This paper presents investigation results on the natural ultra-fine mineral flour of crystalline silica fume (CSF) and porous quartz sand stone (PQSS) which can modify cement mortar strength under hydrothermal synthe...This paper presents investigation results on the natural ultra-fine mineral flour of crystalline silica fume (CSF) and porous quartz sand stone (PQSS) which can modify cement mortar strength under hydrothermal synthesis reaction (HSR) in the autoclave-cured condition. The replacement of cement by CSF and PQSS can signifi cantly increase the Jflerural and compressive strength which reach 22MPa and 150MPa respectively and de-crease the porosity oj the cement mortar. The ratio oj fine aggregation, standard sand to cementions material has sig nificant influence on the mortar strength. The mechanisms involved in cement and natural mineral flour and the HSR are presented. CaO/SiO2 ratio ranges from 3. 20 to 1. 11. the main hydrate phase is C2SH and there is not Tober-morite through X-Ray diffraction qualitative analysis. The new and ultra-high strength cementious material as basic material of sleeper concrete can he used in prestressed reinforcement sleeper concrete.展开更多
The increasing anthropogenic CO2 emission and global warming has challenged the China and other countries to seek new and better ways to meet the world’s increasing need for energy while reducing greenhouse gas emiss...The increasing anthropogenic CO2 emission and global warming has challenged the China and other countries to seek new and better ways to meet the world’s increasing need for energy while reducing greenhouse gas emissions.The overall proposition of this research is to develop a brand-new CO2 physical and chemical sequestration method by using solid waste of coal mining and cementitious material which are widely used for goaf backfilling in coal mining.This research developed a new testing system(constant temperature pressurized reaction chamber(CTPRC))to study the effects of different initial parameters on mineral carbonation such as different initial water-binder ratio,initial sample porosity and initial carbon dioxide pressure.The experimental results show that the CO2 consumption ratio is 15%,10%and 7%higher with relatively high initial water-binder ratio,initial sample porosity and initial CO2 pressure within 48 h.In addition,some physical and chemical evidence was found through the electron microscope scanning and XRD test to further explain the above test results.This proposed research will provide critical parameters for optimizing CO2 sequestration capacity in this cementitious backfilling material with forming agent.展开更多
An experimental program was carried out to investigate whether EVA （ethylene vinyl acetate copolymer） heat-melt adhesive can potentially act as a self-healing agent in cement-based material. The effects of incorpora...An experimental program was carried out to investigate whether EVA （ethylene vinyl acetate copolymer） heat-melt adhesive can potentially act as a self-healing agent in cement-based material. The effects of incorporation of EVA and heating on the properties of mortar were studied. Self-healing capacity of EVA specimens was also verified. The experimental results show that the addition of EVA would not greatly affect original characteristics of the matrix when EVA content was less than 5%; the interface between EVA and cement matrix was well improved after heating, which allows a significant improvement in flexural strength and toughness of specimen; pre-damaged specimens in various degrees （30%, 50% and 70%） were effectively repaired by EVA and the repair efficiency all exceeded 100%.展开更多
基金Financially Supported by the Foundation of Science of Huazhong University of Science and Technology.
文摘This paper presents investigation results on the natural ultra-fine mineral flour of crystalline silica fume (CSF) and porous quartz sand stone (PQSS) which can modify cement mortar strength under hydrothermal synthesis reaction (HSR) in the autoclave-cured condition. The replacement of cement by CSF and PQSS can signifi cantly increase the Jflerural and compressive strength which reach 22MPa and 150MPa respectively and de-crease the porosity oj the cement mortar. The ratio oj fine aggregation, standard sand to cementions material has sig nificant influence on the mortar strength. The mechanisms involved in cement and natural mineral flour and the HSR are presented. CaO/SiO2 ratio ranges from 3. 20 to 1. 11. the main hydrate phase is C2SH and there is not Tober-morite through X-Ray diffraction qualitative analysis. The new and ultra-high strength cementious material as basic material of sleeper concrete can he used in prestressed reinforcement sleeper concrete.
基金the National Natural Science Foundation of China(No.51304207)the Fundamental Research Funds for the Key Laboratory of Coal-based CO2 capture and geological storage,China University of Mining and Technology(No.2016A03).
文摘The increasing anthropogenic CO2 emission and global warming has challenged the China and other countries to seek new and better ways to meet the world’s increasing need for energy while reducing greenhouse gas emissions.The overall proposition of this research is to develop a brand-new CO2 physical and chemical sequestration method by using solid waste of coal mining and cementitious material which are widely used for goaf backfilling in coal mining.This research developed a new testing system(constant temperature pressurized reaction chamber(CTPRC))to study the effects of different initial parameters on mineral carbonation such as different initial water-binder ratio,initial sample porosity and initial carbon dioxide pressure.The experimental results show that the CO2 consumption ratio is 15%,10%and 7%higher with relatively high initial water-binder ratio,initial sample porosity and initial CO2 pressure within 48 h.In addition,some physical and chemical evidence was found through the electron microscope scanning and XRD test to further explain the above test results.This proposed research will provide critical parameters for optimizing CO2 sequestration capacity in this cementitious backfilling material with forming agent.
基金Funded by the National Basic Research Program of China (No.2009CB623203)
文摘An experimental program was carried out to investigate whether EVA （ethylene vinyl acetate copolymer） heat-melt adhesive can potentially act as a self-healing agent in cement-based material. The effects of incorporation of EVA and heating on the properties of mortar were studied. Self-healing capacity of EVA specimens was also verified. The experimental results show that the addition of EVA would not greatly affect original characteristics of the matrix when EVA content was less than 5%; the interface between EVA and cement matrix was well improved after heating, which allows a significant improvement in flexural strength and toughness of specimen; pre-damaged specimens in various degrees （30%, 50% and 70%） were effectively repaired by EVA and the repair efficiency all exceeded 100%.
