Effect of Aggregate Size on Recycled Aggregate Concrete under Equivalent Mortar Volume Mix Design

Jang, Haneol; Kim, Jeonghyun; Sičáková, Alena

doi:10.3390/app112311274

Cited by 20 publications

(10 citation statements)

References 48 publications

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“…On the other hand, for RFA, the results of previous studies have reported that fine aggregate in the SSD state was more favorable to the mechanical strength of concrete than in the air-dry and oven-dry state [ 36 , 37 ]. Therefore, NCA, NFA, and RFA were used in the SSD state, and partially saturated RCA dried at room temperature 24 h before mixing after complete saturation was used [ 38 ].…”

Section: Methodsmentioning

confidence: 99%

An Experimental Study on Structural Concrete Containing Recycled Aggregates and Powder from Construction and Demolition Waste

2022

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For complete utilization of construction and demolition (C&D) waste, an investigation of all size fractions of C&D waste generated during the recycling process should be conducted. In this work, the effects of three recycled concrete materials with different sizes (recycled coarse aggregate (RCA) with a size of 4.75–25 mm, recycled fine aggregate (RFA) of 0.15–4.75 mm, and recycled powder (RP) smaller than 0.15 mm) produced from concrete waste on the fresh and hardened mechanical properties of concrete were evaluated. The replacement ratios of natural coarse and fine aggregates by RCA and RFA were 30, 60, and 100%, and those of ordinary Portland cement for RP were 10, 20, and 30%. The results showed that the concrete properties deteriorated with increasing replacement ratio regardless of the type of recycled materials. The properties were reduced in the order of the use of RFA, RCA, and the simultaneous use of RCA and RFA. In addition, concrete with 30% RP showed lower mechanical strength than concrete with 100% RCA and 100% RFA. However, all concretes could be applicable for structural purposes under different environmental exposure conditions. In particular, concretes with 10% RP and 20% RP showed better cost-benefits compared to natural aggregate concrete with 100% ordinary Portland cement. These promising findings provide valuable initiatives for the effective and complete recycling of C&D waste.

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Section: Methodsmentioning

confidence: 99%

An Experimental Study on Structural Concrete Containing Recycled Aggregates and Powder from Construction and Demolition Waste

2022

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“…As the adhesive mortar content of RCA increased with the number of recycling cycles, the amount of cement, sand, and water required for unit concrete decreased in the order of R1, R2, and R3. A detailed description of the mix proportions of concrete designed with the EMV method can be found in our previous studies [ 23 , 24 ].…”

Section: Experimental Programmentioning

confidence: 99%

Influence of Mix Design on Physical, Mechanical and Durability Properties of Multi-Recycled Aggregate Concrete

et al. 2023

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The decrease in the quality of recycled aggregate due to an increase in the number of recycling is a primary factor that limits the multi-recycling of concrete. This degradation adversely affects concrete performance; thus, the characteristics of recycled aggregate should be considered during the mix design stage, but little research has taken that into account. This study investigates the effect of the equivalent mortar volume (EMV) mix design on some physical, mechanical and durability properties of concrete made of multiple recycled coarse aggregates at 50% and 100% replacement ratios compared to concrete made by the conventional mix design (CMD). The results showed that the performances of concrete by the CMD decreased with an increasing number of recycling cycles. The properties of EMV-based concrete deteriorated with an increase in the number of recycling cycles at 100% replacement ratio due to poor workability caused by a shortage of fresh mortar. However, at 50% replacement, the EMV-based concrete exhibited similar performance across the three cycles of recycling, as well as improved properties over natural aggregate concrete. This study demonstrated that an appropriate mix design and optimal aggregate replacement ratio can offset the property loss of multiple recycled aggregate concrete.

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“…This intricate relationship underscores the importance of understanding Agronomy 2024, 14, 899 2 of 18 the structural attributes of soil aggregates, as they profoundly influence the stability of SOC. One pivotal metric utilized for assessing this stability is the mean weight diameter (MWD) [5]. A higher MWD value signifies enhanced aggregate stability, reflecting the effectiveness of soil aggregation in storing and preserving SOC.…”

Section: Introductionmentioning

confidence: 99%

Enhancing Soil Aggregate Stability and Organic Carbon in Northwestern China through Straw, Biochar, and Nitrogen Supplementation

Wu,

Teng,

Zhong

et al. 2024

Agronomy

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Enhancing soil stability through the incorporation of straw and biochar is well documented. Nevertheless, the combined impact of straw, biochar, and nitrogen supplementation on soil aggregates and organic carbon still needs to be explored, with limited attention given to various sieving methods in the existing literature. Therefore, the current experiment used four sieving methods—routine wet sieving (RoutW), fast-wetting sieving (FastW), slow-wetting sieving (SlowW), and wetting–stirring sieving (WetS)—to investigate the effects of adding straw (0 or 4.5 t ha−1), biochar (from maize straw, 0 or 15 t ha−1), and N (0 or 100 kg ha−1) on soil aggregate stability and soil organic C in silt–loam soil of rainfed farmland in northwest China. The field experiment was started in 2014; soil samples were collected in 2021. The results revealed that straw returned, biochar, and N addition significantly increased soil mean weight diameter (MWD) and soil organic C (SOC). Compared to CN0 (zero-amendment) plots, straw returned with nitrogen addition (SN100) significantly increased the MWD of aggregates by 130.3% (RoutW), 121.66% (FastW), 73.94% (SlowW), and 91.78% (WetS) in the 0–30 cm soil layer. The addition of biochar and nitrogen (BN100) treatment showed the most significant effects on the relative slaking index (RSI), relative mechanical breakdown index (RMI), and SOC; compared with CN0 treatment, BN100 plots can reduce RSI and RMI by 42.90% and 54.66% and increase SOC by 53.27% for all soil layers. Therefore, adding organic materials with N can enhance the stability of soil aggregates and SOC of silt–loam soils in northwest China. Integrating biochar as an organic soil amendment in the agricultural practices of northwest China presents a multifaceted solution that addresses soil health, crop productivity, and environmental sustainability. The current study provides valuable insights that support adopting this innovative approach, paving the way for future sustainable agricultural practices that can benefit both the region and the global community.

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Effect of Aggregate Size on Recycled Aggregate Concrete under Equivalent Mortar Volume Mix Design

Cited by 20 publications

References 48 publications

An Experimental Study on Structural Concrete Containing Recycled Aggregates and Powder from Construction and Demolition Waste

An Experimental Study on Structural Concrete Containing Recycled Aggregates and Powder from Construction and Demolition Waste

Influence of Mix Design on Physical, Mechanical and Durability Properties of Multi-Recycled Aggregate Concrete

Enhancing Soil Aggregate Stability and Organic Carbon in Northwestern China through Straw, Biochar, and Nitrogen Supplementation

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