The slag cement has the advantages of low heat of hydration, high strength at the later stage, inhibition of alkali aggregate reaction, and resistance to sulfate corrosion. It has been used in a large number of projects. When producing slag cement, the slag is less abrasive than the clinker. So the best active particle size cannot be achieved during common grinding, and separate grinding will cause a lot of energy consumption, so it is used in the grinding process. Grinding aid to reduce grinding energy consumption and improve cement performance.
Triethanolamine (TEA) and Triisopropanolamine (TIPA), as the main components of commonly used grinding aids, have a strong polarity, which can reduce the free energy on the surface of cement particles, prevent particle agglomeration, and increase particles. The specific surface area can also accelerate the hydration rate of clinker minerals. So how does slag cement behave under the action of TEA and TIPA?
(1) Both TEA and TIPA can reduce the fineness of slag cement, increase the specific surface area, increase the content of fine particles, and increase the water demand of the cement, but the effect on the setting time is small.
(2) TEA and TIPA significantly enhance the strength of slag cement. The strength of slag cement increases with the increase in the amount of grinding aids. The 28d compressive strength of cement with 0.05% TIPA can increase by 5. 58MPa. The strengthening effect of TIPA on slag cement is significantly better than TEA.
(3) Under the action of TEA and TIPA, the hydration rate of slag cement is accelerated, and the types of hydration products are unchanged, but the number is increased and the crystallinity is better. These hydration products are cross-linked to form a more dense structure.