Residual Mechanical Properties of Hybrid Fiber Reinforced HPC Exposed to High Temperatures

2016 ◽  
Vol 722 ◽  
pp. 52-58 ◽  
Author(s):  
Jan Fořt ◽  
Anton Trník ◽  
David Čítek ◽  
Zbyšek Pavlík
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Performance ◽  
Structural Changes ◽  
Simultaneous Thermal Analysis ◽  
Fiber Reinforced Concrete ◽  
Water Vapor Transport ◽  
Fiber Reinforced ◽  
Temperature Exposure ◽  
Hybrid Reinforcement

The effect of high temperature load on mechanical properties and porosity of a newly designed Ultra High Performance Fiber Reinforced Concrete (UHPFRC) is studied. The hybrid reinforcement of UHPFRC is based on a mixture of polypropylene and steel fibers. In order to identify influence of high temperature exposure on UHPFRC, its residual mechanical parameters such as compressive strength, flexural strength and Young’s modulus of elasticity are accessed. Moreover, residual bulk density, matrix density and total open porosity are examined and related to the monitored structural changes. Simultaneous Thermal Analysis (STA) is employed in order to describe transformation processes during high temperature loading. The conducted tests provide practical information for controlled regulation of water vapor transport in a low permeable cementitious composite in order to decrease risk of spalling.

The Effect of High Temperature Exposure on Properties of Hybrid Fiber Reinforced UHPC

2017 ◽  
Vol 909 ◽  
pp. 275-279
Author(s):  
Jan Fořt ◽  
David Čítek ◽  
Milena Pavlíková ◽  
Zbyšek Pavlík
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Structural Changes ◽  
Physical And Mechanical Properties ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
High Temperature Exposure ◽  
High Performance Fiber ◽  
Concrete Damage ◽  
Temperature Exposure

High Performance Fiber Reinforced Concrete (HPFRC) became very popular material for its high mechanical strength, elastic modulus and corrosion resistance. However, also its high-temperature resistance is of a particular importance because of the fire safety. Therefore, the effect of high-temperature exposure on UHPC reinforced by combination of steel and PVA fibers was studied in the paper. PVA fibers were used to moderate concrete damage induced by water vapor evaporation from dense UHPC matrix. The UHPFRC samples were exposed to the temperatures of 200 °C, 400 °C, 600 °C, 800 °C, and 1 000 °C respectively. Concrete structural changes induced by high temperature action were described by the measurement of basic physical and mechanical properties. The realized experiments provide information on the changes of concrete porosity and loss of mechanical resistivity.

EXPERIMENTAL STUDY OF ULTRA-HIGH PERFORMANCE FIBER REINFORCED CONCRETE DOSAGES WITH ULTRA FAST SETTING TIME

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Ester Gimenez-Carbo ◽  
Raquel Torres ◽  
Pedro Serna
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Performance ◽  
Mixing Time ◽  
Setting Time ◽  
Fiber Reinforced Concrete ◽  
Strength Development ◽  
Fiber Reinforced ◽  
High Performance Fiber ◽  
Compressive And Flexural Strengths

The overall objective of the work is the development of ultra high performance fiber reinforced concrete (UHPFRC) dosages that can be used for shotcrete. In this study, a number of UHPFRC mixtures with different amount of admixtures (plasticizers and accelerating) and different mixing time were tested, to increase either the rate of stiffening or setting of the concrete or the rate of hardening and early-strength development. Workability, consistency and mechanical properties of UHPFRC including compressive and flexural strengths at different ages were assessed. Results showed mixtures than begin their first setting in less than 1 minute, with very good mechanical properties in 24 hours, and without reducing the compressive strength at 28 days. From the results obtained, various uses of these mixtures are proposed taking into account, the new context of the Construction field, with the appearance of new placing concrete techniques.

