有机染料辅助分散氧化石墨烯及其对水泥砂浆强度和耐久性的影响

Effect of organic dye assisted dispersion of graphene oxide on mechanical properties and durability of cement mortar

研究了采用有机染料罗丹明B(RhB)辅助聚羧酸减水剂(PCE)分散氧化石墨烯(GO)及其对水泥砂浆强度和耐久性的影响。通过吸光度试验、Zeta电位及AFM表征研究了RhB对GO在饱和氢氧化钙(CH)溶液中的分散性能,结果表明在掺入少量RhB情况下可以大幅度提升GO在CH溶液中的分散性,且当GO与RhB质量比为1∶2时,GO的分散效果最佳。力学强度测试表明,在RhB的辅助分散下,当GO掺量为水泥质量的0.03wt%时,28天抗折、抗压强度相较于不掺入RhB的GO砂浆试件提升最大分别为14.78%、33.29%。耐久性试验表明RhB能促进GO在水泥水化产物的模板作用,使结构更为致密,减少受冻融与硫酸盐的侵蚀,耐久性能显著提高。微观测试表明RhB的加入可以促进GO调控水化产物生长的作用,明显减少内部结构孔洞、裂缝等缺陷。本文提供了一种引入低成本的有机染料来提升GO在水泥孔隙液中的分散性能,具有许多潜在的应用价值。

The dispersion of graphene oxide(GO)with organic dye rhodamine B(RhB)assisted polycarboxylic acid water reducer(PCE)and its effect on the strength and durability of cement mortar were studied.The dispersion of GO in saturated calcium hydroxide(CH)solution by RhB was studied by absorbance test,Zeta potential,and AFM characterization.The results show that the dispersion of GO in CH solution could be greatly improved when a small amount of RhB was added,and the dispersion effect of GO is the best when the mass ratio of GO to RhB is 1∶2.The mechanical strength test shows that the maximum increase of 28 days flexural and compressive strength are 14.78%and 33.29%respectively under the auxiliary dispersion of RhB compared with the GO mortar specimens without RhB,when the content of GO is 0.03wt%of the mass of cement.The durability test shows that RhB could promote the template effect of GO on cement hydration products,make the structure more compact,reduce the corrosion by freeze-thaw and sulfate,and significantly improve the durability.The microscopic test shows that the addition of RhB could promote the role of GO in more regulating the growth of hydration products,and the defects such as internal structure holes and cracks are significantly reduced.This work provides a method to introduce low-cost organic dyes to improve the dispersion performance of GO in cement pore solution,which has many potential applications.