scholarly journals Spalling Resistance of Fiber-Reinforced Ultra-High-Strength Concrete Subjected to the ISO-834 Standard Fire Curve: Effects of Thermal Strain and Water Vapor Pressure

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3792
Author(s):  
Taegyu Lee ◽  
Gyuyong Kim ◽  
Gyeongcheol Choe ◽  
Euichul Hwang ◽  
Jaesung Lee ◽  
...  
Keyword(s):  
High Strength Concrete ◽  
Pore Formation ◽  
Water Vapor Pressure ◽  
Thermal Strain ◽  
High Strength ◽  
Strength Concrete ◽  
Standard Fire ◽  
Fire Curve ◽  
Standard Fire Curve ◽  
Polyethylene Fibers

The prevention and mitigation of spalling in high-strength concrete (HSC) rely on mixing polypropylene (PP) as an additive reinforcement. The dense internal structures of ultra-high-strength concrete (UHSC) result in risks associated with a high thermal stress and high water vapor pressure. Herein, the effects of pore formation and thermal strain on spalling are examined by subjecting fiber-laden UHSC to conditions similar to those under which the ISO-834 standard fire curve was obtained. Evaluation of the initial melting properties of the fibers based on thermogravimetric analysis (TGA) and differential thermal analysis (DTA) demon strated that although nylon fibers exhibit a higher melting point than polypropylene and polyethylene fibers, weight loss occurs below 200 °C. Nylon fibers were effective at reducing spalling in UHSC compared to polypropylene and polyethylene fibers as they rapidly melt, leading to pore formation. We anticipate that these results will serve as references for future studies on the prevention of spalling in fiber-reinforced UHSC.

Water Vapor Pressure and Spalling Properties of High Strength Concrete Restrained by Steel-Ring

2018 ◽  
Vol 30 (6) ◽  
pp. 617-624
Author(s):  
Jae-Wook Baek ◽  
Gyu-Yong Kim ◽  
Jeong-Soo Nam ◽  
Eui-Chul Hwang ◽  
Gyeong-Cheol Choe ◽  
...  
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
High Strength Concrete ◽  
Water Vapor Pressure ◽  
High Strength ◽  
Strength Concrete

Thermal strain behavior and strength degradation of ultra-high-strength-concrete

2015 ◽  
Vol 49 (8) ◽  
pp. 3411-3421 ◽  
Author(s):  
Young Wook Lee ◽  
Gyu Yong Kim ◽  
Nenad Gucunski ◽  
Gyeong Choel Choe ◽  
Min Ho Yoon
Keyword(s):  
High Strength Concrete ◽  
Thermal Strain ◽  
High Strength ◽  
Strength Degradation ◽  
Strength Concrete ◽  
Strain Behavior

scholarly journals Experimental evaluation of colored HSC column in fire conditions

2013 ◽  
Vol 3 (1) ◽  
pp. 39-54
Author(s):  
C. Britez ◽  
P. Castro-Borges ◽  
A. Berto ◽  
P. Helene
Keyword(s):  
Iron Oxide ◽  
High Strength Concrete ◽  
High Strength ◽  
Experimental Program ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Strength Concrete ◽  
Standard Fire ◽  
In Fire ◽  
Fire Conditions

ABSTRACTIn recent times it has been common to associate high-strength concrete with a greater susceptibility to explosive type spalling, when subjected to high temperatures. In part, this doubt is a result of some experimental programs that are carried out on small unreinforced concrete samples (specimens), which could substantially influence the structural concrete behavior in fire conditions. This paper presents an experimental program, carried out in Brazil on a high strength colored reinforced concrete column (HSCC), eight years-old, fc,8years = 140MPa, basalt coarse aggregate, cross section of 700mm x 700mm, tested under no load and with three faces exposed to standard fire curve ISO 834 for 180min (3h). The results demonstrated, in this case, that HSCC maintained integrity under experimental fire and that the iron oxide pigments can work as an excellent natural thermometer, contributing to the evaluation of the structure post-fire simulation.Keywords: High-strength concrete; fire resistance; colored concrete; column in fire; iron oxide pigment. RESUMENHa sido común asociar el concreto de alta resistencia con una mayor susceptibilidad al desprendimiento por explosión (spalling) cuando se le somete a altas temperaturas. Esta duda se debe en parte a los resultados de algunos programas experimentales que se han llevado a cabo en pequeñas probetas de concreto simple sin refuerzo, lo que puede influir sustancialmente en el comportamiento del concreto en situación de incendio. Este artículo presenta un programa experimental en Brasil donde un pilar de concreto armado colorido de alta resistencia (HCAR), con ocho años de edad, fc,8años = 140MPa, árido grueso basáltico, sección cuadrada de 700mm x 700mm, fue ensayado sin carga y con tres lados expuestos al fuego (curva ISO 834) durante 180min (3h). Los resultados demostraron en este caso que el HCAR se mantuvo íntegro y que los pigmentos de óxido de hierro pueden trabajar como excelente termómetro natural, contribuyendo en la evaluación de la estructura después de la simulación de incendio.Palabras Clave: Concreto de alta resistencia; resistencia al fuego; concreto colorido; pilar sometido al fuego; pigmento de óxido de hierro. 

Performance of high-strength concrete walls exposed to fire

2017 ◽  
Vol 21 (8) ◽  
pp. 1173-1182 ◽  
Author(s):  
Kate TQ Nguyen ◽  
Tuan Ngo ◽  
Priyan Mendis ◽  
David Heath
Keyword(s):  
High Strength Concrete ◽  
Elevated Temperatures ◽  
Compressive Load ◽  
High Strength ◽  
Hardened Concrete ◽  
Normal Strength Concrete ◽  
Concrete Walls ◽  
Strength Concrete ◽  
Standard Fire ◽  
Normal Strength

High-strength concrete is becoming very popular around the world due to its many advantages over normal-strength concrete. There are significant behavioural differences between high-strength concrete and normal-strength concrete, most notably the brittleness and sudden spalling under elevated temperatures, whereby pieces of hardened concrete explosively dislodge. Although all high-rise and even many medium-rise buildings have high-strength concrete walls, the spalling of high-strength concrete walls in fire has generally been ignored by the designers and the fire resistance of walls has been calculated using the rules specified for normal-strength concrete. Catastrophic failures could occur due to this ignorance of an important issue. Major design codes including the American and Australian Codes do not cover spalling adequately. Even the Eurocode rules are based on limited research. After a brief discussion on the present design practice, this article presents a summary of spalling research. The relevant results from a comprehensive study conducted at the University of Melbourne are briefly discussed. The authors are not aware of any other comprehensive research projects covering the fire behaviour of normal-strength concrete and high-strength concrete walls exposed not only to standard fires but also hydrocarbon fires. The results showed that spalling in high-strength concrete is more significant when subjected to hydrocarbon fire compared to normal-strength concrete. The level of compressive load on the panels was also found to have a significant effect on the fire performance of the high-strength concrete panels. The finite analysis element program, ANSYS, was used to model the concrete walls subjected to load and fire (both ISO834 Standard fire and hydrocarbon fire). The test results were used to validate the computer model.

Study on Strength Development of High Strength Concrete Containing Alccofine and Fly-Ash

2012 ◽  
Vol 2 (3) ◽  
pp. 102-104 ◽  
Author(s):  
Suthar Sunil B ◽  
◽  
Dr. (Smt.) B. K. Shah Dr. (Smt.) B. K. Shah
Keyword(s):  
Fly Ash ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Development ◽  
Strength Concrete
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