Effects Of Triisopropanolamine On Hydration And Properties Of Cement

In recent years, with the reapid development of national economy, the cement annual output is increasing rapidly. As a high energy consumption industry, its energy saving and emission reduction is really a tough task. During the grinding of cement, the addition of cement grinding aids can effectively enhance grinding efficiency, reduce energy consumption and production cost. The research of cement grinding aid is of great significance to environmental protection and social economy development. Triisopropanolamine (TIPA) is one of commonly used components of cement grinding aids. At present, there have been researchs focused on the influence of TIPA on strength and hydration of portland cement and portland cement containing fine limestone grains. While the researchs on its influence on the hydration mechnasim of limestone portland cement is still not comprehensive enough. The microstructure of harden cement paste. Therefor, this thesis is focused on the influence of TIPA on strength, hydration and microstructure of harden portland cement and limestone portland cement.Results showed that TIPA could not notably enhance the strength of cement at early ages, but with the increase of hydration time, TIPA displayed its enhancement effect gradually. Enhancement on strength of limestone portland cement by TIPA was much more significant than portland cement. When TIPA and NaCl were used togehter, the strength of cement were obtained enhancement at both early and later ages.The calorimetry and X-ray diffraction results showed that TIPA could promote the hydration of C4AF to produce AFt. But TIPA had no obvious influence on the hydration of C3S. In limestone portland cement, TIPA promoted the production of AFt. And when gympsum was used up, CaCO3 reacted with hydrated calcium aluminates to produce carbon calcium aluminates. The reaction inhibited the transformation of AFt to AFm.Mercury intrusion results showed that TIPA had air entraining ability, which could increase pore volume in cement paste at early age, especially increased the number of large pores. TIPA’s inherent dispersion reduced the pores and compacted the structure of hydrated cement gel.The influence of TIPA, NaCl and limestone powder on the strength of portland cement was obtained from the fitting regression equation between the three factors and the strength by the method of central composite design (CCD). Their optimum dosages could be easily entracted from the regression equation.