Chu Hongyan, Wang Zifei, Zhang Yu, Wang Fengjuan, Ju Siyi, Wang Lanxin, Wang Danqian
College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China.
Jiangsu Key Laboratory of Construction Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189, China.
Materials (Basel). 2020 Oct 28;13(21):4824. doi: 10.3390/ma13214824.
The fabrication of high-performance cement-based materials has benefited greatly from the extensive use of graphene and its derivatives. This paper studies the effects of graphene sulfonate nanosheets (GSNSs) on sacrificial cement paste and mortar (the tested materials) and other siliceous sacrificial materials, especially their ablation behaviors and mechanical properties. Decomposition temperatures and differential scanning calorimetry were used to examine how different contents of GSNSs determines the corresponding decomposition enthalpy of the tested materials and their ablation behaviors. Molecular dynamics was also used to clarify the mechanism how the GSNSs work in the CSH (calcium silicate hydrated)/GSNSs composite to increase the resistance to high temperature. The experimental results show that: (1) the contents of GSNSs at 0.03 wt.%, 0.1 wt.%, and 0.3 wt.% brought an increase of 10.97%, 22.21%, and 17.56%, respectively, in the flexural strength of siliceous sacrificial mortar, and an increase of 1.92%, 9.16%, and 6.70% in its compressive strength; (2) the porosity of siliceous sacrificial mortar was decreased by 5.04%, 9.91%, and 7.13%, respectively, and the threshold pore diameter of siliceous sacrificial mortar was decreased by 13.06%, 35.39%, and 24.02%, when the contents of GSNSs were 0.03 wt.%, 0.1 wt.%, and 0.3 wt.%, respectively; (3) a decline of 11.16%, 28.50%, and 61.01% was found in the ablation velocity of siliceous sacrificial mortar, when the contents of GSNSs were 0.03 wt.%, 0.1 wt.%, and 0.3 wt.%, respectively; (4) when considering the ablation velocities and mechanical properties of siliceous sacrificial materials, 0.1 wt.% GSNSs was considered to be the optimal amount; (5) the GSNSs contribute to the reinforced effect of GSNSs on CSH gel through the grab of dissociated calcium and water molecules, and the chemical reaction with silicate tetrahedron to produce S-O-Si bonds. These results are expected to promoting the development of new kinds of siliceous sacrificial materials that contain GSNSs.
高性能水泥基材料的制备在很大程度上受益于石墨烯及其衍生物的广泛应用。本文研究了磺酸基石墨烯纳米片（GSNSs）对牺牲性水泥净浆和砂浆（受试材料）以及其他硅质牺牲材料的影响，特别是它们的烧蚀行为和力学性能。采用分解温度和差示扫描量热法来研究不同含量的GSNSs如何决定受试材料的相应分解焓及其烧蚀行为。还利用分子动力学来阐明GSNSs在CSH（水化硅酸钙）/GSNSs复合材料中发挥作用以提高耐高温性的机制。实验结果表明：（1）当GSNSs含量分别为0.03 wt.%、0.1 wt.%和0.3 wt.%时，硅质牺牲性砂浆的抗折强度分别提高了10.97%、22.21%和17.56%，抗压强度分别提高了1.92%、9.16%和6.70%；（2）当GSNSs含量分别为0.03 wt.%、0.1 wt.%和0.3 wt.%时，硅质牺牲性砂浆的孔隙率分别降低了5.04%、9.91%和7.13%，其临界孔径分别降低了13.06%、35.39%和24.02%；（3）当GSNSs含量分别为0.03 wt.%、0.1 wt.%和0.3 wt.%时，硅质牺牲性砂浆的烧蚀速率分别下降了11.16%、28.50%和61.01%；（4）综合考虑硅质牺牲材料的烧蚀速率和力学性能，0.1 wt.%的GSNSs被认为是最佳用量；（5）GSNSs通过捕获解离的钙离子和水分子以及与硅氧四面体发生化学反应生成S-O-Si键，从而对CSH凝胶起到增强作用。这些结果有望推动含GSNSs的新型硅质牺牲材料的发展。
