Preparation Of Submicron Glass Powder And Study On Its Hydration Properties

The development of waste resource and sustainable environment have attracted much attention.At present,the application of waste glass in concrete has become one of the hotspots.Cement is replaced by glass powder,which is used as a cementitious material.It is surprised that the problem of the waste glass was effectively solved.On the one hand,the amount of cement is reduced,the exploitation of natural resources is also reduced.Meanwhile,the emission of harmful gases in the production of cement is reduced,and then environment is greatly improved.The preparation process of submicron glass powder?0.1¹um?is realized in this paper.In addition,a part of cement is replaced by same mass of submicron glass powder,and the composite cementitious materials are prepared.The micro-experiment is studied by scanning electron microscopy?SEM?and X ray diffraction?XRD?.The hydration property and activity of submicron glass powder are studied by changing the conditions of contents,water cement ratio,temperatures,ages and so on.The following conclusions are obtained.?1?The median particle size(D₅₀)of submicron glass powder is 664nm,and distribution of the particle size is also concentrated.More than 90%of the particles keep in the range of submicron?0.1¹um?.More than 70%of chemical composition of submicron glass powder is SiO₂,which has potential pozzolanic property.?2?The standard consistency of submicron glass powder is slightly higher than that of cement.But the standard consistency of submicron glass powder slightly changes with increasing the contents of waste glass.Meanwhile,the curing time of complex binder delays with increasing the contents of waste glass.In addition,the initial curing and final curing time of complex binder with submicron glass powder are long than that of ordinary glass powder in the same condition.?3?The fluidity of composite paste gradually increases with increasing content of submicron glass powder.?4?The exothermic rate in the induction stage and the accelerated stage is obviously reduced after the addition of submicron glass powder.But the second exothermic peak was delayed.Moreover,with the increase of submicron glass powder content,the exothermic rate increases with increasing content of submicron glass powder.?5?A part of cement is replaced by same mass of submicron glass powder,and the composite cementitious materials are prepared.The activity of glass powder is very strong when the content of glass powder is no more than 20%at the early hydration stage,and the glass powder has little effect on the strength of samples.When content of the glass powder is up to30%,the activity of samples decreases obviously,and the strength of samples are also reduced greatly.When the hydration age is over 28d,the activity of glass powder is over 80%,and the strength of samples with large volume of glass powder is greatly improved.The strength gap between the samples and the pure cement paste is gradually shortened.?6?It can be concluded that the strength of sample increases with decreasing the water cement ratio in the condition of same ages.When the water cement ratio is very large,the early strength is low,and the later strength obviously increases.On the contrary,the early strength of sample in the condition of low water cement ratio is higher than that of other sample,but its later strength is slowly improve.?7?Submicron glass powder shows high activity in the condition of high temperature.Submicron glass powder can weaken some negative effects,and improve the strength of samples.The strength of sample slowly decreases with increasing contents of submicron glass powder.However,the positive effect of submicron glass powder decreases with increasing curing age.?8?After adding submicron glass powder,the content of Ca?OH?₂ in the composite slurry decreases with the occurrence of pozzolanic reaction,which can increase the resistance of sulfate and other substances to test block corrosion.In this paper,the activity of submicron glass powder and its hydration properties are studied.It provides theoretical and technical basis for the utilization of waste glass powder.