没食子酸协同聚羧酸减水剂分散氧化石墨烯及其对水泥砂浆性能的影响

The Synergistic Effect of Gallic Acid and Polycarboxylic Water-reducer on Aqueous GO Dispersion and the Enhanced Mechanical Properties of Cement Mortar Composites

少量氧化石墨烯(GO)可大幅度提升水泥基材料的强度和韧性,但GO极易在高钙高碱水泥水化介质中聚沉,解决GO的分散稳定性问题是发挥其对水泥基材料增强功效的关键。本工作研究了没食子酸(GA)对GO在饱和氢氧化钙(CH)溶液中的助分散作用及其对GO掺配水泥砂浆力学性能的影响。相对于聚羧酸减水剂(PC)单独分散GO体系,额外加入一定比例的GA能进一步改善GO在CH溶液中的稳定分散能力;与PC分散GO的基准试件相比,少量的助分散剂GA可使水泥砂浆3 d的抗折、抗压强度分别提高17.3%和18%,28 d的抗折、抗压强度分别提高19.2%和21.4%。GA协同PC分散GO具有更好的促进水泥水化进程的作用,可使硬化水泥石的微观结构更加密实,水泥水化产物晶体更加有序规整生长。本研究以绿色廉价的GA作助分散剂,为GO增强水泥基材料提供了一种全新的思路且具有潜在的应用前景。

Asmall amount of graphene oxide(GO)could greatly improve the strength and toughness of cement composites.However,GO was easy to accumulate and precipitate in the environment of high calcium and alkali,so the stability of GO dispersion is the key to obtain high-perfor-mance cement-based materials.In this study,the effect of GA on the dispersion of GO in the saturated CH solution and mechanical properties of hardened cement composite were studied.Compared with PC dispersing system,the addition of a certain content of GA could further improve the dispersing ability of GO in CH solution and subsequently enhanced the flexural and compressive strength of cement mortar in 3 d by 17.3%and 18%,and in 28 d by 19.2%and 21.4%,respectively.The synergistic effect of GA and PC on the GO dispersion could obviously accelerate cement hydration process and uniform growth of the crystal of cement hydration products,which made the microstructure of hardened cement stone more compact.Herein,as a green and inexpensive reagent,GA was choosen as a co-dispersant to provide a new alternative to GO reinforcing cement-based materials and had many potential applications.