C-S-H series are synthesized at different temperatures and ages by pozzolanic reaction.The change of particle size distribution,phase composition,morphology and nanostructure of C-S-H with temperatures and ages,and th...C-S-H series are synthesized at different temperatures and ages by pozzolanic reaction.The change of particle size distribution,phase composition,morphology and nanostructure of C-S-H with temperatures and ages,and the effects of C-S-H seeds and seeds parameters on the hydration behavior and mechanical properties development of cement were investigated by DLS,XRD,SEM,^(29)Si NMR,TAM-air isothermal calorimeter and mechanical properties test.The results show that the particle size,crystallinity,basal spacing and Q^(2)/Q^(1) ratio of C-S-H increases with the increase of synthesis temperature and age.The addition of synthesized C-S-H seeds to cement pastes results in the strong acceleration effect on cement hydration and significant improvement of the early strength of cement paste and mortar.The 1 day-C-S-H seeds synthesized at room temperature can increase the strength of cement paste by about 30 MPa at 12 h.The effect does not show a very regular change with the increase of the temperature and age of seeds synthesis.Considering the effect of C-S-H seeds on the hydration and mechanical properties of cement,and economy and short cycle of seeds synthesis,the C-S-H seeds synthesized at room temperature for 1 day or 55 ℃ water bath for 12 hours is recommended..展开更多
基金Funded by National Key R&D Program of China(No.2017YFB0310001)the National Natural Science Foundation of China(Nos.51772226,51972249,51872216)。
文摘C-S-H series are synthesized at different temperatures and ages by pozzolanic reaction.The change of particle size distribution,phase composition,morphology and nanostructure of C-S-H with temperatures and ages,and the effects of C-S-H seeds and seeds parameters on the hydration behavior and mechanical properties development of cement were investigated by DLS,XRD,SEM,^(29)Si NMR,TAM-air isothermal calorimeter and mechanical properties test.The results show that the particle size,crystallinity,basal spacing and Q^(2)/Q^(1) ratio of C-S-H increases with the increase of synthesis temperature and age.The addition of synthesized C-S-H seeds to cement pastes results in the strong acceleration effect on cement hydration and significant improvement of the early strength of cement paste and mortar.The 1 day-C-S-H seeds synthesized at room temperature can increase the strength of cement paste by about 30 MPa at 12 h.The effect does not show a very regular change with the increase of the temperature and age of seeds synthesis.Considering the effect of C-S-H seeds on the hydration and mechanical properties of cement,and economy and short cycle of seeds synthesis,the C-S-H seeds synthesized at room temperature for 1 day or 55 ℃ water bath for 12 hours is recommended..
