A Study On The Influence Factors Of Cement Based Materials’ TSA Under The Effect Of Electric Field

Thaumasite form of sulfate attack(TSA) is a late discovery in the types of sulfate attack which affect cement concrete durability, but it is a type that damage cement concrete’s structure seriously. In recent years, many scholars have researched a lot in TSA and achieved fruitful results. But difficulties also arose because of the slow speed of thaumasite production of cement concrete under low temperature conditions, and these difficulties affect the rapid assessment of cement-based materials to resist the thaumasite form of sulfate.Through great efforts, our group applied the electric field to accelerate TSA and we have achieved some results. These results indicate that the speed of TSA in cement concrete rises obviously by using electric field. However, there are still many problems to be solved, the most critical problem is whether the electric field changes the formation mechanism of thaumasite in cement concrete specimen when suffering sulfate attack under low temperature. In order to study this issue deeply and provide strong evidence for the application of electric field to rapid assesses TSA in cement concrete, this paper studies whether the electric field changes the formation mechanism of thaumasite in cement concrete specimen. To achieve this research objective, this paper controls the TSA formation factors(temperature, carbonates and sulfates) both in electric and full-immersion environment. The conclusions are as follows:Firstly, by controlling conditions which conclude different temperature conditions, different limestone powder content and different CO2 concentration in the air, compared to full-immersion condition, the electric field does not change the laws of thaumasite formation, and it just accelerate the speed of thaumasite formation.Secondly, in different sulfate solution, the law of thaumasite formation under electric and full-immersion environment differs. But the difference is not obvious, and it almost does not affect the electric field application in accelerating the speed of thaumasite formation.Fifth, the results of this study show that the electric field could be a method to accelerate the TSA of cement-based materials.