Impact of Molecular Structure of Polycarboxylate Based Superplasticizer on Hydration Behavior of C3S
Liu Jiaping,Yu Yinhui,Ran Qianping,Qiao Min and Gao Nanxiao
DOI:10.3969/j.issn.1674-4764.2013.02.025
Received ,Revised , Accepted , Available online July 01, 2015
Volume ,2013,Pages 153-158
- Abstract
Isothermal calorimeter, thermal analysis and scanning electron microscope were employed to investigate the impact of 3 polycarboxylate based superplasticizers (PCs) on the hydration behavior of tricalcium silicate (C3S). In addition, adsorption isotherm was measured by total organic carbon. The results indicate that PCs extends the induction period of C3S. Initial hydration process of C3S is markedly retarded, whereas acceleration is observed in the period of 28 d. And it is found that PC1, with maleic anhydride for its main chain, has the strongest retardation effect. The majority of the copolymer dispersants is remained in the pore solution. Moreover, linear relationship between the content of COO- and its retardation effect is established. Accordingly it is presumed that the critical supersaturation with respect to portlandite can be expected to have a profound impact because of the addition of PCs.