Study On Preparation And Properties Of Geopolymer-based Pavement Repair Mortar

With the increasing traffic volume and vehicle load,cement concrete pavement has been damaged to varying degrees.If it is not repaired in time,it will cause greater economic losses.Geopolymer is a new type of cementitious material.Because of its high early strength,good interfacial bonding strength,rapid strength development,good durability,energy saving and environmental protection,geopolymer is generally considered as a new type of cementitious material which can replace Portland cement.Therefore,it can be used as a new type of patching material for rapid repair of concrete pavement.The main purpose of this paper is to develop economic,green and environmental protection cement concrete pavement repair materials.Geopolymer-based repairing mortar was prepared with slag,fly ash,sodium silicate and NaOH as main raw materials.The properties of repairing materials were modified by fibers and organic polymers to meet the requirements of mechanical properties,workability,shrinkage and cohesion of pavement repairing materials.The microstructure of the mortar was analyzed by SEM and XRD.The results show that:The results show that the geopolymer-based repairing mortar has excellent flexural and compressive strength,fluidity and setting time.Its early strength is high and hardening speed is fast,which meets the requirements of rapid open traffic after repairing.By exploring the influence of different factors on the performance of geopolymer-based repairing mortar,the optimum mix ratio was obtained.The effect of basalt fibers and polypropylene fibers on the properties of geopolymer-based repairing mortar was studied.The results show that the mechanical strength and shrinkage of repairing mortar can be effectively improved by adding proper amount of fibers.When the basalt fibers content is 0.6%,the shrinkage rate of repairing mortar is less than 9%in 28 days;when the polypropylene fibers content is 0.6%,the flexural compressive strength and working performance of repairing mortar are excellent.It meets the requirements of JC/T 2381-2016 specification for repairing mortar.The influence of emulsified asphalt and epoxy resin emulsion on the properties of geopolymer based repair mortar is studied.The results show that emulsified asphalt and epoxy emulsion have better effect on repairing mortar's working performance and caking property,and the mechanical strength has little loss,but it meets the basic requirements of resisting fracture and compression strength in construction specifications.When the content of emulsified asphalt is 2%,the flexural and compressive strength of repaired mortar is the best for 6h and 1d,and the bond tensile strength of repaired mortar is obviously improved.When the content of epoxy resin emulsion is 3.5%,the compressive strength and compressive strength of the repaired mortar 6h and 1D are the highest.It has obvious modification effect on geopolymer-based repairing mortar.