Steel Ring-Based Restraint of HSC Explosive Spalling in High Temperature Environments

2014 ◽  
Vol 5 (3) ◽  
pp. 239-250 ◽  
Author(s):  
Toru Tanibe ◽  
Mitsuo Ozawa ◽  
Ryota Kamata ◽  
Keitetsu Rokugo
Keyword(s):  
Thermal Stress ◽  
Vapor Pressure ◽  
High Strength Concrete ◽  
Rapid Heating ◽  
Heated Surface ◽  
High Strength ◽  
Heating Time ◽  
Explosive Spalling ◽  
Heating Curve ◽  
Support Estimation

This paper reports on an experimental study regarding the behavior of restrained high-strength concrete in response to the type of extreme heating associated with fire. The study was intended to support estimation of thermal stress from the strain in a restraining steel ring and vapor pressure in restrained concrete under the conditions of a RABT 30 rapid heating curve. The size of the specimens was φ300 X 100 mm, and the results showed that explosive spalling occurred between 4 and 10 minutes in terms of heating time. It was also observed that the thermal stress was greater than the vapor pressure value of 0.1 MPa at a point 10 mm from the heated surface at 5 minutes. The maximum spalling depth was about 61 mm. It was inferred that spalling behavior caused by thermal stress may become predominant under restrained conditions.

Effects of Silica Fume Addition on the Spalling Phenomena of Reactive Powder Concrete

2012 ◽  
Vol 174-177 ◽  
pp. 1090-1095 ◽  
Author(s):  
Kai Pei Tian ◽  
Yang Ju ◽  
Hong Bin Liu ◽  
Jin Hui Liu ◽  
Li Wang ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Vapor Pressure ◽  
Silica Fume ◽  
High Strength Concrete ◽  
High Strength ◽  
Reactive Powder Concrete ◽  
Spalling Resistance ◽  
Explosive Spalling ◽  
Strength Concrete ◽  
Reactive Powder

The explosive spalling of high-strength concrete due to fire is a problem that has garnered increasingly widespread attention, particularly the explosive spalling of reactive powder concrete (RPC). For years, based on the vapor pressure mechanism, the addition of fibers has been demonstrated to be somewhat effective in protecting against spalling. However, relevant experiments indicate that fibers are not effective for dense concrete, which is a challenge for the simple vapor pressure mechanism in providing spalling resistance for RPC. The authors found that silica fume plays an important role in the explosive spalling of RPC. Thus, four classes of RPCs with different ratios of silica fume were prepared, and the spalling phenomena and the inner temperature distribution during heating were investigated. The results show that silica fume content has a prominent effect on the spalling process of RPC.

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

Fire Resistance of Ultra-High-Strength Concrete: a Review

2011 ◽  
Vol 477 ◽  
pp. 333-339 ◽  
Author(s):  
Gai Fei Peng ◽  
Yan Teng
Keyword(s):  
Fire Resistance ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Loss ◽  
Engineering Practice ◽  
Explosive Spalling ◽  
Strength Concrete ◽  
Normal Strength ◽  
Reactive Powder ◽  
Near Future

This paper presents a review of advances in research on fire resistance of high-strength concrete (HSC) and ultra-high-strength concrete (UHSC). Further research needs in the near future on UHSC, especially on reactive powder concrete (RPC), are also discussed. It is commonly recognized that HSC suffers strength loss in a manner basically similar to that of normal strength concrete. But the main problem of HSC is explosive spalling under high temperature, which can be solved by employing either polymer fiber or steel fiber. Since RPC200 is a type of RPC which has been successfully prepared in many counties and is to be applied to engineering practice, fire resistance of RPC200 needs a series of investigations urgently. The objectives of such investigations are to restrain explosive spalling and minimizing spalling probability, so as to ensure satisfactory fire resistance of RPC. It is expected that a research will be carried out on explosive spalling behavior, fracture properties, and micro-structure, to establish a mechanism as well as technical measures for improving fire resistance of RPC.

