The Preparation And Mechanism Study On The Early Strength, High Bonding Strength Alkaline Slag Road Repair Materials

Being patching material for cement concrete road should have the well qualityof bonding and early strength. Because of AAS (alkali-activated slag material)has many advantages, such as rich in raw material originate, the high strengthand the great dry shrinkage. So we carried on the modified experiment that AASwas applied to the patching material of the road.According to the special performance requirements of road repair concrete,we carried on the influencing disciplinarian of factors experiment from designedcomposition of the base materiai and match ratio to adjusted concrete matchratio and working performance. The results indicate that alkali-activated slagconcrete has many advantages, such as high early strength, good bondingproperties, lower rate of shrinkage and better performance under the condition ofreasonable designed concrete match ratio and correct used of adjusting settingadmixtures; adjusting setting admixtures made the initial setting time of thematerial from original 15 minutes to 70 minutes; the compression strength of 6hours of concrete could reach 24MPa, and the compression strength reached80MPa in 7 days; the bending strength of 12 hours of combining surface reached 1.4MPa, which is about twice of that Portland cement, its bending strength ofcombining surface in one day was closed to the Portland cement in 7 days, andlong face with flexural strength was not less than Portland cement; it can becontrolled under 0.03％that the 28days shrinkage rate of fine aggregate concretewith foamer and glass fiber. The wear-resisting test indicates that the earlywear-resisting performance of AAS is obviously superior to the Portland cement,its wearing quality is only 1/5 of the Portland cement in 7 days.This article is value to setting and hardening reaction of AAS in virtue ofSEM methods. Compared superficial whiteness value of AAS with compressivestrength, we found that they had stochastic model. We carried on the experimentby changing the raw materials, mix ratio, curing condition and so on. Wediscovered that the compressive strength of material can be characterized by it'ssurface color when the raw material was unchanged and air curing.Based on theSEM observation, we found they have fine binding capacity between AAS andcement paste and aggregate, and we thought this fine binding capacity was dueto the mechanical occlusion, Van der Waals force and bond common role of thematerials.