Study On The Influence Of Glass Powder On The Microcosmic And Mechanical Properties Of Concrete

With the extensive use of glass products,the world produces a large number of glass solid waste every year.Waste glass powder is used as auxiliary cementitious material to replace cement in concrete.This will effectively solve the problem of waste glass landfill treatment,but also can improve the performance of concrete to a certain extent.In this paper,the effects of different replacement rates of glass powder(GP)on the mechanical properties of glass powder concrete were studied.The influence of waste glass powder on hydration of composite cement slurry was studied by means of measurement of hydration heat,X-ray diffraction,thermogravimetry and scanning electron microscope.The influence of waste glass powder on the pore structure of glass concrete was studied by mercury injection instrument.The following conclusions are drawn:(1)The macroscopic mechanical properties of glass powder concrete are close to those of ordinary concrete,and even better than that of ordinary concrete.Although the mechanical properties of glass concrete in the early stage are lower than that of ordinary concrete,the mechanical properties of glass concrete are gradually close to those of ordinary concrete due to the volcanic ash reaction of glass powder as the age increases.(2)By curing the glass concrete for one year,the compressive strength of the glass concrete with different GP replacement rate is close to that of the pure cement.Through the calculation of the activity index,it can be found that the activity index increases with the increase of glass powder,indicating that the pozzolane reaction of GP is the main source of the increase of the strength of glass powder concrete in the later period.(3)The hydration process of cement composite slurry is similar to that of pure cement slurry.With the increase of hydration degree,the overall structure compactness of the cement composite slurry containing glass powder increases at 28d.From the perspective of the overall structure of cement composite slurry,the hydration products are relatively evenly distributed,and there are not a large number of layered CH similar to that of pure cement.And as the replacement rate of glass powder increases,this effect becomes more and more obvious.After reaching 90d,the overall structure of cement composite slurry becomes more and more compact,and the hydration products are indistinguishable.Compared with pure cement slurry,there is hardly regional CH crystal aggregation in cement composite slurry with different glass powder contents.Moreover,the c-s-h gel with low calcium-silicon ratio produced by the glass powder can bind with a certain amount of Na~+.(4)In the early days,the partial replacement of glass powder for cement will increase the porosity of glass powder concrete to some extent.After 120d,the porosity of glass powder concrete is close to that of ordinary concrete,which is consistent with the macroscopic mechanical properties of chapter 3.(5)The addition of glass powder is beneficial to the formation of cementing holes in the later stage of glass powder concrete.Moreover,the glass powder has little effect on the quantity of macropores and capillary pores of concrete,and can reduce the number of transition pores to a certain extent.