Adsorption of Admixtures on Portland Cement Hydration Products

Abstract

The adsorption of calcium lignosulfonate and salicylic acid was studied on the hydration products of the four principal components of portland cement. To investigate the adsorption as a function of development of hydration product, the determinations were made after varying hydration times. The times allowed were from 5 min to 24 hr for tricalcium aluminate (C 3 A) and tetracalcium aluminoferrite (C 4 AF) and from 1 hr to 28 days for β‐dicalcium silicate (β‐C 2 S) and tricalcium silicate (C 3 S). Samples were characterized with respect to surface area and poresize distribution. The effect of gypsum on the adsorption was also investigated. The results indicate that the amounts of salicylic acid and calcium lignosulfonate adsorbed on the hydration products of C 3 A, and of calcium