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

Zaccardi, Yury Villagrán; Broodcoorens, Lotte; Heede, Philip Van den; Belie, Nele De

doi:10.3390/su15086386

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…The selective separation hence addresses the need to remove the adhered cement paste from aggregates in an economically feasible way [9,49]. It enables the complete recycling of old concrete back to concrete and cement production and thus significantly contributes to its sustainability [4].…”

Section: Discussionmentioning

confidence: 99%

Recycled Sand and Aggregates for Structural Concrete: Toward the Industrial Production of High-Quality Recycled Materials with Low Water Absorption

Skocek,

Ouzia,

Vargas Serrano

et al. 2024

Sustainability

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Concrete recycling to produce aggregates is crucial in reducing the demand for virgin materials in the construction industry, particularly for the most widely used building material—concrete. A potential solution to enhance the quality of recycled aggregates involves the removal of the adhered cement paste from their surfaces. In this study, samples of industrial demolished concrete were selectively separated into recycled sands and aggregates while removing the hydrated cement paste. The recycled materials were characterized to assess their suitability for structural concrete production. The behavior and underlying mechanisms of recycled sands and aggregates proved to be identical, irrespective of their size. Water absorption emerged as a key parameter for evaluating the purity and quality of these materials. The statistical analysis revealed that when the water absorption of recycled aggregates and sand falls below 5%, the compressive strength may, at most, decrease by 15% (97.5% confidence) at any replacement level. Consequently, they can entirely replace virgin materials without a significant negative impact on fresh or hardened concrete properties at a constant cement content. Concrete samples with recycled materials had comparable workability, strength, and durability characteristics to references with virgin materials. The production of high-quality recycled aggregates and sand can facilitate complete concrete recycling and hence significantly contribute to virgin materials preservation, thus making concrete more sustainable.

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Section: Discussionmentioning

confidence: 99%

Recycled Sand and Aggregates for Structural Concrete: Toward the Industrial Production of High-Quality Recycled Materials with Low Water Absorption

Skocek,

Ouzia,

Vargas Serrano

et al. 2024

Sustainability

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“…The reduction in porosity may be a prevailing physical effect over the chemical effect of reduced buffer capacity. Several authors [ 46 , 47 , 48 , 49 , 55 , 58 , 60 , 61 , 62 , 63 ] described the improved microstructure of mineral carbonated RCA. The reduction in porosity was confirmed in both the attached mortar and the old ITZ and reflected in an overall increased performance [ 54 , 64 , 65 , 66 ].…”

Section: Influencing Factors In Carbonation Ratementioning

confidence: 99%

Unraveling the Interplay of Physical-Chemical Factors Impacting the Carbonation Performance of Recycled Aggregate Concrete

Pico-Cortés,

Villagrán-Zaccardi

2023

Materials

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Recycled aggregate concrete (RAC) includes recycled concrete aggregates (coarse and/or fine) as substitutes for natural aggregates as an approach to achieving a circular economy. Some concerns remain about its performance, including the carbonation resistance. The higher porosity of recycled concrete aggregates is logically a disadvantage, but the analysis must address many other factors. This paper provides an in-depth examination of recent advances in the carbonation performance of RAC. The emphasis is on factors that influence CO2 diffusion and the carbonation rate, e.g., the replacement ratio, source concrete quality, interfacial transition zone features, residual portlandite content, and porosity. The influences of previous treatments, combined action with supplementary cementitious materials, and loading conditions are also discussed. The replacement ratio has a significant impact on the carbonation performance of concrete, but it is also dependent on other factors. During carbonation, the physical effects of the porosity of the aggregate and the physical–chemical effects of the portlandite content in the adhered mortar are particularly important. The residual portlandite is especially significant because it is the primary hydration product responsible for the alkaline reserve for carbonation and the potential pozzolanic reaction, which are per se competing factors that determine the carbonation rate.

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Carbonation mechanism and cementation properties of recycled cement paste based on CO2 injection time and pressure

Yang,

Piao,

Zhu

et al. 2024

Construction and Building Materials

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

Cited by 5 publications

References 24 publications

Recycled Sand and Aggregates for Structural Concrete: Toward the Industrial Production of High-Quality Recycled Materials with Low Water Absorption

Recycled Sand and Aggregates for Structural Concrete: Toward the Industrial Production of High-Quality Recycled Materials with Low Water Absorption

Unraveling the Interplay of Physical-Chemical Factors Impacting the Carbonation Performance of Recycled Aggregate Concrete

Carbonation mechanism and cementation properties of recycled cement paste based on CO2 injection time and pressure

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