热还原氧化石墨烯在水泥水化介质中的分散及其增强砂浆的性能与机理研究

Dispersion of Thermally Reduced Graphene Oxide in Simulated Hydrated Cement Environment and Study on Performance and Mechanism of Graphene Reinforced Mortar

掺配纳米石墨烯能大幅度提升水泥基材料的各项性能,但如何改善石墨烯纳米片层在水泥水化的高钙高碱性环境中的稳定分散是一个难点。本工作以一种聚多芳香环类减水剂(JS)作为分散剂,通过测定吸光度研究了高温热还原法制备的还原型氧化石墨烯(rGO)在用于模拟水泥水化高钙高碱性环境的饱和氢氧化钙(CH)溶液中的稳定分散性。研究表明,当JS分散剂与胶凝材料质量比为1.5%时,rGO在CH溶液中有相当好的分散效果。石墨烯掺配水泥砂浆的力学性能测试表明,当rGO掺量为0.05%时,3 d抗折、抗压强度分别提高了9.5%、11.1%,28 d抗折、抗压强度分别提高了6.74%、26.5%。化学结合水试验及微观测试表明,JS分散剂能使rGO有效均匀地分布在水泥石中,加速水泥水化进程,进而调控水化产物晶体生长。

Graphene nanosheets can greatly improve the properties of cement-based materials,but how to improve the dispersion of graphene nano-sheets in calcium and alkaline-abundant cement hydration environment is a key problem.In this study,a polyaromatic water reducer(JS)was used as a dispersant to study the dispersion of reduced graphene oxide(rGO)prepared by high temperature thermal reduction in saturated calcium hydroxide(CH)solution used to simulate hydrated cement system rich in calcium and alkaline environment.The study showed that when the mass ratio of JS to cement was 1.5%,rGO could be well-dispersed in CH solution.The mechanical test of graphene-mixed cement mortar showed that when the mass content of rGO to cement was 0.05%,the 3 d flexural and compressive strength were increased by 9.5%and 11.1%,respectively and the 28 d flexural and compressive strength were increased by 6.74%and 26.5%respectively.The chemical bonded water and microscopic tests showed that JS could effectively disperse rGO in hardened cement motar,accelerate the hydration process of cement paste and regulate the crystal growth of hydrated products.