For applications in cement-based materials, studies on carbon-based nanomaterials have been almost exclusively on carbon nanotubes, carbon nanofibers, and graphite oxide. Graphene sheets (GPs), as a kind of carbon-based nanomaterials, show unusual mechanical, electrical, optical, and other properties. In this paper, the main focus is to enhance the effect of GPs by improving dispersion through ultrasonication and use of surfactant. Then, dispersion and stability are quantitatively measured by comparing absorbance spectra through spectrophotometry and qualitatively observed through digital imaging and SEM imaging. Therefore, the dispersing protocol is optimized and the most effective and stable dispersion is achieved. At last, the piezoresistivities under compressive load of GPs/cement composites pastes at different additions of GPs are studied by comparing with plain cement paste.

    Abstract
    1 Introduction
    2 Experimental methods and procedures
        2.1 Materials
        2.2 Experimental methods
    3 Experimental results and discussion
        3.1 Quantitative evaluation of the dispersion of GPs
        3.2 Morphology of the surfactant-treated GPs
        3.3 Piezoresistivity of GPscement composite
    4 Conclusions
    Acknowledgements 
    References

• Siyue Zhu(School of Civil Engineering and Architecture, Wuhan Polytechnic University)
• Xiantao Qin(School of Civil Engineering and Architecture, Wuhan Polytechnic University)
• Zuxu Zou(School of Civil Engineering and Architecture, Wuhan Polytechnic University)
• Rongtang Zhang(School of Civil Engineering and Architecture, Wuhan Polytechnic University)
• Yi Jiang(School of Civil Engineering and Architecture, Wuhan Polytechnic University, School of Building Construction Management, Purdue University)