Wang Shiheng, Zhao Peng, Tian Yaogang, Liu Jianan
School of Materials Science and Engineering, Chang'an University, Xi'an 710061, China.
Polymers (Basel). 2024 Sep 30;16(19):2769. doi: 10.3390/polym16192769.
This study aimed to utilize the hydration characteristics of cement through wet grinding techniques to efficiently and conveniently prepare a stable C-S-H seed suspension, providing key parameters and a scientific basis for their large-scale production, which ensures the stability of the C-S-H suspension during production, transportation, and application. This preparation aimed to mitigate the adverse effects of high-volume silica fume on the early mechanical properties of high-performance cement concrete. The properties of C-S-H seed were characterized in detail by SEM, XRD, and TD. In the concrete performance test, silica fume was used to replace part of the cement, and different contents of C-S-H seed were added to test its effect on the compressive strength of concrete, with XRD and SEM used to analyze the performance differences. The results show that the particle size and hydration degree of cement no longer developed after 90 min of wet grinding. Polycarboxylate ether (PCE) superplasticizer can increase the fluidity of the crystal C-S-H seed suspension when the content exceeds 1.5%. When the content of PCE exceeded 2%, the C-S-H seed suspension precipitated. Adding 5% C-S-H seed can increase the compressive strength of cement concrete by 10% under the condition of reducing the amount of cement and increasing the amount of silica fume. And Ca(OH) (CH) was produced by cement hydration consumed by silica fumes to generate C-S-H gel, by which the concrete became denser with more strength. However, when the amount of C-S-H seed exceeded 7%, the compressive strength of the concrete decreased.
本研究旨在通过湿磨技术利用水泥的水化特性，高效便捷地制备稳定的C-S-H晶种悬浮液，为其大规模生产提供关键参数和科学依据，确保C-S-H悬浮液在生产、运输和应用过程中的稳定性。这种制备方法旨在减轻大量硅灰对高性能水泥混凝土早期力学性能的不利影响。通过扫描电子显微镜（SEM）、X射线衍射仪（XRD）和热重分析仪（TD）详细表征了C-S-H晶种的性能。在混凝土性能试验中，用硅灰替代部分水泥，并添加不同含量的C-S-H晶种以测试其对混凝土抗压强度的影响，同时用XRD和SEM分析性能差异。结果表明，湿磨90分钟后水泥的粒径和水化程度不再发展。当聚羧酸醚（PCE）高效减水剂含量超过1.5%时，可提高C-S-H晶种悬浮液的流动性。当PCE含量超过2%时，C-S-H晶种悬浮液会沉淀。在减少水泥用量并增加硅灰用量的情况下，添加5%的C-S-H晶种可使水泥混凝土的抗压强度提高10%。硅灰消耗水泥水化产生的氢氧化钙（Ca(OH)₂）生成C-S-H凝胶，使混凝土变得更致密且强度更高。然而，当C-S-H晶种用量超过7%时，混凝土的抗压强度会降低。
