scholarly journals STRAIN BEHAVIOUR OF ULTRA-HIGH-STRENGTH CONCRETE UNDER THE ELEVATED TEMPERATURE AND 0.25FCK LOADING

2016 ◽  
Author(s):  
Gyu Yong Kim ◽  
Young Wook Lee ◽  
Nenad Gucunski ◽  
Gyeong Cheol Choe ◽  
Min Ho Yoon
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
High Strength Concrete ◽  
Loading Condition ◽  
Elevated Temperatures ◽  
High Strength ◽  
Total Strain ◽  
High Temperature Creep ◽  
Temperature Creep ◽  
Strain Behaviour

The high-temperature creep of Ultra-High-Strength Concrete (UHSC) has been investigated in this study. The purpose of this study is to evaluated total strain and high-temperature creep at elevated temperatures under loading condition of UHSC. To evaluate the strain behaviour of UHSC at elevated temperatures, ϕ100 mm × 200 mm cylindrical specimens of UHSC with compressive strengths of 80, 130 and 180 MPa concrete were heated to 700 °C at a rate of 1 °C/min. The total strain and high-temperature-creep were measured under the loading condition of 0.25 of the compressive strength at room temperature. As results, Total strain of UHSC increased showing shrinkage with increasing compressive strength. The high-temperature creep of UHSC increased with the temperature and higher level of compressive strength showed bigger high-temperature creep.

scholarly journals Residual Compressive Strength of High-Strength Concrete Exposed to Elevated Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-22 ◽  
Author(s):  
Hussein M. Elsanadedy
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
High Strength ◽  
Strength Concrete ◽  
Residual Properties ◽  
Binder Ratio ◽  
Strength In Compression ◽  
Normal Strength

High-strength concrete (HSC) has several well-known technical, aesthetic, and economic advantages over normal-strength concrete (NSC), which explains the increasing popularity of the former material in the construction domain. As in the case of NSC, however, high temperature adversely affects HSC mechanical properties even more than in NSC, as indicated by the many studies performed so far on HSC at high temperature (hot properties) or past a thermal cycle at high temperature (residual properties). Since many code provisions concerning concrete properties versus high temperature were developed for ordinary concrete and the available models (in terms of stress-strain relationship) come mostly from the tests on NSC—as the tests on HSC are less numerous—developing predictive relationships for HSC exposed to high temperature is still an open issue, especially with reference to many parameters affecting concrete compressive strength, like temperature as such, heating rate, water-to-binder ratio, and strength in compression, to cite the most relevant parameters. To this purpose, a large database (more than 600 tests) is examined in this paper, which is focused on HSC residual properties and on the variables affecting its residual strength. Available design models from various guidelines, standards, codes, and technical reports are tested against the database, and new regression-based models and design formulae are proposed for HSC strength in compression, after the exposure to high temperature.

Effect of different fiber types on the mechanical properties of normal and high strength concrete at elevated temperatures

2021 ◽  
Vol 12 (1) ◽  
pp. 30
Author(s):  
Mohamed Amin ◽  
Khaled Abu el-hassan
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Fiber Types ◽  
Strength Concrete ◽  
Compressive And Flexural Strengths ◽  
Fiber Addition

The effects of the types of fibers on mechanical properties of normal and high strength concrete under high temperature, up to 700 °C, was investigated. Three different- type fiber; "Steel Fiber (SF), Glass Fiber (GF) and Polypropylene Fiber (PPF)" are added into the concretes in five different ratios (0, 0.50, 1.00, 1.50 and 2.0%)of the volume under the following temperatures; 22, 100, 400 and 700°C. The results indicate that all the different types of fibers researched contribute to both the compressive and flexural strengths of concrete under high temperature, however, it is also found that this contribution decreases with an increase in temperature. The flexural strengths and compressive strengths for NSC and HSC mixes at 28 days under high temperature decreases as the temperature increases especially up to 400°C. Also, the best compressive and flexural strengths performance under high temperature was also those of SF. The compressive strength of the concrete incorporating SF was reduced under high temperature only, while the mixes containing PPF and GF were reduced under high temperature or with fiber addition. The optimum fiber addition ratios of the mixes containing PPF and GF are between 0.5-1.0 percent by volume. And for SF, it is 1.5% by the volume.

scholarly journals Accelerated Creep Life Assessment of In-Service Power Plant Components

2019 ◽  
Vol 293 ◽  
pp. 03001
Author(s):  
Saud Hamad Aldajah ◽  
Mohammad Mazedul Kabir ◽  
Mohammad Y. Al-Haik
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Structural Integrity ◽  
Elevated Temperatures ◽  
Sem Analysis ◽  
Life Assessment ◽  
High Temperature Creep ◽  
Creep Life ◽  
Temperature Creep ◽  
Plant Components

