Effect Of Corrosion On Properties Of Modified Carbon Nanotubes Cement-based Materials

The durability of concrete in offshore construction projects is becoming more and more prominent,which makes durability an important research direction.The chloride ion in seawater is very penetrating,and it will enter the concrete through the capillary hole to reach the surface of the steel bar,which will cause the corrosion of the steel bar.The durability of concrete can be improved if chloride ions can be prevented from entering the interior of concrete or the amount of chloride ions entering the interior of structure can be controlled.On the basis of good mechanical properties,the dispersibility of modified carbon nanotubes is better than that of ordinary carbon nanotubes.It can improve the compactness of cement paste by filling the pore of cement-based material.When the concrete structure is damaged,the bridging of carbon nanotubes can play a role of micro-reinforcement and effectively restrain the formation and development of cracks.Therefore,the durability of cement-based materials can be improved by introducing a certain amount of carbon nanotubes.Modified carbon nanotubes were prepared by plasma treatment in this paper.The flexural and compressive strength of the specimens were measured after the modified carbon nanotubes were mixed into cement mortar.Contrastive analysis of the effect of modified carbon nanotubes on the properties of cement-based materials.Then the cement mortar specimens were corroded by alternating wetting and drying cycles,and the effects of the incorporation of modified carbon nanotubes on the properties of the specimens were analyzed under simulated seawater corrosion conditions.At the same time,the mechanical test was carried out,and the assistant analysis was carried out by SEM.By observing the micro-morphology of the specimens doped with modified carbon nanotubes,the mechanism of improving the properties of the specimens under seawater corrosion was analyzed.There are two reasons for the corrosion resistance of the specimens doped with modified carbon nanotubes in corrosive environment.On the one hand,the incorporation of modified carbon nanotubes improves the porosity and compactness of cement-based materials,and carbon nanotubes also form a network filling in the cement-based materials.The simultaneous action of two factors helps to reduce the entry of aqueous solutions and harmful ions into the material.On the other hand,the bridging and pulling-out effects of modified carbon nanotubes in cement-based materials consume the energy of externalloads and toughen the materials.At the same time,it also prevents the generation and development of cracks in materials,avoids water solution and harmful ions from entering into the interior of materials from cracks,and protects materials from erosion and destruction.ABAQUS software was used to simulate the compressive test of cement-based specimens from the aspect of toughening effect of modified carbon nanotubes on materials.The modified carbon nanotubes cement-based material was applied to pier column,and the seismic performance of pier column was analyzed by finite element method.Preliminary study on the effect of seawater corrosion on the properties of modified carbon nanotube cement-based composites by numerical simulation.