Nanomaterials are becoming widely used in cement to enhance the properties of cement-based materials. Artificially synthesized nano-C-S-H serves as a nucleation site for the hydration product C–S–H gel, facilitating its formation. This is deemed as an early strength agent to effectively promote cement hydration. Introducing comb-like polycarboxylate ether (PCE) during the synthesis of C–S–H can effectively reduce the size of C–S–H, resulting in better early strength effects. In this study, the acid-ether ratio of PCE is set at 6:1, and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) substitutes acrylic acid (AA) at varying molar ratios to obtain modified PCE. Calcium silicate hydrate seed-polycarboxylate ether (C-S-Hs-PCE) is synthesized using co-precipitation technique. This study investigated impacts of AMPS on the particle size of C-S-Hs-PCE and the early strength of cement-based materials using dynamic light scattering analysis, total organic carbon analyzer, X-ray diffraction analysis, low-field nuclear magnetic resonance, scanning electronic microscopy, isothermal calorimeter, and compressive strength testing. The results show that the C-S-Hs-PCE, synthesized at an AMPS to AA molar ratio of 5:95, turns out to possess a reduced particle size compared to use of PCE without AMPS. This is pivotal in promoting the hydration of the silicate phase and the formation of calcium hydroxide and C–S–H gel in the paste, and thereby reducing the total porosity while improving the early mechanical strength of the mortar, especially within first 24 h.

中文翻译：

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2-丙烯酰胺-2-甲基丙磺酸对水合硅酸钙种子早期强度增强的影响

纳米材料正在广泛应用于水泥中，以提高水泥基材料的性能。人工合成的纳米CSH作为水合产物C-S-H凝胶的成核位点，促进其形成。这被认为是有效促进水泥水化的早强剂。在C-S-H合成过程中引入梳状聚羧酸酯醚（PCE），可以有效减小C-S-H的尺寸，从而获得更好的早期强度效果。本研究将PCE的酸醚比设定为6:1，用2-丙烯酰氨基-2-甲基丙磺酸(AMPS)以不同摩尔比替代丙烯酸(AA)，得到改性PCE。采用共沉淀技术合成了水合硅酸钙种子-聚羧酸醚（CS-Hs-PCE）。本研究利用动态光散射分析、总有机碳分析仪、X射线衍射分析、低场核磁共振、扫描等方法研究了AMPS对CS-Hs-PCE粒径和水泥基材料早期强度的影响。电子显微镜、等温量热仪和抗压强度测试。结果表明，与使用不含 AMPS 的 PCE 相比，以 AMPS 与 AA 摩尔比为 5:95 合成的 CS-Hs-PCE 具有较小的粒径。这对于促进硅酸盐相的水合作用以及在浆体中形成氢氧化钙和 C-S-H 凝胶至关重要，从而降低总孔隙率，同时提高砂浆的早期机械强度，特别是在前 24 小时内。