Invention Of Ionically Conductive Mortar And Reseach On Its Performance

Traditional electrically conductive concrete (TECC), a composite material made by adding conductive materials to the traditional cement-based mixture. The most commonly used conductive materials in TECC include steel fiber, steel slag, carbon fiber and nano carbon black. There are many drawbacks in TECC. For example, steel fiber or steel slag are easily rusty, the carbon fibers tend to twine around each other, etc. Unlike TECC, the"ionically conductive mortar (ICM)” takes advantage of directional migration of ions in the free moisture of the composite, it means ICM has some advantage of the TECC, such as the simple manufacturing process, the dispersion and degradation of the conductive materials,and so on. As the conductive mechanism of ICM is totally different from TECC,a series of specimens of ICM were made with different type and concentration of electrolyte solution(CuSO4 and FeSO4) and different electrode materials, and their electrical conductivities were measured. Further, the factor influencing the conductivity of ICM was discussed. The mix proportion, manufacturing process and configuration Was optimized according to macroscopic and microscopic test results.The primary factors which influence the conductivity of ICM include concentration and species of ionie solution, porosity, electrode types, and so on. Further, porosity of ICM is influenced by the additive category, mix proportion and age, etc. The larger porosity can effectively improve the penetration efficiency. In this paper, in order to improve the porosity of samples, aluninite powder is added. Meanwhile, the penetration test and microscopic test are carried out using specimens that have different curing time and different water cement ratio. The test indicated that a small amount of porosity will be occupied by hydration products with the increase of age, such as ettringite, etc. When water-cement ratio is larger,mortar has good liquidity, and capillary connected hole owning the uniform aperture size is formed. Therefore, the optimal scheme of making ICM's specimen is curing 28 days, and the water cement ratio is 0.7.The other primary factors which influence the conductivity of ICM are concentration and species of ionic solution. This paper chose the CuSO4 solution and FeSO4 solution as conductive materials to make ICM, the test indicated that electrolyte concentration corresponds to an optimal concentration range, different electrolyte has different solubility,and has different optimal concentration range. Concentration of optimization experiment show that CuSO4 solution's optimal mass fraction is 2.91%?3.85% and FeSO4 is 9.91%?10.71% when the specimen's w/c equals 0.5. It can improve penetration efficiency when making ICM and enhance conductivity in the range. This article also chose galvanized iron mesh and copper wire mesh as the electrode to make ICM, the test indicated that different electrode has different exchange current density, the larger exchange current density can effectively alleviate the polarization effect, and the electrode that directly react with the electrolyte solution should not be chosen.The age(curing time and working time) also affect the conductivity of ICM, with the increase of age, specimen's internal moisture will be consumed and evaporated, which make the electrolyte concentration to be changed, separate out and the pore to be blocked. It can influence specimen's conductivity finally. The epoxy resin,that can prevent evaporation of water effectively, plays an important role in ensuring persistent and good electrical conductivity of ICM. Test result showed that specimens' electrical resistivity of roller coating epoxy resins will be far less than the one not epoxy-coated. In order to further guarantee the stability of ICM's conductivity, the new construction measure is carried out to add electrolyte solution automatically. Test result showed that this measure can effectively guarantee the conductivity of ICM.