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Performance Improvement of Recycled Coarse Aggregate Concrete Using a Shrinkage-Reducing Agent
https://orcid.org/http://orcid.org/0000-0002-2299-2149
https://orcid.org/http://orcid.org/0000-0003-0165-237X
Generally, the drying shrinkage of recycled aggregate concrete is affected by the amount and quality of adhering paste and is more significant than that of raw aggregate concrete. Therefore, the Japanese building code restricts the use of structural members based on the quality of recycled aggregate, and only high-quality recycled aggregate are approved for structural members.
In this study, we investigated a method to improve the performance of concrete using low- and medium-recycled coarse aggregates. We attempted to reduce the drying shrinkage by diluting a shrinkage-reducing agent (SR) and spraying it on the recycled coarse aggregates. Because an SR can reduce the freeze–thaw resistance owing to its effect on the amount of air entrained, we also investigated the effect of spraying a diluted SR on the freeze–thaw resistance of the aggregates. The amount of SR that impregnated the aggregate surface was significantly reduced compared to when a shrinkage reducer is added as an admixture to concrete.
Results showed that the SR reduced the strain. However, the degree of reduction depended on the combined quality of the binder and recycled aggregate and was often insignificant. This tendency is due to the variation in the quality of the recycled aggregate. The amount of SR that impregnated an aggregate affected its drying shrinkage. In addition, the rate of reduction of relative dynamic modulus of elasticity with freeze–thaw cycles decreased when the SR was sprayed, and the freeze–thaw resistance improved.
Performance Improvement of Recycled Coarse Aggregate Concrete Using a Shrinkage-Reducing Agent
https://orcid.org/http://orcid.org/0000-0002-2299-2149
https://orcid.org/http://orcid.org/0000-0003-0165-237X
Generally, the drying shrinkage of recycled aggregate concrete is affected by the amount and quality of adhering paste and is more significant than that of raw aggregate concrete. Therefore, the Japanese building code restricts the use of structural members based on the quality of recycled aggregate, and only high-quality recycled aggregate are approved for structural members.
In this study, we investigated a method to improve the performance of concrete using low- and medium-recycled coarse aggregates. We attempted to reduce the drying shrinkage by diluting a shrinkage-reducing agent (SR) and spraying it on the recycled coarse aggregates. Because an SR can reduce the freeze–thaw resistance owing to its effect on the amount of air entrained, we also investigated the effect of spraying a diluted SR on the freeze–thaw resistance of the aggregates. The amount of SR that impregnated the aggregate surface was significantly reduced compared to when a shrinkage reducer is added as an admixture to concrete.
Results showed that the SR reduced the strain. However, the degree of reduction depended on the combined quality of the binder and recycled aggregate and was often insignificant. This tendency is due to the variation in the quality of the recycled aggregate. The amount of SR that impregnated an aggregate affected its drying shrinkage. In addition, the rate of reduction of relative dynamic modulus of elasticity with freeze–thaw cycles decreased when the SR was sprayed, and the freeze–thaw resistance improved.
Performance Improvement of Recycled Coarse Aggregate Concrete Using a Shrinkage-Reducing Agent
https://orcid.org/http://orcid.org/0000-0002-2299-2149
https://orcid.org/http://orcid.org/0000-0003-0165-237X
Generally, the drying shrinkage of recycled aggregate concrete is affected by the amount and quality of adhering paste and is more significant than that of raw aggregate concrete. Therefore, the Japanese building code restricts the use of structural members based on the quality of recycled aggregate, and only high-quality recycled aggregate are approved for structural members.
In this study, we investigated a method to improve the performance of concrete using low- and medium-recycled coarse aggregates. We attempted to reduce the drying shrinkage by diluting a shrinkage-reducing agent (SR) and spraying it on the recycled coarse aggregates. Because an SR can reduce the freeze–thaw resistance owing to its effect on the amount of air entrained, we also investigated the effect of spraying a diluted SR on the freeze–thaw resistance of the aggregates. The amount of SR that impregnated the aggregate surface was significantly reduced compared to when a shrinkage reducer is added as an admixture to concrete.
Results showed that the SR reduced the strain. However, the degree of reduction depended on the combined quality of the binder and recycled aggregate and was often insignificant. This tendency is due to the variation in the quality of the recycled aggregate. The amount of SR that impregnated an aggregate affected its drying shrinkage. In addition, the rate of reduction of relative dynamic modulus of elasticity with freeze–thaw cycles decreased when the SR was sprayed, and the freeze–thaw resistance improved.
Performance Improvement of Recycled Coarse Aggregate Concrete Using a Shrinkage-Reducing Agent
Lecture Notes in Civil Engineering
Ilki, Alper (editor) / Çavunt, Derya (editor) / Çavunt, Yavuz Selim (editor) / Sato, Sachie (author) / Tanano, Hiroyuki (author)
International Symposium of the International Federation for Structural Concrete ; 2023 ; Istanbul, Türkiye
2023-06-01
9 pages
Article/Chapter (Book)
Electronic Resource
English
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