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

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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Influences of Glassified Micro-Bubble on Mechanical Properties of Ultra-High-Strength Concrete after Exposure to High Temperature

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.629-630.259 ◽

2014 ◽

Vol 629-630 ◽

pp. 259-264

Author(s):

Gai Fei Peng ◽

Xiao Li Wang ◽

Lin Wang

Keyword(s):

Mechanical Properties ◽

Experimental Investigation ◽

High Temperature ◽

High Strength Concrete ◽

Room Temperature ◽

High Strength ◽

Strength Concrete ◽

Micro Bubble ◽

Residual Mechanical Properties ◽

Tensile Splitting Strength

An experimental investigation was conducted to study residual mechanical properties of Ultra-High-Strength concrete with different dosages of glassified micro-bubble after exposure to high temperature. After exposure to different target temperatures (room temperature, 200 °C, 400 °C, 600 °C,800 °C), residual mechanical properties (residual compressive strength, residual tensile splitting strength, residual fracture energy) of Ultra-High-Strength concrete under different conditions including 1 water-binder ratios (0.18), 3 different contents of glassified micro-bubble (0%, 40%, 60%) were all investigated. The effect of different dosage of glassified micro-bubble was studied on residual mechanical properties of Ultra-High-Strength concrete after exposure to high temperature. The results indicate that the variations of different kinds of Ultra-High-Strength concrete with different dosage of glassified micro-bubble are basically the same. With the increase of temperature, the residual mechanical properties increase at first, then decrease. The residual mechanical properties decrease after exposure to high temperature of 800 °C.

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Reduction of Postfire Properties of High-Strength Concrete

Advances in Materials Science and Engineering ◽

10.1155/2013/712953 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 6

Author(s):

Neno Torić ◽

Ivica Boko ◽

Bernardin Peroš

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

High Temperature ◽

Ambient Temperature ◽

Modulus Of Elasticity ◽

High Strength Concrete ◽

High Strength ◽

Maximum Temperature ◽

Secant Modulus ◽

Strength Concrete

This paper presents an experimental study of behaviour of high-strength concrete at high temperature. Reduction of the mechanical properties of concrete was determined starting from the period when the concrete specimens were heated to the maximum temperature and cooled down to ambient temperature and the additional 96 hours after the initial cooling of the specimens. The study includes determination of compressive strength, dynamic and secant modulus of elasticity, and stress-strain curves of concrete specimens when exposed to temperature level up to 600°C. The study results were compared with those obtained from other studies, EN 1994-1-2 and EN 1992-1-2. Tests point to the fact that compressive strength of concrete continues to reduce rapidly 96 hours after cooling of the specimens to ambient temperature; therefore indicating that the mechanical properties of concrete have substantial reduction after being exposed to high temperature. The study of the dynamic and secant modulus of elasticity shows that both of the properties are reduced but remain constant during the period of 96 hours after cooling. The level of postfire reduction of compressive strength of the analyzed concrete is substantial and could significantly affect the postfire load bearing capacity of a structure.

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Comparison Analysis on the Mechanical Properties of HSC and NSC after the Action of High Temperatures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1014.49 ◽

2014 ◽

Vol 1014 ◽

pp. 49-52

Author(s):

Xiao Ping Su

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

High Temperatures ◽

High Strength Concrete ◽

Elasticity Modulus ◽

Strain Curve ◽

Peak Stress ◽

High Strength ◽

Peak Strain ◽

Strength Concrete

With the wide application of high strength concrete in the building construction,the risk making concrete subject to high temperatures during a fire is increasing. Comparison tests on the mechanical properties of high strength concrete (HSC) and normal strength concrete (NSC) after the action of high temperature were made in this article, which were compared from the following aspects: the peak stress, the peak strain, elasticity modulus, and stress-strain curve after high temperature. Results show that the laws of the mechanical properties of HSC and NSC changing with the temperature are the same. With the increase of heating temperature, the peak stress and elasticity modulus decreases, while the peak strain grows rapidly. HSC shows greater brittleness and worse fire-resistant performance than NSC, and destroys suddenly. The research and evaluation on the fire-resistant performance of HSC should be strengthened during the structural design and construction on the HSC buildings.

