In this paper, the effect and mechanism of calcareous stone powder with size less than 0.074 mm are investigated in stone chippings concrete. The results show that the stone powder can participate in hydration reactio...In this paper, the effect and mechanism of calcareous stone powder with size less than 0.074 mm are investigated in stone chippings concrete. The results show that the stone powder can participate in hydration reaction and acts as crystal nucleus in hydration process, namely, it has hydration activity to an extent. The strength of stone chippings concrete is enhanced and the easy-mixing capacity of the concrete mortar is modified when stone chippings contain a proper amount of stone powder. The stone powder has little effect on the wearability of the concrete.展开更多
The feasibility of sulphoaluminate cement （SAC） utilization in support mortar was studied. Setting time and strength of as-received sulphoaluminate cement （SAC） paste were examined, hydration kinetics behavior was...The feasibility of sulphoaluminate cement （SAC） utilization in support mortar was studied. Setting time and strength of as-received sulphoaluminate cement （SAC） paste were examined, hydration kinetics behavior was determined through Isothermal Calorimeter, and hydration mechanism was investigated by X-Ray diffraction analysis （XRD） and field emission scanning electron microscopy analysis （FSEM）. Results showed that as-received SAC contained 61% of anhydrous calcium sulfate （3CA＇CaSO4） and dicalcium silicate （C2S）. The strength after 1 day or 3 days grew to 68.6% or 85.7% of that after 28 days respectively, while most of hydration heat was released within 1 day. The emergency of three exothermic peaks at acceleration stage was found and hydration kinetics model was established choosing the terminal time of the first exothermic peak at accelerating stage as the beginning of accelerating stage. XRD analysis suggested that large amount of ettringite （AFt） was produced at early age and FSEM observation revealed that ettringite （AFt） formed in sulphoaluminate cement （SAC） paste was characterized of different morphology which was proved to be caused by different ion concentrations.展开更多
Hydration heat evolution, non-evaporative water, setting time and SEM tests were peorormed to investigate the effect of fine steel slag powder on the hydration process of Portland cement and its mechanism. The results...Hydration heat evolution, non-evaporative water, setting time and SEM tests were peorormed to investigate the effect of fine steel slag powder on the hydration process of Portland cement and its mechanism. The results show that the effect of fine steel slag powder on the hydration process of Portland cement is closely related to its chemical composition, mineral phases, fineness, etc. Fine steel slag powder retards the hydration of portland cement at early age. The major reason for this phenomenon is the relative high content of MgO , MnO2, P2O5 in steel slag, and MgO solid solved in C3 S contained in steel slag.展开更多
文摘In this paper, the effect and mechanism of calcareous stone powder with size less than 0.074 mm are investigated in stone chippings concrete. The results show that the stone powder can participate in hydration reaction and acts as crystal nucleus in hydration process, namely, it has hydration activity to an extent. The strength of stone chippings concrete is enhanced and the easy-mixing capacity of the concrete mortar is modified when stone chippings contain a proper amount of stone powder. The stone powder has little effect on the wearability of the concrete.
基金Funded by the National Natural Science Foundation of China(Nos.51379163 and 51109170)the National Key Research Program(973 Program)(No.2013CB035901)
文摘The feasibility of sulphoaluminate cement （SAC） utilization in support mortar was studied. Setting time and strength of as-received sulphoaluminate cement （SAC） paste were examined, hydration kinetics behavior was determined through Isothermal Calorimeter, and hydration mechanism was investigated by X-Ray diffraction analysis （XRD） and field emission scanning electron microscopy analysis （FSEM）. Results showed that as-received SAC contained 61% of anhydrous calcium sulfate （3CA＇CaSO4） and dicalcium silicate （C2S）. The strength after 1 day or 3 days grew to 68.6% or 85.7% of that after 28 days respectively, while most of hydration heat was released within 1 day. The emergency of three exothermic peaks at acceleration stage was found and hydration kinetics model was established choosing the terminal time of the first exothermic peak at accelerating stage as the beginning of accelerating stage. XRD analysis suggested that large amount of ettringite （AFt） was produced at early age and FSEM observation revealed that ettringite （AFt） formed in sulphoaluminate cement （SAC） paste was characterized of different morphology which was proved to be caused by different ion concentrations.
基金Funded by National 973 Project (No.2001CB610704-2)
文摘Hydration heat evolution, non-evaporative water, setting time and SEM tests were peorormed to investigate the effect of fine steel slag powder on the hydration process of Portland cement and its mechanism. The results show that the effect of fine steel slag powder on the hydration process of Portland cement is closely related to its chemical composition, mineral phases, fineness, etc. Fine steel slag powder retards the hydration of portland cement at early age. The major reason for this phenomenon is the relative high content of MgO , MnO2, P2O5 in steel slag, and MgO solid solved in C3 S contained in steel slag.
