Study On Strength Characteristics And Durability Of Waste Glass Powder Cement Mortar

The supply of natural resources of standard sand is decreasing greatly.Therefore,glass powder with specific dosage and particle size is used to replace the standard sand to make glass cement mortar and concrete.Using waste glass in construction industry can save cost,create higher economic benefits,turn waste into treasure and recycle limited resources.Because the glass powder with finer particle size has certain pozzolanic activity and microaggregate filling effect,it can improve the strength,sulfate attack resistance and drying shrinkage resistance of the waste glass powder cement mortar.Therefore,glass powder with larger particle size parameters is selected to replace standard sand in this paper to study the performance of glass powder cement mortar.The main research contents and relevant conclusions are as follows:(1)In order to study the strength characteristics and mechanism of waste glass powder cement mortar,20-100 mesh,100-200 mesh and 200-500 mesh glass powder were used to replace 10%,15% and 20% standard sand in the same volume to make cement sand test blocks,and the bending strength and compressive strength at 3d,7d,14 d and 28 d were measured.Scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)were used to analyze the microstructure of waste glass powder cement mortar.The results show that: The compressive strength and flexural strength of waste glass powder cement mortar first increase and then decrease with the increase of glass powder content.With the increasing of curing age,the compressive strength and flexural strength of cement mortar are significantly improved.The smaller the glass powder particle size is,the higher the 28 d compressive strength and flexural strength of cement mortar are.But the strength development law of waste glass powder cement mortar with different particle size is different.From SEM and EDS image analysis,it can be seen that compared with ordinary cement mortar,the internal hydration products of glass powder cement mortar are more,and the compactness is improved.When the glass powder content is 15%,with the decrease of the glass powder particle size,the cement mortar compactness gradually increases,and the internal hydration products are more.When the glass powder particle size is 200-500 mesh,with the increase of glass powder content,the cement mortar compactness first increases and then decreases,and the internal hydration products first increase and then decrease.This is mainly attributed to the microaggregate filling effect,pozzolanic effect and the change of interfacial transition zone.(2)Four groups were selected from the mechanical properties to explore the effects of curing age,glass powder content and particle size on the sulfate resistance of cement mortar.The results show that with the increase of curing age,the mass loss rate of glass cement mortar is stable at 1,and the decline rate of the mass loss rate and the ratio coefficient of flexural and compressive resistance decreases obviously,which indicates that the glass cement mortar has remarkable resistance to sulfate attack.With the decrease of glass powder content and particle size,the resistance to sulfate attack is improved.This is closely related to pozzolanic reaction of glass powder and microaggregate filling effect.(3)Four groups were selected from the mechanical properties to explore the effects of curing age,glass powder content and particle size on the drying shrinkage properties of cement mortar.The research shows that with the increase of curing age,the drying shrinkage rate of glass powder cement mortar increases rapidly in the early stage and slowly in the later stage,and the drying shrinkage rate is obviously lower than that of the reference group.With the increase of glass powder content and the decrease of particle size,the drying shrinkage performance is improved to some extent,and the influence of glass powder content is greater than that of glass powder particle size.This is mainly due to the pozzolanic activity of glass powder itself and the effect of microaggregate filling.