Structural metals used in plant components are subject to aging from a combination of fatigue, creep, and corrosion. Exposure to elevated temperatures promotes creep. Aged metals lose toughness, or the ability to absorb energy at stress above the yield point and cannot endure an occasional high load without fracturing. Creep is one of the most critical factors for determining the structural integrity of components. The main objective of the current study is to assess the remaining creep life of various 20-year old power plant engineering components such as the high temperature fasteners. Due to time constraints, the approach followed in this study was to utilize the accelerated high temperature creep testing in addition to Scanning Electron Microscopy (SEM) analysis to assess the remaining life of 4 different samples. The accelerated high temperature creep tests were conducted at a stress level of 61 MPa and at a temperature of 1000°C for samples Sample 1 (original), Sample 2, Sample 3 and Sample 4; these samples were collected from different parts of the power plant. SEM analysis was carried out for all the samples. The results of the accelerated high temperature tests were compared to similar materials’ theoretical creep data using Larson Miller curve. The Larson Miller actual creep lives of the tested samples were much higher than the experimental ones, which suggest that the samples are critically aged. SEM analysis on the other hand, showed that all samples have high percentage of creep voids

scholarly journals Fire Performance of Heavyweight Self-Compacting Concrete and Heavyweight High Strength Concrete

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 822 ◽  
Author(s):  
Farhad Aslani ◽  
Fatemeh Hamidi ◽  
Qilong Ma
Keyword(s):  
Compressive Strength ◽  
Mass Loss ◽  
Modulus Of Elasticity ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
High Strength ◽  
Self Compacting Concrete ◽  
Strength Concrete ◽  
Magnetite Content ◽  
Hardened State

In this study, the fresh and hardened state properties of heavyweight self-compacting concrete (HWSCC) and heavyweight high strength concrete (HWHSC) containing heavyweight magnetite aggregate with 50, 75, and 100% replacement ratio, and their performance at elevated temperatures were explored experimentally. For fresh-state properties, the flowability and passing ability of HWSCCs were assessed by using slump flow, T500 mm, and J-ring tests. Hardened-state properties including hardened density, compressive strength, and modulus of elasticity were evaluated after 28 days of mixing. High-temperature tests were also performed to study the mass loss, spalling of HWSCC and HWHSC, and residual mechanical properties at 100, 300, 600 and 900 °C with a heating rate of 5 °C/min. Ultimately, by using the experimental data, rational numerical models were established to predict the compressive strength and modulus of elasticity of HWSCC at elevated temperatures. The results of the flowability and passing ability revealed that the addition of magnetite aggregate would not deteriorate the workability of HWSCCs and they retained their self-compacting characteristics. Based on the hardened densities, only self-compacting concrete (SCC) with 100% magnetite content, and high strength concrete (HSC) with 75 and 100% magnetite aggregate can be considered as HWC. For both the compressive strength and elastic modulus, decreasing trends were observed by introducing magnetite aggregate to SCC and HSC at an ambient temperature. Mass loss and spalling evaluations showed severe crack propagation for SCC without magnetite aggregate while SCCs containing magnetite aggregate preserved up to 900 °C. Nevertheless, the mass loss of SCCs containing 75 and 100% magnetite content were higher than that of SCC without magnetite. Due to the pressure build-up, HSCs with and without magnetite showed explosive spalling at high temperatures. The residual mechanical properties analysis indicated that the highest retention of the compressive strength and modulus of elasticity after exposure to elevated temperatures belonged to HWSCC with 100% magnetite content.

scholarly journals Behavior of High Strength Concrete Subjected to Elevated Temperature

2019 ◽  
Vol 9 (2) ◽  
pp. 2997-3000
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
High Strength ◽  
Air Cooling ◽  
Split Tensile Strength ◽  
Strength Concrete ◽  
Hardened Properties ◽  
Compressive Strength Of Concrete

The High strength concrete defined as per IS 456 as the concrete having characteristic compressive strength more than 65 MPa. The concrete when subject to fire i.e. elevated temperatures loses its properties at a rapid rate. In the present investigation, ordinary vibrated concrete of M90 grade was developed as per the IS 10262. The hardened properties of concrete like compressive strength and split tensile strength were determined for concrete at ordinary temperature. The concrete specimens were subjected to elevated temperatures of 400oC, 600 oC, and 800 oC and then the specimens were brought to room temperature under different cooling regimes like air cooling and water quenching. The compressive residual strength of concrete was determined and a typical compared was made with the control specimen. The decrease in compressive strength of concrete at 800 oC was high compared to that at 400 oC.

