Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
The impact of carbonation at different CO2 concentrations on the microstructure of phosphogypsum-based supersulfated cement paste
Highlights The carbonation mechanism of phosphogypsum-based supersulfated cement paste and its effect on microstructure were studied. The impact of three different CO2 concentrations (atmospheric, 5% and 20%) on the microstructure was evaluated. The CO2 concentration less than 5% is recommended due to the similar microstructure with that of natural carbonation.
Abstract This study investigates mechanisms of carbonation on the microstructure of phosphogypsum-based supersulfated cement (PSSC) paste at different CO2 concentrations (atmospheric, 5% and 20%). The products was characterized using XRD, TGA, FTIR and 27Al MAS NMR. It is observed that the main hydration products of PSSC are ettringite, C-A-S-H gels and third aluminate hydrate (TAH), and the carbonation products are calcium carbonate (mainly vaterite and calcite), secondary gypsum, and C-A-S-H gels and separate TAH with varying degrees of decalcification. The quantitative analysis of BSEM images shows that the volume change of products occurring on carbonation significantly increases porosity and pore size of the PSSC paste. Results indicate that the carbonation of PSSC at different CO2 concentrations results in a progressive carbonation degree, 5% CO2 supports the accelerated carbonation experiment in PSSC to simulate the natural carbonation process due to the same phase composition and similar microstructure with atmospheric CO2 and 20% CO2 further loosens the microstructure of PSSC for the complete decomposition of ettringite and the severe decalcification of gel products.
The impact of carbonation at different CO2 concentrations on the microstructure of phosphogypsum-based supersulfated cement paste
Highlights The carbonation mechanism of phosphogypsum-based supersulfated cement paste and its effect on microstructure were studied. The impact of three different CO2 concentrations (atmospheric, 5% and 20%) on the microstructure was evaluated. The CO2 concentration less than 5% is recommended due to the similar microstructure with that of natural carbonation.
Abstract This study investigates mechanisms of carbonation on the microstructure of phosphogypsum-based supersulfated cement (PSSC) paste at different CO2 concentrations (atmospheric, 5% and 20%). The products was characterized using XRD, TGA, FTIR and 27Al MAS NMR. It is observed that the main hydration products of PSSC are ettringite, C-A-S-H gels and third aluminate hydrate (TAH), and the carbonation products are calcium carbonate (mainly vaterite and calcite), secondary gypsum, and C-A-S-H gels and separate TAH with varying degrees of decalcification. The quantitative analysis of BSEM images shows that the volume change of products occurring on carbonation significantly increases porosity and pore size of the PSSC paste. Results indicate that the carbonation of PSSC at different CO2 concentrations results in a progressive carbonation degree, 5% CO2 supports the accelerated carbonation experiment in PSSC to simulate the natural carbonation process due to the same phase composition and similar microstructure with atmospheric CO2 and 20% CO2 further loosens the microstructure of PSSC for the complete decomposition of ettringite and the severe decalcification of gel products.
The impact of carbonation at different CO2 concentrations on the microstructure of phosphogypsum-based supersulfated cement paste
Xie, Yifan (Autor:in) / Sun, Tao (Autor:in) / Shui, Zhonghe (Autor:in) / Ding, Chao (Autor:in) / Li, Wanmin (Autor:in)
08.05.2022
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch