Effect of Molecular Weight of Polycarboxylate-type Superplasticizer on the Rheological Properties of Cement Pastes

• Published in: Polymers & polymer composites Vol. 20; no. 8; pp. 725 - 736
• Main Authors: Peng, Xiongyi, Yi, Conghua, Qiu, Xueqing, Deng, Yonghong
• Format: Journal Article
• Language: English
• Published: Shrewsbury Rapra 01.01.2012; Sage Publications Ltd. (UK); Sage Publications Ltd
• Subjects: Applied sciences; Cements; Cements, Adhesive; Chemical properties; Composites; Composition; Dispersing; Efficiency; Exact sciences and technology; Forms of application and semi-finished materials; Identification and classification; Laminates; Low molecular weights; Molecular weight; Molecular weights; Pastes; Physicochemistry of polymers; Plasticizers; Polycarbonates; Polymer industry, paints, wood; Polymers; Rheological properties; Rheology; Technology of polymers; Viscosity; China; Carboxylate polymer; Polyelectrolyte; Adsorption; Preparation; Superplasticizer; Polymer; Electrokinetic potential; Apparent viscosity; Rheological properties
• ISSN: 0967-3911; 1478-2391
• DOI: 10.1177/096739111202000808

In order to study the effect of molecular weight of polycarboxylate-type superplasticizer (PC) on the rheological properties of cement pastes, PCs with different molecular weights (low, medium, high) were synthesized, and used as superplasticizers for cement suspensions. The effect of molecular weight of PC on the zeta potential, adsorption, and rheological behaviour of the corresponding cement suspensions were investigated systematically. Among the PCs, PC with a medium molecular weight always produced the lowest apparent viscosity for cement pastes at the same shear rate. Compared to PC with a low molecular weight, PC with a high molecular weight presented a stronger initial dispersing ability and a weaker dispersing stabilizing ability for cement pastes. In addition, PC with a low molecular weight had an advantage over PC with a high molecular weight for reducing the viscosity of paste in the low added dosage or low water/cement ratio, but the latter had the advantage of reducing the viscosity of the paste when the added dosage or water/cement ratio was high. This understanding of the rheological properties of cement pastes incorporating PC will provide an important reference for the application and synthesis of PC with high efficiency.