Enhancing the accelerated carbonation of recycled concrete aggregates by using reclaimed wastewater from concrete batching plants

Fang, Xiaoliang; Zhan, Baojian; Poon, Chi Sun

doi:10.1016/j.conbuildmat.2019.117810

Cited by 50 publications

(13 citation statements)

References 33 publications

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“…Moreover, Figure 18 shows that carbonation led to an increase of pores of under 30 nm. Wang et al and Fang et al [40,54] reported the same finding. This is the range of pore sizes, in particular those under 10 nm, which made up the pores in the C-S-H gel.…”

Section: Changes In the Pore Size Distribution Of An Rca By Mercury Intrusion Porosimetrysupporting

confidence: 52%

“…The porosity in this range also decreased when the CO 2 concentration was increased to 100% (CO 2 uptake of 17.3 g/kg). This decrease was undoubtedly due to the clogging of pores by the formation of calcium carbonates during carbonation, which has been observed in both cement pastes [40,53,54] and RCAs [55]. The calcium carbonates that are formed accumulate and fill large pores.…”

Section: Changes In the Pore Size Distribution Of An Rca By Mercury Intrusion Porosimetrymentioning

confidence: 97%

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Improvement of Recycled Aggregates Properties by Means of CO2 Uptake

et al. 2021

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Concrete from deconstruction can have a second life in the form of recycled concrete aggregates (RCAs). They unfortunately have poor properties (high porosity and water absorption coefficient (WAC)) with respect to natural aggregates. Accelerated carbonation was implemented to improve the RCA properties and to increase their use by storing carbon dioxide (CO2) in the cement matrix and thereby reduce their environmental impact. This paper aims to perform a parametric study of a process for accelerated carbonation of RCAs to store the largest possible amount of CO2 and improve their properties. This study highlights the fact that each of these parameters affects CO2 storage, with an optimum water content for the maximum CO2 uptake depending on the nature and the source of the RCAs. This optimum is related to the RCA water absorption coefficient by a linear relationship. The results show that accelerated carbonation reduces the water absorption coefficient by as much as 67%. Finally, carbonation also decreases porosity, as observed by mercury intrusion porosimetry, by filling the capillary pores.

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Section: Changes In the Pore Size Distribution Of An Rca By Mercury Intrusion Porosimetrysupporting

confidence: 52%

Section: Changes In the Pore Size Distribution Of An Rca By Mercury Intrusion Porosimetrymentioning

confidence: 97%

Improvement of Recycled Aggregates Properties by Means of CO2 Uptake

et al. 2021

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“…The mechanical grinding of RCA causes the development of cracks and subsequent reduction in the performance of concrete with ground RCA 6 . Densification of the porous adhered to mortar results in increases in the strength of concrete 24–26 . In addition, the mechanical properties of the concrete made with the NCA and the concrete obtained by the substitution of NCA with RCA depend on the mixture proportioning.…”

Section: Introductionmentioning

confidence: 99%

“…6 Densification of the porous adhered to mortar results in increases in the strength of concrete. [24][25][26] In addition, the mechanical properties of the concrete made with the NCA and the concrete obtained by the substitution of NCA with RCA depend on the mixture proportioning. Three methods of RCA mixture design are the weight replacement method, equivalent mortar replacement method, and volume replacement method.…”

Section: Introductionmentioning

confidence: 99%

Performance assessment of recycled aggregate concrete and its variability

Gaurav

Kotoky

Jittin

et al. 2023

Structural Concrete

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The use of recycled aggregate improves waste management and is a crucial step toward the sustainable development of the concrete industry. Hence, this paper presents the experimental investigation to determine the mechanical properties of concrete with recycled concrete aggregates as the selective substitution for natural aggregates. The slump was observed to decrease by replacing natural coarse aggregates with recycled concrete aggregates. Compressive strength of about 40 MPa was achieved after 56 days of curing with the utilization of 100% recycled concrete aggregates. Besides, a reduction in the splitting tensile strength of 14% was observed due to the incorporation of recycled concrete aggregates. The statistical techniques use various probability distribution models such as Gamma, Lognormal, Weibull, and Normal distributions. Amongst the considered functions, lognormal and Weibull distributions best represent the experimentally obtained compressive strength of concrete with 100% natural aggregates and 50% recycled concrete aggregates, respectively. However, for concrete with 100% recycled aggregates, Weibull distribution represent compressive strength after 28 days of curing, and lognormal distribution is given the best fit for the compressive after 56 days of curing. In the case of split tensile strength, lognormal distribution provided the best representation after 56 days of curing for all specimens.

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“…High-tech carbonation methods have been proposed earlier in the literature [17], but such methods require significant investment and processing, which can reduce the competitiveness of the treated FRCA significantly. For example, provision of Ca + -rich wastewater has been shown to be effective in treating coarse RCA for reduced water absorption [18,19]. A similar approach for fine fractions seems possible, but consideration to differences in size and composition should be given.…”

Section: Introductionmentioning

confidence: 99%

Fine Recycled Concrete Aggregates Treated by Means of Wastewater and Carbonation Pretreatment

et al. 2023

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Fine recycled concrete aggregate (FRCA) possesses substantial limitations for its use due to its significant porosity. Extensive research on the effect of carbonation on the accessible porosity of coarse recycled concrete aggregate is available in the literature, but FRCA information is scarce. The present paper presents results of the effect of carbonation on different fractions of FRCA from <0.125 mm to 4 mm previously sprayed with wastewater from mortar production as an additional source of portlandite. The results of water absorption via the electrical conductivity method, TGA, XRD+Rietveld+PONKCS analysis, EDS mapping, and Life Cycle Assessment (LCA) demonstrate that the efficiency of the treatment depends on the particle size range of the FRCA. It was most effective for the extreme size fractions <0.25 mm and >1 mm of FRCA as a result of the relationship between the amount of precipitated calcium carbonate and the initially accessible porosity in each fraction. As a consequence, mortar produced with 30% replacement of natural sand with carbonated FRCA showed no impact on compressive strength.

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Enhancing the accelerated carbonation of recycled concrete aggregates by using reclaimed wastewater from concrete batching plants

Cited by 50 publications

References 33 publications

Improvement of Recycled Aggregates Properties by Means of CO2 Uptake

Improvement of Recycled Aggregates Properties by Means of CO2 Uptake

Performance assessment of recycled aggregate concrete and its variability

Fine Recycled Concrete Aggregates Treated by Means of Wastewater and Carbonation Pretreatment

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