Evaluation Of The Grinding Effect Of Alkanolamines And Its Influence On Alite Hydration

The grinding effects can be quantitative evaluated from the curve of the grinding aids dosage to the 45μm square hole sieve, distribution index and warter demand of the cement grinding to get the same specific surface area(350 to 360m2/kg) in mill. The point defined as saturation point which the 45μm square hole sieve, distribution index and warter demand of the cement will not chang when the grinding aids dosage increase.The abscissa correspond to the saturated dosage,and the ordinate correspond to the strongest grinding effects. When the dosage of grinding aids below the saturation dosage, with the increasing of grinding aids dosage, the sieve residue of 45μm square hole sieve will gradually reduce ,the warter demand and distribution index will gradually increase, the grinding effect gradually strengthen.When the dosage of grinding aids achieve saturation dosage, with the increasing of grinding aids, , the grinding effect unchanged. The less the 45μm square hole sieve, the more distribution index and warter demand of the cement correspond to saturation point,the stronger the grinding effect. The less saturation point the stronger the grinding effect when the 45μm square hole sieve, distribution index and warter demand is the same. Through the experiment results, the sieve residue of 45μm square hole sieve will be prior. The grinding effect of Triethanolamine, Triisopropanolamine and Ethylene glycol is Triethanolamine> Triisopropanolamine >Ethylene glycol.The grindability of materials will affect the grinding effect. Adding 8.0% additive equivalence instend clinker, take the sieve residue of 45μm square hole sieve as the evaluation index of grinding effect : cement will have narrow particle size distribution as the mixing of slag, and will have wide particle size distribution as the mixing of limestone. the grinding effect of triisopropanolamine to the cement mix lime stone is better than the grinding effect to the cement with slag,and the grinding effect to the cement with slag is better than the cement with no additive.For the enhance mechanism of grinding aids, the main point is mostly alkanolamines grinding aids promote the hydration of C3A or C4AF. It is very significance to investigate the effect of alkanolamines to the hydration of Alite which has the greatest contribution to the strength of cement.Through the analysis of the bound water,hydration heat and DTA– TG, investigated the effect of Triethanolamine, Triisopropanolamine and Ethylene glycol to the hydration of Alite.The results show that Alite have more bond water, hydration heat and faster hydration rate because of the mixing of alkanolamines before the age of 28 days,and close to blank samples after 28 days. Triethanolamine and Triisopropanolamine make the composition of hydration products of Alite different from the blank sample, The proportion of crystal to scolloid of Alite hydration is below to the blank sample,and it is equal to blank sample when adding Ethylene glycol. So Triisopropanolamine not only strengthen the 28d compressive strength of cement mortar but also strengthen the long age compressive strength of cement mortar.