Title: Influence of Carboxylic Acid-Carboxylic Ester Ratio of Carboxylic Acid Ester Superplasticizer on Characteristics of Cement Mixtures
Author(s): G. Ferrari, T. Cerulli, P. Clemente, M. Dragoni, M. Gamba,
and F. Surico
Publication: Symposium Paper
Appears on pages(s): 505-520
Keywords: adsorption; cement; superplasticizer
Carboxylic acid ester superplasticizers (CAE) consist of polymers in which hydrophilic polyoxyethylene ester chains (CE) are grafted onto a main chain bearing carboxylic groups (CA). In the present work, CAE copolymers characterized by different molar carboxylic acid - carboxylic ester ratios (CAKE) were synthesized and evaluated as super-plasticizers by using two different cements. The efficiency of CAE copolymers as superplasticizers was found to be dependent on the carboxylic acid - carboxylic ester ratio (CAKE) and the optimum CA/CE value in order to attain the best flowability was different for the two cements. Adsorption measurements indicated an increase of adsorption onto both the cements by increasing CAKE. On the other hand, zeta potential of cement pastes was not substantially influenced by the addition of the different superplasticizers. The results of the present work seem to indicate that both adsorption and steric stabilization are the main factors which determine the performances of CAE as superplasticizers and that CA/CE is an important parameter influencing the cement/CAE superplasticizer compatibility.