Effect Of Triethanolamine On Binding Chloride Ion Properties Of Cement-based Materials

In marine environment,the structural damage of concrete often occurs due to reinforcement corrosion,resulting in the reduction of service life.The main cause of reinforcement corrosion is chloride corrosion.At present,the chloride corrosion resistance of concrete is mainly improved by improving the chloride ion binding capacity of cement-based materials or reducing the penetration rate of external chloride ions into concrete.In this paper,the effect of triethanolamine(TEA)on the binding properties of chloride ions in cement-based materials was studied.The effects of TEA on the binding properties of chloride ions in cement metakaolin,cement slag and cement fly ash systems were studied.The influence of TEA on the ion dissolution of metakaolin,slag and fly ash was studied,and the relationship between the ion dissolution law and the properties of binding chloride ions was established.Through microscopic test and analysis,the influence mechanism of TEA on the curing chloride ion properties of cement-based materials is revealed.The main research results are as follows:(1)With the increase of TEA content,the chloride ion binding capacity of cement metakaolin,cement slag and cement fly ash systems first increased and then decreased.When the content of TEA was 0.03%,0.05% and 0.03%,the binding chloride ion content of the three cement-based systems reached the maximum,and the corresponding 28 day compressive strength increased by 23%,31% and 36%respectively.TEA has the same effect on the binding chloride ion properties and mechanical properties of cement-based materials.(2)Tea increased the dissolution of aluminum ions,iron ions and silicon ions in metakaolin,slag and fly ash.The ion dissolution increased with the increase of TEA content.The greater the total amount of aluminum ions,iron ions and silicon ions dissolved,the stronger the ability of cement-based materials to bind chloride ions.After 28 days of hydration,the total amount of ions dissolved in the three cement-based systems increased by 88.3%,41.8% and 208.9% respectively,and the corresponding chloride ion curing amount increased by 32.7%,40.1% and 34.2%respectively.(3)TEA improves the ability of chemical binding and physical adsorption of chloride ions of cement-based materials.Aluminum and iron ions in pore solution participate in chemical reaction to form AFm,and AFm reacts with chloride ions to form Friedel salt.TEA improves the concentration of aluminum and iron ions in pore solution and promotes the formation of Friedel salt in cement-based materials.The silicon ions in the pore solution participate in chemical reaction to form C-S-H gel.The gel adsorbed chloride ions through the double layer.TEA enhanced the concentration of silicon ions in the pore solution,and promoted the formation of C-S-H gel in cement-based materials.