A grindability model for grinding aids and their impact on cement properties

This paper describes the grindability of four kinds of grinding aids – triethanolamine (TEA), propylene glycol (PG), calcium lignosulfonate (CLS) and sodium tripolyphosphate (STPP) – and their impact on cement properties. Experiments were carried out on cement samples to determine the specific surface area and sieve residue, on cement paste to determine the normal consistency, setting time and heat release, and on cement mortar to assess the compressive and flexural strength. The results showed that the increment of specific surface area (ΔS) at 30 min and decrement of 30 μm sieve residue (Δη) for the four kinds of grinding aids showed an exponential function with an increase in dosage. TEA, CLS and STPP showed good grindability to cement clinker, while PG even showed some negative grindability. Through the chemical action of the grinding aids and their impact on particle size distribution of the cement samples, TEA and PG were found to accelerate the heat release rate, while CLS and STPP delayed it. TEA enhanced early mortar strength. CLS increased both the early and late mortar strength. STPP showed no remarkable impact on mortar strength while PG was found to decrease the mortar strength.