Influence of Different Mechanical Properties to the Concrete Penetration Resistance

2014 ◽  
Vol 982 ◽  
pp. 119-124 ◽  
Author(s):  
Tomáš Vavřiník ◽  
Jan Zatloukal
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Speed ◽  
High Performance ◽  
High Performance Concrete ◽  
Penetration Resistance ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

This paper describes influence of different mechanical properties to the concrete penetration resistance. The resistance is evaluated on the basis of the presented experimental program. In the experiment, non-deformable ogive-nose projectiles with diameter of 7.92 mm and mass of 8 g with impact velocity of about 700 m/s were hitting center of the specimens. Determination of the concrete penetration resistance was than based on projectile residual velocity obtained from high-speed camera record. The specimens were made from high strength concrete, steel fiber-reinforced concrete, ultra-high performance concrete and ultra-high performance fiber-reinforced concrete with different fiber content. The concrete penetration resistance was evaluated on total 32 specimens. Influence of mechanical properties, addition of coarse aggregate and steel fibers were discussed. Mechanical properties of the tested materials were investigated on total 125 specimens. Data from the measurements were used for creation of new RHT concrete models in Autodyn. In order to confirm experiment's setup and results, numerical analysis was performed in Autodyn. Results of the numerical simulations were compared to the experimental program.

The Effect of Elevated Temperature on High Performance Fiber Reinforced Concrete

2015 ◽  
Vol 824 ◽  
pp. 191-195 ◽  
Author(s):  
Jan Fořt ◽  
Jaroslav Pokorný ◽  
David Čítek ◽  
Jiří Kolísko ◽  
Zbyšek Pavlík
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Elevated Temperature ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
Building Design ◽  
Fiber Reinforced Concrete ◽  
Material Structure ◽  
Fiber Reinforced ◽  
High Performance Fiber

High performance fiber reinforced concrete (HPFRC) became very popular material due to its high strength, elastic modulus, corrosion and fire resistance. However, detail description of HPFRC behaviour is necessary for its application and an effective building design and development. Here, also the fire safety of buildings must be considered. Therefore, the effect of elevated temperature on HPFRC is studied in the paper. For the reference material, experimental assessment of basic physical and mechanical properties is done. Then, the HPFRC samples are exposed to the temperatures of 600 and 800 °C respectively, and the effect of a high temperature exposure on material structure is examined. It is found that the applied high temperature loading significantly increases material porosity due to the physical, chemical and combined damage of material inner structure, and negatively affects also the pore size distribution.

High-temperature testing of high performance fiber reinforced concrete

2016 ◽  
Author(s):  
Jan Fořt ◽  
Eva Vejmelková ◽  
Milena Pavlíková ◽  
Anton Trník ◽  
David Čítek ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
High Temperature Testing ◽  
High Performance Fiber

scholarly journals Compressive Behavior Characteristics of High-Performance Slurry-Infiltrated Fiber-Reinforced Cementitious Composites (SIFRCCs) under Uniaxial Compressive Stress

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 159 ◽  
Author(s):  
Seungwon Kim ◽  
Seungyeon Han ◽  
Cheolwoo Park ◽  
Kyong-Ku Yun
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Compressive Stress ◽  
High Performance ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Behavior Characteristics

The compressive stress of concrete is used as a design variable for reinforced concrete structures in design standards. However, as the performance-based design is being used with increasing varieties and strengths of concrete and reinforcement bars, mechanical properties other than the compressive stress of concrete are sometimes used as major design variables. In particular, the evaluation of the mechanical properties of concrete is crucial when using fiber-reinforced concrete. Studies of high volume fractions in established compressive behavior prediction equations are insufficient compared to studies of conventional fiber-reinforced concrete. Furthermore, existing prediction equations for the mechanical properties of high-performance fiber-reinforced cementitious composite and high-strength concrete have limitations in terms of the strength and characteristics of contained fibers (diameter, length, volume fraction) even though the stress-strain relationship is determined by these factors. Therefore, this study developed a high-performance slurry-infiltrated fiber-reinforced cementitious composite that could prevent the fiber ball phenomenon, a disadvantage of conventional fiber-reinforced concrete, and maximize the fiber volume fraction. Then, the behavior characteristics under compressive stress were analyzed for fiber volume fractions of 4%, 5%, and 6%.

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