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Deterioration of Mechanical Properties of High-Strength Pumpcrete after Exposure to High Temperatures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.168-170.564 ◽

2010 ◽

Vol 168-170 ◽

pp. 564-569

Author(s):

Guang Lin Yuan ◽

Jing Wei Zhang ◽

Jian Wen Chen ◽

Dan Yu Zhu

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Heating Rate ◽

High Strength Concrete ◽

Heating Temperature ◽

High Strength ◽

Air Cooling ◽

Test Results ◽

Strength Deterioration ◽

Residual Compressive Strength

This paper makes an experimental study of mechanical properties of high-strength pumpcrete under fire, and the effects of heating rate, heating temperature and cooling mode on the residual compressive strength(RCS) of high-strength pumpcrete are investigated. The results show that under air cooling, the strength deterioration speed of high-strength concrete after high temperature increases with the increase of concrete strength grade. Also, the higher heating temperature is, the lower residual compressive strength value is. At the same heating rate (10°C/min), the residual compressive strength of C45 concrete after water cooling is a little higher than that after air cooling; but the test results are just the opposite for C55 and C65 concrete. The strength deterioration speed of high-strength concrete after high temperature increases with the increase of heating rate, but not in proportion. And when the heating temperature rises up between 200°C and 500°C, heating rate has the most remarkable effect on the residual compressive strength of concrete. These test results provide scientific proofs for further evaluation and analysis of mechanical properties of reinforced-concrete after exposure to high temperatures.

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Effect of High Temperature on Concrete: A Literature Review

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.302-303.138 ◽

2006 ◽

Vol 302-303 ◽

pp. 138-149 ◽

Cited By ~ 4

Author(s):

Gai Fei Peng ◽

Sammy Yin Nin Chan ◽

Qi Ming Song ◽

Quan Xin Yi

Keyword(s):

Experimental Data ◽

Mechanical Properties ◽

High Temperature ◽

Elevated Temperature ◽

Literature Review ◽

High Strength Concrete ◽

High Strength ◽

Research Needs ◽

Standard Fire ◽

Fire Condition

This paper presents a review on the effect of fire on concrete, citing 43 references. It was found that most of them are on the behavior of concrete under high temperature conditions more or less different from the standard fire condition. The problem of spalling, which high-strength concrete encounters when exposed to fire, is especially urgent to solve. Since the literature on the behavior of concrete under fire conditions is very limited, the literature even under elevated temperature has to be used as a part of the base of further research. The further research needs urgently to be carried out under the standard fire condition. Residual mechanical properties reported in most previous literature might be overestimated, where natural cooling was usually employed. Proper evaluation of fire resistance of concrete needs more experimental data obtained under various cooling regimes such as water spraying or water quenching.

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Effect of Locally Available Wheat Straw Ash in Developing High Strength Concrete

Journal of Engineering Research and Reports ◽

10.9734/jerr/2021/v21i717476 ◽

2021 ◽

pp. 19-28

Author(s):

Muhammad Armaghan Siffat ◽

Muhammad Ishfaq ◽

Afaq Ahmad ◽

Khalil Ur Rehman ◽

Fawad Ahmad

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Wheat Straw ◽

High Strength Concrete ◽

High Strength ◽

Optimum Temperature ◽

X Ray Diffraction ◽

X Ray ◽

Strength Concrete ◽

Straw Ash

This study is supervised to assess the characteristics of the locally available wheat straw ash (WSA) to consume as a substitute to the cement and support in enhancing the mechanical properties of concrete. Initially, after incineration at optimum temperature of 800°C for 0.5, the ash of wheat straw was made up to the desirable level of fineness by passing through it to the several grinding cycles. Subsequently, the X-ray fluorescence (XRF) along with X-ray diffraction (XRD) testing conducted on ash of wheat straw for the evaluation its pozzolanic potential. Finally, the specimens of concrete were made by consuming 10% and 20% percentages of wheat straw ash as a replacement in concrete to conclude its impact on the compressive strength of high strength concrete. The cylinders of steel of dimensions 10cm diameter x 20cm depth were acquired to evaluate the compressive strength of high strength concrete. The relative outcomes of cylinders made of wheat straw ash substitution presented the slight increase in strength values of the concrete. Ultimately, the C-100 blends and WSA aided cement blends were inspected for the rheology of WSA through FTIR spectroscopy along with Thermogravimetric technique. The conclusions authenticate the WSA potential to replace cement in the manufacturing of the high strength concrete.

