The introduction of recycled-aggregate concrete specifications in Japan and the research into the freezing–thawing resistance of recycled-aggregate concrete

Koga, H.; Katahira, Hiroshi; Shimata, Akinori

doi:10.1007/s10163-022-01412-x

Cited by 12 publications

(6 citation statements)

References 6 publications

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“…In contrast to prior studies that indicated a decrease in freeze-thaw resistance with an increase in the recycled aggregate mixing ratio, our findings revealed an increase in freeze-thaw resistance as the proportion of recycled coarse aggregate increased [43,44]. This divergence in results can be attributed to the presence of entrained cells within the mortar adhered to the recycled aggregate, which reduces the cell spacing coefficient in concrete.…”

Section: Freeze-thaw Resistancecontrasting

confidence: 99%

Effects of the recycled coarse aggregate mixing ratio on the characteristics of concrete with different design strengths

Yoon,

Choi,

Jeon

2024

J Mater Cycles Waste Manag

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In this study, the characteristics of recycled aggregate concrete according to the mixing ratio of recycled coarse aggregate(RCA) were analyzed for different design strengths to explore the use of recycled materials in the production of ready-mixed concrete. The results show that, depending on the ratio of recycled aggregate, the compressive strength is similar to that of normal concrete and does not deteriorate. Therefore, it is possible to achieve a target design strength. Furthermore, if the ratio of recycled coarse aggregate for concrete is up to 25% of the total aggregate amount (50% of the total coarse aggregate), slump does not cause problems. Our findings show that the higher the design standard strength, the greater the amount of powder, and the more stringent the management of slump reduction, unit quantity, and performance necessary. The obtained results show that recycled aggregate can be used to produce ready-mixed concrete after adjusting its mixing ratio and concrete mix proportions.

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Section: Freeze-thaw Resistancecontrasting

confidence: 99%

Effects of the recycled coarse aggregate mixing ratio on the characteristics of concrete with different design strengths

Yoon,

Choi,

Jeon

2024

J Mater Cycles Waste Manag

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“…Studentized residuals are the values obtained by dividing the residuals by the standard deviation, which are used to visually determine whether the residuals follow a normal distribution [17][18][19]. The studentized residuals can be derived from the ordinary residuals, which plays a very important role in the diagnosis of regression model [20,21]. The ANOVA function of Design-expert software can be used to derive the studentized residuals of compressive strength, split tensile strength and slump regression models, and the results are shown in figure 2.…”

Section: The Residual Of the Modelsmentioning

confidence: 99%

Mixture ratio optimization of basalt fiber recycled aggregate concrete based on RSM

Li,

Sun

2024

Mater. Res. Express

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In this paper, the effects of W/B ratio, recycled aggregate (RA) content and basalt fiber (BF) dosage on the compressive strength, splitting tensile strength and slump of concrete were investigated and a regression model was developed for analysis and prediction, and the regression model was validated using ANOVA and confidence analysis. Statistical analysis revealed that W/B ratio, RA content and BF dosage had significant effects on all properties of concrete. The established regression model fits the experimental data well and can accurately predict the properties of concrete. It was also found that there was a significant interaction between W/B ratio and BF dosage, as well as RA content and BF dosage, which suggests that the combination of these factors should be considered in the design of concrete mix to achieve optimum performance. The predicted values of compressive strength, split tensile strength and slump of concrete under optimum proportioning were in good agreement with the experimental values. Therefore, optimizing the concrete proportion by response surface methodology can improve the testing efficiency and obtain basalt fiber recycled aggregate concrete that meets the design requirements and has better overall performance.

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“…Several countries have already included the use of recycled aggregates in their regulations. Most of them establish a quality classification of recycled aggregates according to their composition or parameters, such as absorption and density, and then define the limits of the permissible contents and the purposes for which they can be used (strength level, structural use, type of exposure) [9,11,140]. The regulations generally allow the use of RA in nonstructural or structural concretes exposed to conditions of low aggressiveness to their durability.…”

Section: Regulationsmentioning

confidence: 99%

Current Knowledge and Pending Research on Sulfate Resistance of Recycled Aggregate Concrete

Santillán,

Zega,

Irassar

2024

Sustainability

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The building sector’s sustainability requires construction and demolition waste (CDW) to contribute to the circular economy. Among the CDW, recycled concrete aggregates (RA) have been mainly studied to replace natural aggregates. Still, the approval of their use in regulations and standards is slower. Some barriers to the adoption of RA are related to the durability of recycled aggregate concrete (RAC). However, their physical and mechanical properties have been extensively studied. The durability risks associated with sulfate attacks have been solved for conventional concrete. However, sulfate attack on recycled concrete still raises numerous unsolved questions. In this literature review, the experience of sulfate attack on RAC is compiled and analyzed using a compressive framework highlighting the most relevant aspects of the new matrix in RAC and the old matrix of RA to support its relevance to the damaging sulfate process. Suggestions for further research are presented to understand the full extent of this issue and contribute to incorporating and extending recycled aggregates into existing regulations.

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The introduction of recycled-aggregate concrete specifications in Japan and the research into the freezing–thawing resistance of recycled-aggregate concrete

Cited by 12 publications

References 6 publications

Effects of the recycled coarse aggregate mixing ratio on the characteristics of concrete with different design strengths

Effects of the recycled coarse aggregate mixing ratio on the characteristics of concrete with different design strengths

Mixture ratio optimization of basalt fiber recycled aggregate concrete based on RSM

Current Knowledge and Pending Research on Sulfate Resistance of Recycled Aggregate Concrete

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