Wang Jian, Huang Kaijian, Chu Hongyan, Li Jianhui
College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China.
Materials (Basel). 2025 May 28;18(11):2541. doi: 10.3390/ma18112541.
Anti-washout admixtures (AWAs) are a unique component of underwater non-dispersive concrete (UNDC), which gives the concrete the ability to remain undispersed in water. On some special occasions, freshly mixed underwater non-dispersive concrete is exposed to the erosion of moving water, and conventional acrylamide-based AWAs are only suitable for static water or the water flow rate is small. In this study, the inorganic component nanosilica (NS) is modified, treated, and copolymerized with the organic components acrylamide (AM) and acrylic acid (AA) to form an inorganic-organic hybrid polymer with a hyperbranched structure, which changes the linear structure of the original polyacrylamide molecule, and we optimize the synthesis process. The polymers are characterized at the microscopic level and their compatibility with polycarboxylic acid water-reducing agents (SP) is investigated. In addition, the polymers are compared and evaluated with commonly used PAM in terms of their working performance. The experimental results indicated that under specific process conditions, polymers endow cement mortar with good resistance to water erosion. At the same time, the polymers' three-dimensional network structure is prominent, with good compatibility with SP and better anti-dispersity. The microstructure of the cement paste with added polymers is dense and flat, but its flowability and setting time are slightly worse. This study provides a new development direction for the development of AWAs under a dynamic water environment, which has specific engineering significance.
抗冲刷外加剂（AWAs）是水下不分散混凝土（UNDC）的一种独特组分，它使混凝土具有在水中保持不分散的能力。在一些特殊场合，新拌制的水下不分散混凝土会受到流动水的冲刷，而传统的基于丙烯酰胺的AWAs仅适用于静态水或水流速度较小的情况。在本研究中，对无机成分纳米二氧化硅（NS）进行改性、处理，并与有机成分丙烯酰胺（AM）和丙烯酸（AA）共聚，形成具有超支化结构的无机-有机杂化聚合物，改变了原聚丙烯酰胺分子的线性结构，并优化了合成工艺。对聚合物进行微观表征，并研究其与聚羧酸减水剂（SP）的相容性。此外，将该聚合物与常用的PAM在工作性能方面进行比较和评价。实验结果表明，在特定工艺条件下，聚合物赋予水泥砂浆良好的抗水冲刷性能。同时，聚合物的三维网络结构突出，与SP相容性良好，抗分散性更佳。添加聚合物的水泥浆体微观结构致密平整，但其流动性和凝结时间略差。本研究为动态水环境下AWAs的发展提供了新的发展方向，具有特定的工程意义。
