Mechanical Properties of Four High-Performance Concretes in Compression at High Temperatures

Cheyrezy, Marcel; Khoury, G. A.; Behloul, Mouloud

doi:10.1080/12795119.2001.9692343

Cited by 4 publications

(2 citation statements)

References 3 publications

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“…After completing 28 days of water curing, mortar specimens were withdrawn, dried, and then held in an electric furnace for required temperatures for 60 minutes, after turning off the furnace; specimens were annealed until the room temperature attained. After cooling, mass and strength of the specimens were measured (Koksal et al, 2015;Cheyrezy et al, 2001& Netinger et al, 2011. Initially, mortar specimens were exposed to higher temperature 900-1000 0 C (after literature review), but the specimens burst at high temperatures; thereby, temperature was restricted to 600 0 C after trials.…”

Section: Methodsmentioning

confidence: 99%

“…The increase in strength was due to expansion of moisture molecules that separate the C-S-H (calcium-silicate-hydrate) layer due to increase in temperature and weaken Vander Waal's physical forces within the cement composites. The moisture evaporation and reduction of distance between C-S-H gel layers result in enhancement in strength (Cheyrezy et al, 2001). The increase in strength may be due to acceleration of hydration process, while reduction was because of decomposition of cement paste (Khan and Abbas 2016).…”

Section: Change In Massmentioning

confidence: 99%

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Impact of high temperature on mortar mixes containing additives

Devi

Saini²,

Aggarwal³

2021

JER is an international, peer-reviewed journal that publishes f

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The structures may be exposed to fire or high temperature conditionally or accidentally. Alteration in the behavior of concrete structure is prospective under the exposure of elevated temperature. There is an urge to find the materials which can resist the alteration in physiochemical and strength properties of cementitious materials under high temperature. In the present study, the effect of elevated temperature on cement mortar consisting of additives i.e. accelerating admixtures, and stone waste i.e. stone slurry powder, was investigated and compared with specimens at room temperature. The aim of study was to examine the practicability of these additives under exposure to high temperatures. The mortar specimens were exposed to various temperatures i.e. 1500C, 3000C, 4500C and 6000C for the duration of one hour and compared with unheated samples. The change in mass, strength and micro-structure of mortar specimens at elevated temperature was studied. The environmental assessment and performance evaluation of various mortar mixes were also evaluated. The mass of mortar specimens reduced as the exposure temperature of specimens was raised. The residual strength of mortar increased up to a certain temperature afterward, it decreased. Stone slurry powder and calcium nitrate can be used individually and in combination to resist thermal changes.

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Section: Methodsmentioning

confidence: 99%

Section: Change In Massmentioning

confidence: 99%

Impact of high temperature on mortar mixes containing additives

Devi

Saini²,

Aggarwal³

2021

JER is an international, peer-reviewed journal that publishes f

View full text Add to dashboard Cite

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Transient thermal creep of concrete in service conditions at temperatures up to 300 °C

Colina

Sercombe

2004

Magazine of Concrete Research

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This paper presents experimental results concerning the behaviour of ordinary, high-strength and high-performance concretes under constant mechanical loading and increasing temperatures up to near 300°C. Heat was applied at a rate of 0·1 °C/min such that successive constant temperature levels were reached and maintained sufficiently to ensure internal temperature stabilisation. The analysis of experimental measures focuses on the so-called transient thermal creep, obtained during the transient thermal loading stages. To study the importance of changes in the internal properties, especially those related to free and bound water, some specimens were submitted to a second heating cycle. Test results confirm the existence of transient thermal strains during first heating, and its occurrence during the second cycle only when the maximum temperature of the first cycle was exceeded even if the specimen had spent a recovery period at ambient temperature. The transient thermal creep values were estimated for different temperature levels, above 105 °C, and they were inversely proportional to the water/cement ratio.

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Strain of heated concrete during two thermal cycles. Part 1: strain over two cycles, during first heating and at subsequent constant temperature

Khoury¹

2006

Magazine of Concrete Research

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This paper presents the strain behaviour of three nuclear reactor type plain unsealed (50–60 N/mm2) concretes exposed under 0% and 20% compressive loads to a 14-day two-thermal-cycle test (test temperatures ranging from 100°C to 600°C). A generic approach is taken for wider application and for the in-depth understanding of the behaviour of heated concrete in general. Concrete during the two thermal cycles experiences both expansive and contractive strains. The former includes ‘thermal expansion’, cracking expansion and chemically induced expansion. The latter includes drying shrinkage, load-induced thermal strain (LITS) during virgin heating, ‘delayed’ LITS at constant temperature and time-dependent creep. The overall strains during heating, at constant temperature and during cooling reflect both contractive and expansive influences. LITS is absent during cooling and a second heat cycle. A summary of the influences of material and environmental factors upon the thermal strain and LITS of concrete is given indicating first-order, second-order and negligible influences. The role of the thermal instability of concrete depends upon the constituents, and specifically the aggregate type. It is found to be very significant, manifesting itself in crack development and large expansive strains and is most evident when heating/cooling without load to temperatures above 300–400°C. A five-day period at constant temperature following the thermal transient (1°C/min) reveals shrinkage, creep and expansive strains dependent upon temperature–load level and concrete type, emanating from continuation of physico-chemical transformations. The largest strain contribution at constant temperature is from the end of the heating ramp (up to 10 h) to about one day after start of heating. The test regime provided a wider insight into the nature of heated concrete.

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Mechanical Properties of Four High-Performance Concretes in Compression at High Temperatures

Cited by 4 publications

References 3 publications

Impact of high temperature on mortar mixes containing additives

Impact of high temperature on mortar mixes containing additives

Transient thermal creep of concrete in service conditions at temperatures up to 300 °C

Strain of heated concrete during two thermal cycles. Part 1: strain over two cycles, during first heating and at subsequent constant temperature

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