Recycled concrete exposed to high temperatures

Zega, Claudio Javier; Maio, Ángel Antonio Di

doi:10.1680/macr.2006.58.10.675

Cited by 100 publications

(46 citation statements)

References 2 publications

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“…As Zega and Di Maio [34,35] explained, the Coefficient of Thermal Expansion (CTE) of the old/new mortar interface was perceived to be comparable and its compatibility reduced micro/macro cracking of the cement mortars. But after exposure to 800ºC, the concretes made with FA and GGBS apparently had lower residual strength than that of the Portland cement concretes, probably as a consequence of the coarsening of the pore structure.…”

Section: Compressive Strengthmentioning

confidence: 99%

“…According to Zega and Di Maio [34,35] high temperature performance of RAC prepared with low w/c ratios were better than that of conventional concretes. The coefficient of Thermal Expansion (CTE) of the old/new mortar interface was perceived to be comparable and its compatibility reduced micro/macro cracking of the cement mortars.…”

Section: Introductionmentioning

confidence: 96%

“…With respect to the aggregates, common aggregates remain stable up 500ºC. Quartz expands by approximately 5.7% in volume at 570ºC [42,43] and limestone decomposes at 600-900ºC [44].…”

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Residue strength, water absorption and pore size distributions of recycled aggregate concrete after exposure to elevated temperatures

Kou

Poon

Etxeberria

2014

Cement and Concrete Composites

111

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Section: Compressive Strengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 1 more Smart Citation

Residue strength, water absorption and pore size distributions of recycled aggregate concrete after exposure to elevated temperatures

Kou

Poon

Etxeberria

2014

Cement and Concrete Composites

111

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“…For example, an earlier work [15] studied the residual compression strength of concrete prepared with natural coarse granite aggregates and concrete containing 75% by volume of coarse RCA. The samples were heated to 500°C and soaked for 1 and 4 h followed by a slow oven cooling to room temperature.…”

Section: Introductionmentioning

confidence: 99%

Fire Performance of Sustainable Recycled Concrete Aggregates: Mechanical Properties at Elevated Temperatures and Current Research Needs

et al. 2015

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The materials used for the construction of buildings are changing. There are now many sustainability drivers for developing novel green construction materials. An emerging material used for building construction is concrete with conventional coarse aggregates substituted as recycled concrete aggregates (RCA). This is a form of sustainable concrete. A finite number of buildings (>10) with this material have been constructed in North America, Europe and Asia. However; to help facilitate wide spread use and development of sustainable concrete with RCA, there is purpose in considering this material's at-elevated temperature (in-fire) mechanical properties. To date, this topic has seen limited research attention as it is difficult to study. The study herein considered the mechanical properties of conventional and sustainable concrete with RCA. The only difference between the conventional and the sustainable concrete mixes was the mass proportion of a conventional natural coarse aggregate, Limestone, which had been substituted with coarse RCA (at replacement proportions of 0%, 30% and 100%). Both the ambient and elevated temperature mechanical properties were considered with compressive mechanical tests using an innovative optical technology for strain measurement. Based on the analysis performed, a proportional decrease in retained strength and elasticity of concrete at-elevated temperature with increasing RCA content was observed. For example both mechanical properties showed a 0.2% decrease in retained value for every 1% RCA increase at 500°C. In addition the modelling parameter of Poisson ratio appeared to be influenced by the heat imposed and the aggregate type contained within the concrete. For example at 500°C, this parameter showed an 73% increase for concrete samples with only Limestone aggregate and a 15% decrease for samples with only RCA (of mixed origin primarily Siliceous). This paper concludes with highlighting current knowledge gaps and research needs that when addressed could help improve the facilitation of using sustainable concrete's with RCA in construction of buildings.

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“…When the temperature reaches 600°C, the hydration product calcium-silicate-hydrate, which is responsible for the strength of the cement, is destroyed. Besides this, the cement paste shrinks and a significant decrease in strength occurs [6,[10][11][12]. When the temperature reaches 800°C, it's about to breakdown of the concrete completely and further the concrete is going to be disintegrated [5, 13 and 14].…”

Section: Introductionmentioning

confidence: 99%

Yüksek Sıcaklığa Maruz Uçucu Kül İçeren Betonun Ultrases Geçiş Hızı ve Basınç Dayanımının Değerlendirilmesi

Erdoğdu¹,

Kandil²,

Nas³

et al. 2017

Nevşehir Bilim Ve Teknoloji Dergisi

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Concrete is frequently subjected to various adverse environmental effects throughout its service life such as fire and high temperature. Although the resistance of concrete against fire is superior to many other construction materials up to a certain temperature, its performance starts to decrease at temperatures above 400 o C. Serious physical and mechanical damage starts to take place particularly above 400 o C and the performance of concrete decreases due to such impacts.Fly ash is an artificial pozzolanic material that can be used as a mineral additive in making concrete. Fly ash has on the one hand a beneficial effect on the performance of the concrete and allows economy by saving cement on the other hand as it is a waste product of thermal power plants.In this study, the compressive strength and ultrasonic pulse velocities of concrete containing fly ash subjected to high temperatures was investigated. The measurements were taken at the end of 28 days of standard curing and 28 days of standard curing plus 90 days of air curing in a laboratory condition. Concretes of 300 kg/m 3 were produced and fly ash was replaced with cement at ratios of 20%, 30% and 40% by weight of cement. The ultrasonic and compressive strengths measurements were taken on 100 mm cubes.The It has been found that fly ash substitution does not have a beneficial effect on concrete subjected to high temperature both in ultrasonic pulse velocity and compressive strength.Keywords: High temperature, fly ash, ultrasonic pulse velocity, compressive strength. Yüksek Sıcaklığa Maruz Uçucu Kül İçeren Betonun Ultrases Geçiş Hızı ve Basınç Dayanımının Değerlendirilmesi ÖzBeton servis ömrü boyunca yangın ve yüksek sıcaklık ve benzeri çeşitli olumsuz çevresel etkilere maruz kalır. Betonun yangına karşı direnci belirli bir sıcaklığa kadar diğer birçok yapı malzemesinden daha üstündür. 400 o C`nin üzerindeki sıcaklıklarda ciddi fiziksel ve mekanik hasarlar oluşmaya başlar ve bu etkiler nedeniyle betonun performansı düşer.Uçucu kül beton üretiminde mineral katkı olarak kullanılan yapay puzolanik bir malzemedir. Uçucu kül kullanımı betonun performansı üzerinde olumlu bir etki oluştururken termik santrallerin atık bir ürünü olduğu için betonda kullanılması ekonomik ve çevrecidir.Bu çalışmada, yüksek sıcaklığa maruz kalmış uçucu kül içeren betonun basınç dayanımı ve ultrases geçiş hızı araştırılmıştır. Uçucu kül ikamesinin yüksek sıcaklığa maruz betonun hem ultrases geçiş hızı hem de basınç dayanımına olumlu bir etki sağlamadığı görülmüştür.

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Recycled concrete exposed to high temperatures

Cited by 100 publications

References 2 publications

Residue strength, water absorption and pore size distributions of recycled aggregate concrete after exposure to elevated temperatures

Residue strength, water absorption and pore size distributions of recycled aggregate concrete after exposure to elevated temperatures

Fire Performance of Sustainable Recycled Concrete Aggregates: Mechanical Properties at Elevated Temperatures and Current Research Needs

Yüksek Sıcaklığa Maruz Uçucu Kül İçeren Betonun Ultrases Geçiş Hızı ve Basınç Dayanımının Değerlendirilmesi

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