword(s):  
Thermal Expansion ◽  
Frp Bars

Effect of confinement on the behaviour of high-strength lightweight concrete columns

1986 ◽  
Vol 13 (6) ◽  
pp. 741-751 ◽  
Author(s):  
R. Basset ◽  
S. M. Uzumeri
Keyword(s):  
Experimental Investigation ◽  
Lightweight Concrete ◽  
Concrete Strength ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Concrete Columns ◽  
Lightweight Aggregate Concrete ◽  
Test Results ◽  
Aggregate Concrete ◽  
Concrete Confinement

This paper summarizes an experimental investigation into the behaviour of high strength sand – lightweight concrete columns confined with rectangular ties. Fifteen reinforced and three unreinforced specimens were tested under monotonically increasing axial compression. Variables considered in this study were the longitudinal steel distribution and tie configuration, the tie steel spacing, the amount of tie steel, and the amount of longitudinal steel.The results indicated that unconfined high-strength lightweight aggregate concrete is a brittle material. The addition of lateral confining steel significantly improved the behaviour of this material, with a large amount of lateral steel resulting in very ductile behaviour. The tie configuration and resulting distribution of longitudinal steel contributed significantly to the confinement of concrete, with well-distributed steel resulting in improved behaviour. The ratio of specimen to cylinder concrete strength was observed to be 0.98, which is much higher than the commonly assumed value of 0.85.The test results were compared with results from selected theoretical confinement models. Based on the results of this investigation, existing models for concrete confinement give unconservative results for high-strength lightweight aggregate concrete and overestimate the ductility that can be achieved with this material. Key words: columns, confinement, ductility, high-strength concretes, lightweight aggregate concretes, reinforcement, stress–strain relationships, tests, ties, toughness.

Bend Strength of FRP Bars: Experimental Investigation and Bond Modeling

2017 ◽  
Vol 29 (7) ◽  
pp. 04017024 ◽  
Author(s):  
Thanongsak Imjai ◽  
Maurizio Guadagnini ◽  
Kypros Pilakoutas
Keyword(s):  
Experimental Investigation ◽  
Bend Strength ◽  
Frp Bars

Behavior of Continuous FRP Rectangular Spirals as Shear Reinforcement for Concrete Beams

2011 ◽  
Vol 418-420 ◽  
pp. 307-312
Author(s):  
Shi Yong Jiang ◽  
Bing Hong Li ◽  
Qian Hua Shi ◽  
Xian Qi Hu
Keyword(s):  
Experimental Investigation ◽  
Tensile Strength ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Test Method ◽  
Test Results ◽  
Shear Reinforcement ◽  
Straight Portion ◽  
Embedment Length

The replacement of steel stirrups with FRP stirrups in concrete structures can significantly improve the durability under severe environmental conditions, increase the service life of the structure. In some cases where the application of traditional concrete structures is restricted, such as structures that require the environment without magnetic and electric interferences, the best way is to use nonmetallic materials. Considering the unique properties compared with traditional reinforcements, FRP reinforcements is very suitable in such cases. This paper discussed the behavior of FRP stirrups used as shear reinforcement for concrete structures, continuous FRP rectangular spirals, a type of FRP stirrups, was used in the experimental investigation. Inspired by the test method suggested by ACI Committee 440, L shape specimen and U shape specimen are designed to test the tensile strength of continuous FRP rectangular spirals. Through the analysis of test results, it is indicated that the strength of the bent portion of FRP spirals is significantly lower than that of the straight portion, and the strength of FRP spirals would increase as the concrete strength or the embedment length of the bent portion increased. The loading mechanism of continuous FRP rectangular spirals embedded in concrete beams can be better represented by U shape specimen compared with L shape specimens, it is suggested by the author that the U shape specimen can be use when the dimension of FRP stirrups or spirals does not meet the requirements of ACI Committee 440 test method.

Magnetic and crystallographic phase transitions in Dy p Gd 1- p VO 4

1984 ◽  
Vol 391 (1800) ◽  
pp. 85-107 ◽  
Keyword(s):  
Experimental Investigation ◽  
Thermal Expansion ◽  
Phase Transitions ◽  
Quadrupole Moment ◽  
Magnetic Phase ◽  
Phase Changes ◽  
Magnetic Phase Transitions ◽  
Compositional Dependence ◽  
Quadrupole Interactions ◽  
Pair Model

The compositional vanadate system Dy p Gd 1- p VO 4 (0 ≤ p ≤ 1) displays successive crystallographic and magnetic phase transitions below 14 K. An experimental investigation of these phase changes has been made with thermal expansion methods and Mössbauer spectroscopy. It is found that there is a surprising variation of the compositional dependence of the transition temperatures T D ( p ) and T N ( p ), which cannot be adequately explained by conventional pseudo-spin molecular field and pair model approximations. A detailed formalism has been developed that accounts for the observations in terms of a magneto-strictively induced quadrupole moment on the Gd 3+ ions in the mixed crsytal system and, concomitant quadrupole interactions between the Dy 3+ and Gd 3+ ions. The application of the formalism to the corresponding variation of T D ( p ) in the simple diluent system Dy p Y 1- p VO 4 (0 ≤ p ≤ 1) is also discussed.

scholarly journals The Attitude of Load-Deflection for Concrete Beams with Polymer Reinforcement

2019 ◽  
Vol 26 (4) ◽  
pp. 32-37
Author(s):  
Ahmed Saadon ◽  
Abdulnasser Abbas ◽  
Ali Khalaf
Keyword(s):  
Compressive Strength ◽  
Experimental Test ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Control Beam ◽  
Steel Bars ◽  
Conservative Values ◽  
Frp Bars

In this research, the load-deflection behavior is explored for concrete beams reinforced with FRP bars (polymer reinforcement). An experimental test is done for a total of five beams subjected to 4-point loading. The tested specimens are of dimensions; 2100 mm (length), 200 mm (width) and 300 mm (depth), while the used compressive strength for concrete is f’c = 60 MPa. Four beams were longitudinally reinforced by various CFRP rebar numbers, and the last beam was reinforced only by steel bars as control beam. Relationships for load-deflection were drawn and the influence of several factors was debated on this relationship. It was exhibited that the failure of FRP reinforced samples was generally ruled by the concrete strength. When the ratio of reinforcement rising by 50%, 100% and 150%, the ultimate load increased by 15%, 29% and 38%, respectively, while the recorded deflection at ultimate load decreased by 7%, 16% and 24%, respectively. For the ultimate load of the studied beams, outcomes exhibited that the equations of the American code ACI 440.1R give very close values with the test values, while they give very conservative values to the deflection at ultimate load which are smaller than the test values by about (37%-45%)

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