Li Xiaojiao, Yan Tong, Chen Chuanlong, Qiao Xiuchen, Yuan Jin
College of Environment and Ecology, Taiyuan University of Technology, Jinzhong 030600, China.
School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
Materials (Basel). 2025 May 12;18(10):2239. doi: 10.3390/ma18102239.
This study aims to investigate the effects and mechanisms of polycarboxylate superplasticizers (PCEs) on alkali-activated circulating fluidized bed fly ash (CFBFA) materials. Two PCEs-APEG-500 and APEG-2400-were synthesized using allyl polyethylene glycol ethers (APEG) with molecular weights of 500 and 2400, respectively. Their water-reducing performance and impact on the compressive strength of alkali-activated CFBFA materials were evaluated. The results show that both PCEs exhibited significant water reduction (up to 28% for APEG-2400) in pure CFBFA paste systems, but their efficacy was largely diminished in alkali-activated systems. Compared to the control group without PCEs, APEG-500 improved compressive strength by 20.37% at 1 day and 33.00% at 28 days, while APEG-2400 exhibited lower early strength but achieved a 10.31% strength increase at 28 days. Mechanistic analyses via XRD and FTIR analyses indicated that there was no significant alteration in reaction products, suggesting that the shorter side chains of APEG-500 facilitated particle adsorption and accelerated early hydration. Mercury intrusion porosimetry revealed that PCEs refined the pore structure by increasing harmless pores and reducing harmful ones, with APEG-2400 showing an 11.11% higher proportion of harmful pores compared to APEG-500. SEM observations supported these findings. This study clarifies the relationship between PCE molecular weight and CFBFA material properties, providing a basis for optimizing CFBFA-based cementitious materials.
本研究旨在探究聚羧酸系高效减水剂（PCEs）对碱激发循环流化床粉煤灰（CFBFA）材料的影响及其作用机制。分别采用分子量为500和2400的烯丙基聚乙二醇醚（APEG）合成了两种PCEs——APEG - 500和APEG - 2400。评估了它们的减水性能以及对碱激发CFBFA材料抗压强度的影响。结果表明，在纯CFBFA浆体体系中，两种PCEs均表现出显著的减水效果（APEG - 2400高达28%），但在碱激发体系中其效果大幅降低。与未添加PCEs的对照组相比，APEG - 500使1天抗压强度提高了20.37%，28天抗压强度提高了33.00%，而APEG - 2400早期强度较低，但在28天时强度提高了10.31%。通过XRD和FTIR分析进行的机理分析表明，反应产物没有显著变化，这表明APEG - 500较短的侧链促进了颗粒吸附并加速了早期水化。压汞法显示，PCEs通过增加无害孔和减少有害孔来细化孔隙结构，与APEG - 500相比，APEG - 2400的有害孔比例高11.11%。SEM观察结果支持了这些发现。本研究阐明了PCE分子量与CFBFA材料性能之间的关系，为优化基于CFBFA的胶凝材料提供了依据。
