Current understanding of cellulose ethers impact on the hydration of C3A and C3A-sulphate systems

The impact of cellulose ethers (CE) on C(3)A hydration was examined to support the understanding of the retarding effect of CE on cement hydration. In this sense, we successively studied the CE adsorption on ettringite and calcium hydroaluminates, and then the CE influence during C(3)A hydration in presence or absence of calcium sulphate. We emphasized a phase-specific adsorption of CE depending on CE chemistry. Besides, in addition of CE, we highlighted a gradual slowing down of C(3)A dissolution as well as ettringite and calcium hydroaluminates precipitation. Again, a great impact of CE chemistry and CE adsorption behaviour were noticed. Thus, HECs induce always a stronger adsorption on calcium hydroaluminates and a longer C3A hydration delays than HPMCs. (C) 2009 Elsevier Ltd. All rights reserved.