Effect Of Glass Powder On The Mechanical And Durability Of Two Mortar Systems

The tensile strength and toughness of ordinary concrete can be improved by adding glass fiber(GF).The addition of glass fiber improves the toughness of the component,but the glass fiber is easy to be corroded in the high alkaline environment,even the alkali resistant glass fiber will also face the problem of corrosion.The world consumes a huge amount of cement,but producing it consumes a lot of natural resources,emits a lot of greenhouse gases,and harms the environment.Replacing cement with glass powder and alkali-activated cementing materials not only reduces carbon dioxide emissions and energy consumption,but also recyles waste materials.In this paper,waste glass is processed into glass powder(GP),and then some of the slag in glass fiber reinforced mortar(GFRM)is replaced by cement and weak alkali.In order to improve the durability of GFRM and weak alkali composite activated slag mortar,the influence of glass powder content on GFRM and weak alkali composite activated slag mortar was studied respectively.The research results showed that:(1)The fluidity of GFRM increases with the decrease of GP particle size and with the increase of GPⅣ content with smaller particle size.When GPⅣ content of smaller particle size is 25%,slurry fluidity increases by 6.4%.When GPⅠ content is 25%,slurry fluidity decreases by 16.2%.The effects of different particle sizes of GP on GFRM strength and strength activity index were similar,which showed a trend of first increasing and then decreasing with the increase of GP dosage.The difference is that when the content of GP exceeds 5%,the enhancement effect of GPⅣ is more obvious.The dry shrinkage of GFRM decreased with the increase of GPⅣ content.GPⅣ-25 drying shrinkage decreased the most by 39.9%.Nuclear magnetic resonance analysis showed that the porosity decreased with the increase of glass powder content,and the porosity of GPⅣ-25 decreased by 46.8%.(2)GP instead of cement can reduce the corrosion of calcium hydroxide on GF.At90 and 180 days,the tensile and compressive strength of GFRM without GP was decreased,and GF was corroded or even fractured in the electron microscope scanning photos.With the increase of GP content,the tensile and compressive strength of GFRM first increased and then decreased.The flexural strength of GFRM mixed with 5% GPⅣincreased by 20.4% at 90 days of age,and the compressive strength of GFRM mixed with10%GPⅣ increased by 30.4% at 90 days of age.The addition of GP to GFRM(GP replaces part of cement)helps to improve the long-term strength of GFRM,while reducing the calcium hydroxide content and reducing the corrosion of calcium hydroxide on GF.(3)GP replacement of part of the slag increases the setting time of the slag mortar activated by the combination of calcium oxide and sodium carbonate,reduces its chloride ion erosion resistance and early strength,but increases the fluidity,reduces the drying shrinkage value,and improves the sulfate erosion resistance and fire resistance.When the content of GP is less than 20%,GP conducive to the development of the late strength.The pore structure analysis results show that with the increase of Ca O content,the porosity decreases first and then increases.The porosity increases gradually with the increase of GP content.The pore size below 50 nm has great effect on drying shrinkage.(4)GP replacement of some cement in GFRM and weak alkali compound activated slag and GP replacement of cement not only reduce carbon dioxide emissions and energy consumption,but also achieve the purpose of resource utilization.At the same time,GP can also be used to reduce the drying shrinkage of mortar,reduce the risk of mortar cracks,improve the late strength of mortar,which has a certain significance for engineering application.Figure [56] table [7] reference [117]...