Effect of incorporation of high volume of recycled concrete aggregates and fly ash on the strength and global warming potential of concrete

Kurad, Rawaz; Silvestre, José Dinis; Brito, Jorge de; Ahmed, Hawreen

doi:10.1016/j.jclepro.2017.07.236

Cited by 260 publications

(104 citation statements)

References 65 publications

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“…Consequently, the FA particles can easily reach the Ca(OH) 2 of RCA. The reasons behind these trends are explained in previous studies [20,29,36]. Table 3.…”

Section: Strengthmentioning

confidence: 65%

“…As shown in [28], the target workability of the concrete mixes (S2) was kept constant by maintaining the effective water-to-cement ratio. Further details regarding the mix compositions, the raw materials used, and the standards followed are shown in previous studies [20,28,29]. …”

Section: Mechanical Strengthmentioning

confidence: 99%

“…These trends were expected because it is well-known that SP increases the mechanical performance of concrete, and both FA and RCA are harmful above a given incorporation ratio. Additionally, a high volume of coarse RCA in concrete is less detrimental than that of fine RCA, but much less favorable than the incorporation of FA [20,29,36]. Although the mechanical behaviour of concrete is essential, ranking concrete mixes based only on their strength may not be reliable from a "business as usual" point of view.…”

Section: Strengthmentioning

confidence: 99%

“…Also, the life cycle assessment [20][21][22][23][24], toxicity [25], and economy [26,27] of concrete mixes made with both FA and RCA have been investigated. However, the knowledge related to the combined effects of high volumes of FA and RCA from a mechanical and economic point view is still very scarce.…”

Section: Introductionmentioning

confidence: 99%

“…To date, the characteristics of concrete containing high volume of fly ash (FA) [4][5][6][7], recycled concrete aggregate (RCA) [8][9][10][11][12][13][14][15], and both FA and RCA [16][17][18][19][20] have been studied in terms of quality. Also, the life cycle assessment [20][21][22][23][24], toxicity [25], and economy [26,27] of concrete mixes made with both FA and RCA have been investigated. However, the knowledge related to the combined effects of high volumes of FA and RCA from a mechanical and economic point view is still very scarce.…”

Section: Introductionmentioning

confidence: 99%

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Combined Economic and Mechanical Performance Optimization of Recycled Aggregate Concrete with High Volume of Fly Ash

Brito

Silvestre

2018

Applied Sciences

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Featured Application: This study provides a tool to help the construction sector to choose the most cost-efficient concrete mixes made with alternative sustainable materials, according to the target application.Abstract: This study intends to evaluate high and low-strength concrete mixes made with high volume of fly ash (FA) and recycled concrete aggregates (RCA) from both a mechanical and economic point of view. For this purpose, the mechanical characteristics of concrete, namely compressive strength (f cm ), splitting tensile strength (f ctm ), and modulus of elasticity (E cm ) were correlated with the cost of 1 m 3 of concrete mixes, taking into account the most common scenarios (e.g., cost of the raw materials, transportation between supplier and concrete plant, and mixing procedure) in the centre of Portugal. The results show that the incorporation of FA and RCA are detrimental to the mechanical properties of concrete. E cm is predominantly influenced by RCA, and "f cm " and "f ctm " are mainly controlled by FA incorporation. However, after a given age, the rate of the strength development (f cm , f ctm and E cm ) of RCA concrete containing FA significantly accelerates over time relative to the reference concrete (without FA and RCA) and to the mixes made with either RCA or FA. Furthermore, the cost of concrete does not significantly change by incorporating RCA. The use of superplasticizer (SP) significantly increases the cost of concrete. However, the higher cost of concrete due to the use of SP can be offset by replacing cement with FA. Regarding the optimization process, concrete mixes with the lowest cost may not necessarily be the optimum choice regarding cost efficiency. In fact, the mechanical properties of concrete also need to be considered to aid the decision on the optimal concrete mix. Finally, the results show that the optimum mixes in terms of cost and mechanical characteristics are mostly the ones made with simultaneous incorporation of RCA, FA, and SP, rather than with their individual incorporation.