High-Temperature Compressive Strength of Steel Fiber High-Strength Concrete

2001 ◽  
Vol 13 (3) ◽  
pp. 230-234 ◽  
Author(s):  
Maria de Lurdes B. C. Reis ◽  
I. Cabrita Neves ◽  
A. J. B. Tadeu ◽  
João Paulo C. Rodrigues
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Strength Concrete ◽  
High Temperature Compressive Strength

MAGNESIUM EZ33A

Alloy Digest ◽  
1968 ◽  
Vol 17 (5) ◽  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Casting Alloy ◽  
High Temperature Creep ◽  
Chemical Company ◽  
Temperature Performance ◽  
Magnesium Casting ◽  
Metal Products

Abstract MAGNESIUM EZ33A is a magnesium casting alloy recommended for use at elevated temperatures. It has good high temperature creep strength up to about 500 F. This datasheet provides information on composition, physical properties, hardness, tensile properties, and compressive strength as well as fatigue. It also includes information on high temperature performance as well as casting, heat treating, machining, and joining. Filing Code: Mg-65. Producer or source: The Dow Chemical Company, Metal Products Department.

scholarly journals Physical and Mechanical Properties of High-Strength Concrete Modified with Supplementary Cementitious Materials after Exposure to Elevated Temperature up to 1000 °C

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 532 ◽  
Author(s):  
Jianwei Zhou ◽  
Dong Lu ◽  
Yuxuan Yang ◽  
Yue Gong ◽  
Xudong Ma ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Physical Properties ◽  
Water Absorption ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
High Strength ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Strength Concrete

This paper presents the experimental findings of a study on the influence of combining usage of supplementary cementitious materials (SCMs) on the performance of high-strength concrete (HSC) subjected to elevated temperatures. In this study, four types of HSC formulations were prepared: HSC made from cement and fly ash (FA), HSC made from cement and ultra-fine fly ash (UFFA), HSC made from cement and UFFA-metakaolin (MK), and HSC made from cement and FA-UFFA-MK. Mechanical and physical properties of HSC subjected to high temperatures (400, 600, 800, and 1000 °C) were studied. Furthermore, the relation between residual compressive strength and physical properties (loss mass, water absorption, and porosity) of HSC was developed. Results showed that the combined usage of SCMs had limited influence on the early-age strength of HSC, while the 28-d strength had been significantly affected. At 1000 °C, the residual compressive strength retained 18.7 MPa and 23.9 MPa for concretes containing 30% UFFA-5% MK and 10% FA-20% UFFA-5% MK, respectively. The specimen containing FA-UFFA-MK showed the best physical properties when the temperature raised above 600 °C. Combined usage of SCMs (10% FA-20% UFFA-5% MK) showed the lowest mass loss (9.2%), water absorption (10.9%) and porosity (28.6%) at 1000 °C. There was a strongly correlated relation between residual strength and physical properties of HSC exposed to elevated temperatures.

scholarly journals Effect of Thermal Properties of Aggregates on the Mechanical Properties of High Strength Concrete under Loading and High Temperature Conditions

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6093
Author(s):  
Taegyu Lee ◽  
Keesin Jeong ◽  
Hyeonggil Choi
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Thermal Properties ◽  
High Temperature ◽  
High Strength Concrete ◽  
Room Temperature ◽  
Thermal Strain ◽  
High Strength ◽  
Transient Creep ◽  
Lightweight Aggregates

The effect of the thermal properties of aggregates on the mechanical properties of high-strength concrete was evaluated under loading and high-temperature conditions. For the concrete, granite was selected as a natural aggregate, and ash-clay and clay as lightweight aggregates. The mechanical properties of the concrete (stress–strain, compressive strength, elastic modulus, thermal strain, and transient creep) were evaluated experimentally under uniform heating from 20 to 700 °C while maintaining the load at 0, 20, and 40% of the compressive strength at room temperature. Experimental results showed that the concrete containing lightweight aggregates had better mechanical properties, such as compressive strength and elastic modulus, than that of the concrete with a granite aggregate at high temperature. In particular, the concrete containing lightweight aggregates exhibited high compressive strength (60–80% of that at room temperature) even at 700 °C. Moreover, the concrete containing granite exhibited a higher thermal strain than that containing lightweight aggregates. The influence of the binding force under loaded conditions, however, was found to be larger for the latter type. The transient creep caused by the loading was constant regardless of the aggregate type below 500 °C but increased more rapidly when the coefficient of the thermal expansion of the aggregate was above 500 °C.

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