Effect of Types and Contents of Polymer Resin on Spalling Prevention of High-Strength Concrete Subjected to Fire

2011 ◽  
Vol 466 ◽  
pp. 85-95 ◽  
Author(s):  
Cheon Goo Han ◽  
Min Cheol Han ◽  
Chan Chun Pei ◽  
Seong Hwan Yang
Keyword(s):  
Compressive Strength ◽  
Melting Point ◽  
High Strength Concrete ◽  
Polyvinyl Acetate ◽  
High Strength ◽  
Slight Reduction ◽  
Explosive Spalling ◽  
Strength Concrete ◽  
Polymer Resin ◽  
Acetate Copolymer

In this study, the fundamental and spalling properties of high-strength concrete were examined, especially when various types and varying content of polymer resin were added. Two types of polymers were used in this study: ethylene vinyl acetate copolymer (EVA-P) and polyvinyl acetate copolymer (PVA-P) as powders and polyvinyl acetate copolymer (PVA-F) and polypropylene copolymer (PP-F) as fibers. Test results showed that the addition of EVA-P and PVA-F to concrete slightly decreased flowability, whereas the addition of PP-F and PVA-P enhanced the viscosity, leading to a remarkable reduction in flowability. The air content of concrete containing EVA-P, PVA-F, and PP-F showed no significant variation. The addition of PVA-P to concrete also caused a slight reduction in compressive strength, whereas the other additives had insignificant effects. After a fire test, the control concrete and concretes with EVA-P, PVA-P, and PVA-F exhibited severe explosive spalling regardless of the dosages. This was because the polymer does not provide sufficient void networks, which is important for vapor evacuation, which enables the release of steam pressure inside the concrete. However, when more than 0.10% of PP-F was added, spalling was effectively prevented. For the residual compressive strength, higher polymer dosage in the concrete produced better results regardless of the polymer type. The powder-type polymers did not contribute to preventing spalling in concrete subjected to fire. This is due to their geometric shape and high melting point. It is concluded that a high aspect ratio and low melting point is critical during polymer selection to prevent spalling in high-strength concrete.

Analysis of Post-Combustion High-Strength Concrete Compressive Strength Using Polypropylene Fibers

2020 ◽  
Vol 26 (1) ◽  
pp. 118-127
Author(s):  
Teuku Budi Aulia ◽  
Muttaqin Muttaqin ◽  
Mochammad Afifuddin ◽  
Zahra Amalia
Keyword(s):  
Compressive Strength ◽  
Thermal Stress ◽  
Silica Fume ◽  
High Temperatures ◽  
High Strength Concrete ◽  
High Strength ◽  
Polypropylene Fibers ◽  
Concrete Compressive Strength ◽  
Strength Concrete ◽  
Maximum Value

High-strength concrete is vulnerable to high temperatures due to its high density. The use of polypropylene fibers could prevent structure explosion by forming canals due to melted fibers during fire, thus release its thermal stress. This study aims to determine the effect of polypropylene fibers on compressive strength of high-strength concrete after combustion at 400ºC for five hours. High-strength concrete was made by w/c-ratio 0.3 with cement amount 550 kg/m3 and added with silica fume 8% and superplasticizer 4% by cement weight. The variations of polypropylene fibers were 0%, 0.2% and 0.4% of concrete volume. The compression test was carried out on standard cylinders Ø15/30 cm of combustion and without combustion specimens at 7 and 28 days. The results showed that compressive strength of high-strength concretes without using polypropylene fibers decreased in post-combustion compared with specimens without combustion, i.e., 0.81% at 7 days and 23.42% at 28 days. Conversely, the use of polypropylene fibers can increase post-combustion compressive strength with a maximum value resulted in adding 0.2% which are 25.52% and 10.44% at 7 and 28 days respectively. It can be concluded that the use of polypropylene fibers is effective to prevent reduction of high-strength concrete compressive strength that are burned at high temperatures.

scholarly journals STUDY ON EXPLOSIVE SPALLING PROCESS OF HIGH-STRENGTH CONCRETE BY MEANS OF ACOUSTIC EMISSION

2009 ◽  
Vol 65 (1) ◽  
pp. 16-29
Author(s):  
Mitsuo OZAWA ◽  
Shinya UCHIDA ◽  
Ruping WANG ◽  
Toshiro KAMADA ◽  
Hiroaki MORIMOTO
Keyword(s):  
Acoustic Emission ◽  
High Strength Concrete ◽  
High Strength ◽  
Explosive Spalling ◽  
Strength Concrete