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“…Consequently, the FA particles can easily reach the Ca(OH) 2 of RCA. The reasons behind these trends are explained in previous studies [20,29,36]. Table 3.…”

Section: Strengthmentioning

confidence: 65%

Section: Mechanical Strengthmentioning

confidence: 99%

Section: Strengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Combined Economic and Mechanical Performance Optimization of Recycled Aggregate Concrete with High Volume of Fly Ash

Brito

Silvestre

2018

Applied Sciences

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Combined influence of nano‐CaCO₃ and polyvinyl alcohol fibers on fresh and mechanical performance of concrete incorporating fly ash

Zhang

Zheng

Wang

et al. 2019

Structural Concrete

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In this investigation, the combined influence of polyvinyl alcohol (PVA) fibers and nano-CaCO 3 particles on fresh and mechanical performance of concrete containing fly ash was assessed. In the concrete, Portland cement was replaced with 1, 2, 3, and 4% (by weight) of nano-CaCO 3 . PVA fibers were added to the concrete at a dosage of 0.05, 0.10, 0.15, and 0.2% (by volume). The flowability of the fresh concrete was assessed using slump and slump flow measurements. The mechanical properties of the concrete evaluated included compressive and flexural strength as well as elastic modulus under both compression and flexure conditions. Our results showed that the workability of the concrete decreased with increases in nano-CaCO 3 and PVA fiber content. When the dosage of nano-CaCO 3 was no more than 3%, the flexural and compressive elastic modulus, flexural, and compressive strength of the concrete increased with nano-CaCO 3 content. However, these mechanical property values decreased when the dosage of nano-CaCO 3 increased from 3 to 4%. When the fiber content was less than 0.15%, the compressive and flexural strength and elastic modulus of the concrete increased with fiber content. However, these values began to decrease as the PVA fiber dosage increased from 0.15 to 0.2%. K E Y W O R D Sfiber-reinforced concrete, mechanical properties, nano-CaCO 3 , PVA fiber, workability

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Reliability‐based recommendations for EN1992 carbonation cover design of concrete with coarse recycled concrete aggregates

Albuquerque

Pacheco

Brito

2022

Structural Concrete

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Research argues in favor of using recycled aggregates in structural concrete.However, lack of specific clauses in standards for recycled aggregate concrete design hinders the use of recycled aggregate concrete by the industry. Recycled aggregate concrete-specific design clauses are hindered because conventional research must be complemented with experiments directed towards stochastic modeling, so that reliability concepts may evaluate whether the probabilities of failure of design comply with the expectations of Society or whether specific design rules are needed. This article compares the within-batch variability of carbonation under accelerated conditions of four natural aggregate concrete and four analogue recycled aggregate concrete mixes and analyses the reliability of Eurocode 2 cover design for carbonation exposure. In general, the incorporation of coarse recycled concrete aggregates worsened the mean durability behavior of concrete, including resistance to carbonation. However, the variability of carbonation depth was not meaningfully affected by the recycled aggregates used (coarse recycled aggregates produced from concrete waste) and the reliability of concrete cover design only decreased due to the effect of the recycled aggregates on the mean resistance to carbonation. A 5 mm increase of concrete cover was found to more than offset the detrimental influence of full incorporation of recycled aggregates on the reliability of concrete cover design.

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Effect of incorporation of high volume of recycled concrete aggregates and fly ash on the strength and global warming potential of concrete

Cited by 260 publications

References 65 publications

Combined Economic and Mechanical Performance Optimization of Recycled Aggregate Concrete with High Volume of Fly Ash

Combined Economic and Mechanical Performance Optimization of Recycled Aggregate Concrete with High Volume of Fly Ash

Combined influence of nano‐CaCO₃ and polyvinyl alcohol fibers on fresh and mechanical performance of concrete incorporating fly ash

Reliability‐based recommendations for EN1992 carbonation cover design of concrete with coarse recycled concrete aggregates

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Effect of incorporation of high volume of recycled concrete aggregates and fly ash on the strength and global warming potential of concrete

Cited by 260 publications

References 65 publications

Combined Economic and Mechanical Performance Optimization of Recycled Aggregate Concrete with High Volume of Fly Ash

Combined Economic and Mechanical Performance Optimization of Recycled Aggregate Concrete with High Volume of Fly Ash

Combined influence of nano‐CaCO3 and polyvinyl alcohol fibers on fresh and mechanical performance of concrete incorporating fly ash

Reliability‐based recommendations for EN1992 carbonation cover design of concrete with coarse recycled concrete aggregates

Contact Info

Product

Resources

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Combined influence of nano‐CaCO₃ and polyvinyl alcohol fibers on fresh and mechanical performance of concrete incorporating fly ash