Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
NMR study on bleeding properties of the fresh cement pastes mixed with polycarboxylate (PCE) superplasticizers
https://orcid.org/0000-0002-8300-4343
Graphical abstract Display Omitted
Highlights NMR can measure the microstructure, bleeding extent and PCEs concentration. PCEs synthesized with high acid to ether ratio can reduce bleeding. PCEs molecules in bleeding water were diluted during bleeding process. More bleeding water results in larger microstructure change of fresh cement paste.
Abstract This study investigated the bleeding properties of fresh cement paste mixed with various polycarboxylate superplasticizers (PCEs) using low-field nuclear magnetic resonance (NMR). The PCE superplasticizers were synthesized with various acid to ether ratio, molecule weight of methyl allyl alcohol polyoxyethylene ether (HPEG) and functional groups. The bleeding process of fresh cement paste mixed with the PCE superplasticizers was monitored by low-field NMR and the bleeding rate was obtained with the calculation of transverse relaxation time (T 2) peaks. Results showed that the proposed NMR method can not only evaluate the bleeding extent, probe the microstructure of fresh cement paste but also provide information about the PCEs concentration of bleeding water. It was found that PCE superplasticizers synthesized with high acid to ether ratio would reduce the bleeding, and PCE superplasticizers synthesized with the HPEG of molecule weight 4400 and functional group of methyl methacrylate (MMA) would lead to less bleeding when the fresh cement paste reached the same fluidity. The T 2 relaxation time of bleeding water increased with bleeding rate, which implies the PCEs molecules in bleeding water was diluted during the bleeding process. Furthermore, the results suggest more bleeding water coming out from the pore water results in larger microstructure changes due to sedimentation.
NMR study on bleeding properties of the fresh cement pastes mixed with polycarboxylate (PCE) superplasticizers
https://orcid.org/0000-0002-8300-4343
Graphical abstract Display Omitted
Highlights NMR can measure the microstructure, bleeding extent and PCEs concentration. PCEs synthesized with high acid to ether ratio can reduce bleeding. PCEs molecules in bleeding water were diluted during bleeding process. More bleeding water results in larger microstructure change of fresh cement paste.
Abstract This study investigated the bleeding properties of fresh cement paste mixed with various polycarboxylate superplasticizers (PCEs) using low-field nuclear magnetic resonance (NMR). The PCE superplasticizers were synthesized with various acid to ether ratio, molecule weight of methyl allyl alcohol polyoxyethylene ether (HPEG) and functional groups. The bleeding process of fresh cement paste mixed with the PCE superplasticizers was monitored by low-field NMR and the bleeding rate was obtained with the calculation of transverse relaxation time (T 2) peaks. Results showed that the proposed NMR method can not only evaluate the bleeding extent, probe the microstructure of fresh cement paste but also provide information about the PCEs concentration of bleeding water. It was found that PCE superplasticizers synthesized with high acid to ether ratio would reduce the bleeding, and PCE superplasticizers synthesized with the HPEG of molecule weight 4400 and functional group of methyl methacrylate (MMA) would lead to less bleeding when the fresh cement paste reached the same fluidity. The T 2 relaxation time of bleeding water increased with bleeding rate, which implies the PCEs molecules in bleeding water was diluted during the bleeding process. Furthermore, the results suggest more bleeding water coming out from the pore water results in larger microstructure changes due to sedimentation.
NMR study on bleeding properties of the fresh cement pastes mixed with polycarboxylate (PCE) superplasticizers
https://orcid.org/0000-0002-8300-4343
Graphical abstract Display Omitted
Highlights NMR can measure the microstructure, bleeding extent and PCEs concentration. PCEs synthesized with high acid to ether ratio can reduce bleeding. PCEs molecules in bleeding water were diluted during bleeding process. More bleeding water results in larger microstructure change of fresh cement paste.
Abstract This study investigated the bleeding properties of fresh cement paste mixed with various polycarboxylate superplasticizers (PCEs) using low-field nuclear magnetic resonance (NMR). The PCE superplasticizers were synthesized with various acid to ether ratio, molecule weight of methyl allyl alcohol polyoxyethylene ether (HPEG) and functional groups. The bleeding process of fresh cement paste mixed with the PCE superplasticizers was monitored by low-field NMR and the bleeding rate was obtained with the calculation of transverse relaxation time (T 2) peaks. Results showed that the proposed NMR method can not only evaluate the bleeding extent, probe the microstructure of fresh cement paste but also provide information about the PCEs concentration of bleeding water. It was found that PCE superplasticizers synthesized with high acid to ether ratio would reduce the bleeding, and PCE superplasticizers synthesized with the HPEG of molecule weight 4400 and functional group of methyl methacrylate (MMA) would lead to less bleeding when the fresh cement paste reached the same fluidity. The T 2 relaxation time of bleeding water increased with bleeding rate, which implies the PCEs molecules in bleeding water was diluted during the bleeding process. Furthermore, the results suggest more bleeding water coming out from the pore water results in larger microstructure changes due to sedimentation.
NMR study on bleeding properties of the fresh cement pastes mixed with polycarboxylate (PCE) superplasticizers
Ji, Yanliang (Autor:in) / Sun, Zhenping (Autor:in) / Yang, Jingbing (Autor:in) / Pel, Leo (Autor:in) / jarmouzi Raja, Al. (Autor:in) / Ge, Haosheng (Autor:in)
21.12.2019
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Cement , Low-field NMR , Bleeding , PCEs
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