A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Mechanism underlying early hydration kinetics of carbonated recycled concrete fines-ordinary portland cement (CRCF-OPC) paste
https://orcid.org/0000-0001-5809-6197
https://orcid.org/0009-0001-5939-111X
Abstract Aiming to promote applications of carbonated recycled concrete fines (CRCF) as a low-carbon alternative to ordinary Portland cement (OPC), this study explored the effect of CRCF on the early hydration kinetics of OPC paste. The results show that CRCF is not only a highly active pozzolanic material but also an effective accelerator affecting the early hydration kinetics of OPC paste, thereby leading to an increased early compressive strength and a comparable 28-d compressive strength, even at a replacement ratio of 20%. Although the rheological properties and workability are negatively affected due to the high surface area and fine particle size of CRCF, the amorphous silica and silica-alumina gels and calcite present in CRCF facilitate initial ions dissolution and provide additional active nucleation sites for hydrates. As a result, the microstructure is densified due to the formation of additional C–S–H gels with high Si/Ca and Al/Ca ratios and carboaluminate phases, along with the inert filler effect of unreacted calcite particles. The incorporation of 20% CRCF to replace OPC can achieve a CO2 emissions reduction up to 25%. These indicate that the CRCF has a promising application scenario in transforming wasted concrete into high-value industrial products by CO2 activation.
Mechanism underlying early hydration kinetics of carbonated recycled concrete fines-ordinary portland cement (CRCF-OPC) paste
https://orcid.org/0000-0001-5809-6197
https://orcid.org/0009-0001-5939-111X
Abstract Aiming to promote applications of carbonated recycled concrete fines (CRCF) as a low-carbon alternative to ordinary Portland cement (OPC), this study explored the effect of CRCF on the early hydration kinetics of OPC paste. The results show that CRCF is not only a highly active pozzolanic material but also an effective accelerator affecting the early hydration kinetics of OPC paste, thereby leading to an increased early compressive strength and a comparable 28-d compressive strength, even at a replacement ratio of 20%. Although the rheological properties and workability are negatively affected due to the high surface area and fine particle size of CRCF, the amorphous silica and silica-alumina gels and calcite present in CRCF facilitate initial ions dissolution and provide additional active nucleation sites for hydrates. As a result, the microstructure is densified due to the formation of additional C–S–H gels with high Si/Ca and Al/Ca ratios and carboaluminate phases, along with the inert filler effect of unreacted calcite particles. The incorporation of 20% CRCF to replace OPC can achieve a CO2 emissions reduction up to 25%. These indicate that the CRCF has a promising application scenario in transforming wasted concrete into high-value industrial products by CO2 activation.
Mechanism underlying early hydration kinetics of carbonated recycled concrete fines-ordinary portland cement (CRCF-OPC) paste
https://orcid.org/0000-0001-5809-6197
https://orcid.org/0009-0001-5939-111X
Abstract Aiming to promote applications of carbonated recycled concrete fines (CRCF) as a low-carbon alternative to ordinary Portland cement (OPC), this study explored the effect of CRCF on the early hydration kinetics of OPC paste. The results show that CRCF is not only a highly active pozzolanic material but also an effective accelerator affecting the early hydration kinetics of OPC paste, thereby leading to an increased early compressive strength and a comparable 28-d compressive strength, even at a replacement ratio of 20%. Although the rheological properties and workability are negatively affected due to the high surface area and fine particle size of CRCF, the amorphous silica and silica-alumina gels and calcite present in CRCF facilitate initial ions dissolution and provide additional active nucleation sites for hydrates. As a result, the microstructure is densified due to the formation of additional C–S–H gels with high Si/Ca and Al/Ca ratios and carboaluminate phases, along with the inert filler effect of unreacted calcite particles. The incorporation of 20% CRCF to replace OPC can achieve a CO2 emissions reduction up to 25%. These indicate that the CRCF has a promising application scenario in transforming wasted concrete into high-value industrial products by CO2 activation.
Mechanism underlying early hydration kinetics of carbonated recycled concrete fines-ordinary portland cement (CRCF-OPC) paste
Peng, Ligang (author) / Jiang, Yi (author) / Ban, Jiaxing (author) / Shen, Yuanyuan (author) / Ma, Zihan (author) / Zhao, Yuxi (author) / Shen, Peiliang (author) / Poon, Chi-Sun (author)
2023-08-29
Article (Journal)
Electronic Resource
English
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