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Materials 2018, 11(5), 834; https://doi.org/10.3390/ma11050834

Stability of GO Modified by Different Dispersants in Cement Paste and Its Related Mechanism

Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen Durability Center for Civil Engineering, College of Civil Engineering, Shenzhen University, Shenzhen 518060, China
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Received: 20 April 2018 / Revised: 10 May 2018 / Accepted: 17 May 2018 / Published: 18 May 2018
(This article belongs to the Section Advanced Nanomaterials)
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Abstract

Graphene oxide (GO) is a potential material to be used as a nano-reinforcement in cement matrix. However, a prerequisite for GO to fulfill its function in the cement matrix is homogeneous dispersion. In this study, the effects of three different dispersing agents (DAs), including polycarboxylate-based high range water reducer (P-HRWR), naphthalene-based high range water reducer (N-HRWR), and air entraining agent (AEA) on the dispersion of GO in aqueous solution, simulated concrete pore solution (SCPS), and suspension of cement pastes were sequentially investigated. Results showed that the dispersion effect of GO in aqueous solutions was improved with different DAs. However, the homogeneous dispersion of GO in aqueous solution re-agglomerated in SCPS and suspension of cement pastes. It was concluded that as the cement content and pH of aqueous solutions increased, GOs re-agglomerated and precipitated in an alkaline solution. A possible mechanism was proposed in this study and it was believed that electrostatic interactions and steric hindrance provided by the P-HRWR further made GOs stable in aqueous solutions. The ions and pH of cement pastes increased with the increasing amount of cement, which caused the separation of P-HRWR from GOs. Therefore, GOs were re-agglomerated and absorbed on the surface of the cement particles, resulting in GOs sedimentation. View Full-Text
Keywords: graphene oxide; dispersing agents; agglomeration; cement paste; mechanism graphene oxide; dispersing agents; agglomeration; cement paste; mechanism
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Long, W.-J.; Fang, C.; Wei, J.; Li, H. Stability of GO Modified by Different Dispersants in Cement Paste and Its Related Mechanism. Materials 2018, 11, 834.

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