Use of Graphene Oxide to Improve the Durability and Mechanical Properties of Mortar Immersed in Flowing River for Three Years.

Keren Zheng,Hao Wei,Xiaobao Zuo,Dong Cui,Qiannan Wang

doi:10.3390/nano10122385

Abstract

Nanomaterials have received increased concentration in the field of civil engineering, as their incorporation can effectively modify the mechanical and transport properties of cementitious composites. In this study, to understand the effect of graphene oxide (GO) nanoparticles on the durability and mechanical properties of cementitious composites serving underwater, mortars incorporated with GO were taken for study. To match the real circumstance, all specimens were immersed directly in a flowing river for three years, and their transport properties, mechanical properties and microstructure before, and after, river experience were studied separately. The results showed that the incorporation of GO could reduce both early-age permeation coefficient and later-age chloride migration coefficient of mortar specimens. The average porosities of mortars could be reduced by the range of 3.37–11% with GO incorporation. Moreover, through a novel dual-scan method, GO incorporation was confirmed effective in enhancing both the leaching and cracking resistance. Furthermore, the compressive strengths, flexural strengths and splitting tensile strengths could be improved by the range of 4.37–9.82%, 7.78–22.33%, 8.14–28.73%, respectively with GO incorporation, and the tested mechanical strengths for GO-incorporated mortar after three-year river experience could be retained to a higher extent. Finally, based on durability and mechanical properties, the optimum mix proportion of GO was determined to be 0.06 wt.% in this study. The work presented here is of high reference value for the designing of marine infrastructure and can help promote the application of nanomaterials in civil engineering.

Highlights

In recent decades, the construction of bridges, dams, ports and tunnels, such as Hong Kong-Zhuhai-Macao bridge, Bohai bay cross-sea channel, Banpo port, etc., has been carried out massively in developing countries
It should be noted here, the microstructure of mortar specimen at early ages was quite fragile, and several movements such as casting, demolding and transferring could all cause cracking inside the sample
The results suggested significant extents of leaching in GO0 and GO30, and that could be supported by the porosity results revealed through dual Computed Tomography (CT) scan

Summary

Introduction

The construction of bridges, dams, ports and tunnels, such as Hong Kong-Zhuhai-Macao bridge, Bohai bay cross-sea channel, Banpo port, etc., has been carried out massively in developing countries. During years of service underwater, the marine infrastructures have become vulnerable towards the actions of waves, undercurrents, tides and other kinds of waterflows, and these water actions can cause gradual deterioration on concrete durability, leading to shortened service life of the whole infrastructure [1,2,3]. In real circumstances, marine infrastructures is vulnerable towards the actions of waves, undercurrents, tides and other water actions, and their effects on concrete durability are non-ignorable. Hu et al [12] embedded cylindrical mortar specimens in pipes, and used 1 M ammonium chloride solution of variant speeds to flush along the pipe Both the microstructure and chemical composition of specimens before, and after, flushing were tested, based on which the effects of flowing solutions on concrete properties were studied. To systematically uncover the mechanism of durability degradation for concrete serving underwater, carrying out in-site tests is indispensable

Methods

Results

Conclusion