To obtain the compositions and microstructure of hydration products of cementitious material in different hydration ages and its growth law of filling strength, the optimal proportion of composite cementitious materia...To obtain the compositions and microstructure of hydration products of cementitious material in different hydration ages and its growth law of filling strength, the optimal proportion of composite cementitious material was determined according to the chemical composition of cement clinker which was composed of the Portland cement 32.5R, CSA 42.5 sulphoaluminate cement and two gypsum（CS）. The characterization of composite cementitious materials in different hydration ages was conducted by NMR, XRD and SEM techniques. The mechanism of hydration was explored. It is shown that the compressive strength of the test block increases gradually with the increase of hydration age. The microstructure of composite cementitious material can be changed from Al-O octahedron into Al-O tetrahedron in the hydration process. The hydrated alkali alumi niumsilicate formed with Si-O tetrahedron and Al-O tetrahedron. The degree of polymerization of Si-O tetrahedron gradually increased, and the structural strength of cementitious materials continued to increase. The diffraction peak of clinker minerals gradually decreased with the extension of hydration age. The CaSO4 completely hydrated to produce Aft during hydration which resulted in high early strength of cementitious material. The early hydration product of composite cementitious materials was Aft with a needle bar structure. The main middle and last hydration products were CSH gel and CH gel with dense prismatic shape. The microscopic pore of composite cementitious material gradually decreased and improved the later strength of filling block. The strong support was provided for mined-out area.展开更多
In order to analyze the coupled influence of temperature and humidity on early-age concrete(including cement and copper tailings),a mathematical model is introduced on the basis of the Krstulovic-Dabic hydration react...In order to analyze the coupled influence of temperature and humidity on early-age concrete(including cement and copper tailings),a mathematical model is introduced on the basis of the Krstulovic-Dabic hydration reaction kinetic equations.In such a framework,the influence of hydration-released heat and water consumption are also taken into account.The results provided by such a model are verified by means of experiments and related sensor measurements.The research results show that this model can adequately predict the internal temperature and the humidity temporal evolution laws.展开更多
基金Funded by the National Natural Science Foundation of China(No.51574055)the Natural Science Foundation of Liaoning Province(No.20170540143)
文摘To obtain the compositions and microstructure of hydration products of cementitious material in different hydration ages and its growth law of filling strength, the optimal proportion of composite cementitious material was determined according to the chemical composition of cement clinker which was composed of the Portland cement 32.5R, CSA 42.5 sulphoaluminate cement and two gypsum（CS）. The characterization of composite cementitious materials in different hydration ages was conducted by NMR, XRD and SEM techniques. The mechanism of hydration was explored. It is shown that the compressive strength of the test block increases gradually with the increase of hydration age. The microstructure of composite cementitious material can be changed from Al-O octahedron into Al-O tetrahedron in the hydration process. The hydrated alkali alumi niumsilicate formed with Si-O tetrahedron and Al-O tetrahedron. The degree of polymerization of Si-O tetrahedron gradually increased, and the structural strength of cementitious materials continued to increase. The diffraction peak of clinker minerals gradually decreased with the extension of hydration age. The CaSO4 completely hydrated to produce Aft during hydration which resulted in high early strength of cementitious material. The early hydration product of composite cementitious materials was Aft with a needle bar structure. The main middle and last hydration products were CSH gel and CH gel with dense prismatic shape. The microscopic pore of composite cementitious material gradually decreased and improved the later strength of filling block. The strong support was provided for mined-out area.
基金Provincial Quality Engineering Project of Anhui Province of China[Grant Nos.2019xfxm71 and 2020-6656].
文摘In order to analyze the coupled influence of temperature and humidity on early-age concrete(including cement and copper tailings),a mathematical model is introduced on the basis of the Krstulovic-Dabic hydration reaction kinetic equations.In such a framework,the influence of hydration-released heat and water consumption are also taken into account.The results provided by such a model are verified by means of experiments and related sensor measurements.The research results show that this model can adequately predict the internal temperature and the humidity temporal evolution laws.
