Effects of elevated temperature on performance of recycled coarse aggregate concrete

Salahuddin, Hammad; Nawaz, Adnan; Maqsoom, Ahsen; Mehmood, Tahir; Zeeshan, Badar ul Ali

doi:10.1016/j.conbuildmat.2019.01.011

Cited by 82 publications

(25 citation statements)

References 18 publications

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“…Only the reduction in the HSMs produced with 5% CDT is higher than that of the control HSMs at this temperature. The decrease in the U w values of the HSMs from 400 to 600°C can be explained by the decomposition of Ca(OH) 2 to its components 50–52 . At 800°C, the U w value of the control HSM decreases at a rate of 11.5% with respect to their unheated condition.…”

Section: Resultsmentioning

confidence: 98%

“…The intensities of all the XRD peaks of the HSM samples decrease gradually with the increasing of temperature. The dehydration of Ca(OH) 2 at temperatures above 400°C 50–52 and decomposition of CSH gel at temperatures above 600°C 48,57 are mainly caused by the decrease of the XRD peaks in the HSMs. Generally, the XRD peaks of the control HSMs at 800 and 1,000°C are again actually coincident with those of the HSMs produced with 10 and 20% CDT.…”

Section: Resultsmentioning

confidence: 99%

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Influence of calcined diatomite content and elevated temperatures on the properties of high strength mortars produced with basalt sand

Sarıdemir

Çelıkten

Çiflikli

et al. 2020

Structural Concrete

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In this paper, the effect of calcined diatomite (CDT) content on the mechanical, microstructural, and mineralogical properties of high strength mortars (HSMs) exposed to 25, 400, 600, 800, and 1,000°C temperatures is investigated. The percentages of CDT that replace Portland cement (PC) in this work are 0, 5, 10, 15, and 20%, by weight. The researched properties of the HSMs are the unit weight (Uw), ultrasonic pulse velocity (Upv), flexural strength (fs), compressive strength (fc) and the analyses of X‐ray powder diffraction, polarized light microscopy, and scanning electron microscopy/energy dispersive spectroscopy. The experimental results show that the CDT has a potential to be successfully employed as a partial replacement of PC in the HSMs exposed to elevated temperatures. The optimal replacement level of PC by CDT is determined as 15% from strength tests. Besides, the Uw, Upv, fs, and fc values progressively reduce as the temperatures subjected to the HSMs increase. The CDT has a positive effect on the fs and fc values the HSMs after exposure to elevated temperatures.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Influence of calcined diatomite content and elevated temperatures on the properties of high strength mortars produced with basalt sand

Sarıdemir

Çelıkten

Çiflikli

et al. 2020

Structural Concrete

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show abstract

“…Other studies have not found the replacement percentage to have a significant impact [23,36,39,44]. Furthermore, in some recent studies [35,40,41] RACs exhibited greater reductions in compressive strength at high temperatures than their counterpart control concretes containing natural aggregates.…”

Section: Introductionmentioning

confidence: 91%

“…Regarding the compressive strength tests, many studies did not report the respective standards according to which the tests were conducted. Nonetheless, the EN 12390-3 standard was used in [23,31], the ASTM C 39 was used in [22,24,27,39,41], the GB/T 50081-2002 was used in [32,40] and the BS 1881-116 was used in [28].…”

Section: Introductionmentioning

confidence: 99%

Residual Compressive Strength of Recycled Aggregate Concretes after High Temperature Exposure

et al. 2020

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Sustainability requirements are gaining importance in the construction industry, which needs to take specific measures in the design and construction of concrete structures. The use of recycled aggregates in concrete may be of special interest. Recycling a construction waste will close the life cycle of the original materials (e.g., concrete). Thus, environmental benefits would come from the lower waste generation, and from a lower necessity of raw materials for new structures. The current Spanish code for structural concrete considers the use of recycled aggregates in replacement rates up to 20% by aggregate mass, assimilating their properties with those of concretes without aggregate replacement. Higher substitution percentages would require further testing. In this work, substitution of coarse aggregate for recycled aggregates (with replacement percentages of 25%, 50% and 100%) has been studied, and the concrete’s residual properties after exposure to high temperatures (between 350 °C and 850 °C) have been assessed. Compressive strength and capillary water absorption tests were made after heating, and the experiments showed higher residual strength in concretes with the greatest content of recycled aggregates. However, a statistical analysis made with additional data available in the literature seemed to predict otherwise, and the recycled aggregate replacement would have a negative effect on the residual strength.

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“…The literature survey expresses that there have been many studies that have utilized different pozzolanic materials like silica-fume [ 17 ], fly-ash, ground granulated blast furnace slag, and other waste materials as a partial replacement of cement to produce sustainable concrete with a better microstructure and improved performance [ 18 , 19 , 20 , 21 , 22 ]. Moreover, the use of different waste materials, including the C & D waste as a coarse aggregate replacement [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ], and as a substitute for fine aggregates in the conventional concrete [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ] as well as in RPC [ 40 ], has also been reported. Sand obtained from river mining is one of the main elements of RPC, which is used as a filler [ 41 ].…”

Section: Introductionmentioning

confidence: 99%

Elevated Temperature Performance of Reactive Powder Concrete Containing Recycled Fine Aggregates

Salahuddin

Qureshi²,

Nawaz

et al. 2020

Materials

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This study examines the effect of elevated temperature on various properties of reactive powder concrete (RPC) containing varying percentages of recycled fine aggregates as sand replacement. Recycled fine aggregates were collected from two sources, i.e., demolished normal strength concrete and demolished RPC. The specimens were prepared using 25%, 50%, and 75% replacement of natural sand with recycled fine aggregates, exposed to two different curing conditions and were subjected to four temperatures, i.e., 25, 200, 400, and 600 °C. Later, the specimens were tested for mass loss, compressive strength test, split-tensile strength test, flexural strength test, and water absorption test at all temperature ranges. Results determined that although the mechanical properties degraded with the temperature rise, the recycled aggregates can be employed as a partial replacement of natural sand in RPC without causing a significant decrease in the performance of RPC, and can help to produce more sustainable RPC by using recycled aggregates.

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Effects of elevated temperature on performance of recycled coarse aggregate concrete

Cited by 82 publications

References 18 publications

Influence of calcined diatomite content and elevated temperatures on the properties of high strength mortars produced with basalt sand

Influence of calcined diatomite content and elevated temperatures on the properties of high strength mortars produced with basalt sand

Residual Compressive Strength of Recycled Aggregate Concretes after High Temperature Exposure

Elevated Temperature Performance of Reactive Powder Concrete Containing Recycled Fine Aggregates

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