Reliability Analysis of High-Strength Concrete Columns during a Fire

2014 ◽  
Vol 629-630 ◽  
pp. 273-278 ◽  
Author(s):  
Jian Zhuang Xiao ◽  
Qing Hai Xie ◽  
Yi Zhao Hou ◽  
Zhi Wei Li
Keyword(s):  
Reliability Analysis ◽  
Fire Resistance ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
Axial Loading ◽  
High Strength ◽  
Concrete Columns ◽  
Explosive Spalling ◽  
Strength Concrete ◽  
High Strength Concrete Columns

A reliability analysis was conducted on high-strength concrete (HSC) columns during a fire. The influences of fire’s randomness and explosive spalling of concrete were investigated. The fire resistance for axial loading capacity of HSC columns was in terms of steel yield strength and concrete compressive strength with considering the effect of elevated temperatures. The load random variables included dead load and sustained live load. The JC method was applied to calculate the reliability index of the fire resistance of axially loaded HSC columns. It was found that the randomness of fire and explosive spalling of concrete had a significant influence on reliability of HSC columns.

On the Properties of Ultra High Strength Concrete With Particular Reference to Heat of Hydration

1984 ◽  
Vol 42 ◽  
Author(s):  
Leif Aarsleff ◽  
Jorn Bredal-Jorgensen ◽  
Ervin Poulsen
Keyword(s):  
Thermal Stress ◽  
Cross Section ◽  
High Strength Concrete ◽  
High Strength ◽  
Heat Of Hydration ◽  
Compression Tests ◽  
Thin Sections ◽  
Strength Concrete ◽  
Penetration Tests ◽  
Cement Compounds

AbstractIt has been observed that the heat of hydration for concrete under practical conditions not only depends on the type of cement and the content of cement and silica fume in the concrete but also depends on the w/c-ratio of the concrete. On.microscopic examination of concrete having low w/c-ratio it has been observed that the cement compounds are left partly unhydrated. However, the unhydrated cement compounds exist for all values of the w/c-ratio, but appear to increase with decreasing value of the w/c-ratio, particularly when w/c < 0.35.This fact wIll influence the present way of estimating the heat of hydration when a thermal stress analysis is to be carried out for an ultra high strength concrete in order to prevent the concrete from crackling due to temperature differences across a massive cross-section.The tests are carried out with concrete having a compression strength greater than 100 MPa (∼ 14,000 psi). In order to obtain samples drilled from the same casting for compression tests, microscopic investigatlon, penetration tests and freezing/thawing-investigation rather large specimens are used. A very effective insulation of the concrete is provided, and the temperature of the concrete is recorded by thermo-couples.The structure of the cement paste is studied using petrographical examination of thin-sections and polished samples. The tests on penetration and freezing/thawing are not dealt with in this paper.

The Mechanism of Explosive Spalling and Measures to Resistant Spalling of Concrete Exposed to High Temperature by Incorporating Fibers: A Review

2010 ◽  
Vol 168-170 ◽  
pp. 773-777 ◽  
Author(s):  
Juan Yang ◽  
Gai Fei Peng
Keyword(s):  
High Strength Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Hybrid Fiber ◽  
Explosive Spalling ◽  
Preliminary Study ◽  
Experimental Researches

Many experimental researches have been conducted on explosive spalling performance of concrete of high-strength / high performance concrete (HSC/HPC). This paper summarizes two main explosive spalling mechanisms (Vapor pressure build-up mechanism and Thermal stress mechanism) of concrete at elevated temperature, and also presents the measures to resistant the explosive spalling, i.e. by incorporating fibers (polypropylene fiber(PPF), steel fiber(SF) and hybrid fiber of the first two). Finally, the further studies of both the mechanism and the measures are proposed. Also, the preliminary study of ultra high-strength concrete (UHSC) on fire-resistance are mentioned.

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