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Strength Characteristics of High Strength Concrete (HSC) with and without Coarse Aggregate

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.b5131.129219 ◽

2019 ◽

Vol 9 (2) ◽

pp. 4701-4704

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Fly Ash ◽

Flexural Strength ◽

Silica Fume ◽

High Strength Concrete ◽

Mechanical Characteristics ◽

Coarse Aggregate ◽

High Strength ◽

Set Up

This paper aimed to investigate the mechanical characteristics of HSC of M60 concrete adding 25% of fly ash to cement and sand and percentage variations of silica fumes 0%,5% and 10% to cement with varying sizes of 10mm,6mm,2mm and powder of granite aggregate with w/c of 0.32. Specimens are tested for compressive strength using 10cm X 10cmX10cm cubes for 7,14,28 days flexural strength was determined by using 10cmX10cmX50cm beam specimens at 28 days and 15cm diameter and 30cm height cylinder specimens at 28 days using super plasticizers of conplast 430 as a water reducing agent. In this paper the experimental set up is made to study the mechanical properties of HSC with and without coarse aggregate with varying sizes as 10mm, 6mm, 2mm and powder. Similarly, the effect of silica fume on HSC by varying its percentages as 0%, 5% and 10% in the mix studied. For all mixes 25% extra fly ash has been added for cement and sand.

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Effect of Hot Processing on Mircrostructure and Properties of Flat Billets of TA15 Titanium Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1016.906 ◽

2021 ◽

Vol 1016 ◽

pp. 906-910

Author(s):

Xin Hua Min ◽

Cheng Jin

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Titanium Alloy ◽

High Temperature ◽

Room Temperature ◽

High Strength ◽

Slow Cooling ◽

Microstructure And Mechanical Properties ◽

Ta15 Titanium Alloy ◽

The Ideal

In this paper,effect of the different forging processes on the microstructure and mechanical properties of the flat flat billets of TA15 titanium alloy was investigated.The flat billiets of 80 mm×150 mm×L sizes of TA15 titanium alloy are produced by four different forging processes.Then the different microstrure and properties of the flat billiets were obtained by heat treatment of 800 °C~850 °C×1 h~4h.The results show that, adopting the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling, the primary αphases content is just 10%, and there are lots of thin aciculate phases on the base. This microstructure has both high strength at room temperature and high temperature, while the properties between the cross and lengthwise directions are just the same. So the hot processing of the first forging temperature at T1 °C、slow cooling and the second forging temperature at T2°C 、quick cooling is choosed as the ideal processing for production of aircraft frame parts.

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A Study on the Thermal Properties of High-Strength Concrete Containing CBA Fine Aggregates

Materials ◽

10.3390/ma13071493 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1493 ◽

Cited By ~ 1

Author(s):

In-Hwan Yang ◽

Jihun Park

Keyword(s):

Thermal Conductivity ◽

Compressive Strength ◽

Thermal Properties ◽

Ultrasonic Velocity ◽

High Strength Concrete ◽

High Strength ◽

Unit Weight ◽

Test Results ◽

Strength Concrete ◽

Fine Aggregates

The thermal conductivity of concrete is a key factor for efficient energy consumption in concrete buildings because thermal conductivity plays a significant role in heat transfer through concrete walls. This study investigated the effects of replacing fine aggregates with coal bottom ash (CBA) and the influence of curing age on the thermal properties of high-strength concrete with a compressive strength exceeding 60 MPa. The different CBA aggregate contents included 25%, 50%, 75%, and 100%, and different curing ages included 28 and 56 days. For concrete containing CBA fine aggregate, the thermal and mechanical properties, including the unit weight, thermal conductivity, compressive strength, and ultrasonic velocity, were measured. The experimental results reveal that the unit weight and thermal conductivity of the CBA concrete were highly dependent on the CBA content. The unit weight, thermal conductivity, and compressive strength of the concrete decreased as the CBA content increased. Relationships between the thermal conductivity and the unit weight, thermal conductivity and compressive strength of the CBA concrete were proposed in the form of exponential functions. The equations proposed in this study provided predictions that were in good agreement with the test results. In addition, the test results show that there was an approximately linear relationship between the thermal conductivity and ultrasonic velocity of the CBA concrete.

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