Yang Lei, Wang Pengfei, Luo Shuqiong, Wang Yaxin, Xu Shengye
Henan Key Laboratory of Materials on Deep-Earth Engineering, School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China.
Guangdong Grid Energy Development Corp., Ltd., Guangzhou 510000, China.
Polymers (Basel). 2025 Jun 22;17(13):1738. doi: 10.3390/polym17131738.
The utilization of red mud by blending it into cement paste is still facing poor workability issues due to the finer particle size and higher water absorption of red mud, which can be solved by the addition of polycarboxylate superplasticizer (PCE) to effectively maintain the working performance. However, the specific mechanisms by which different topologies of PCEs, in terms of water-reducing (WR)- and slump-retaining (SR)-type PCEs, influence red mud blended cement paste require further clarification. This research investigates the effect of WR-PCE and SR-PCE on the rheological properties, mechanical properties, and microscopic morphology of red mud blended cement paste under different red mud contents. The results demonstrated that at saturated dosages of 0.5% WR-PCE and 0.75% SR-PCE, both types of PCEs improved paste fluidity and reduced plastic viscosity and shear stress. Moreover, the time-dependent fluidity loss rate of the SR-PCE-incorporated paste was lower to that of the WR-PCE-incorporated paste at 30 and 60 min. With 0% and 25% red mud contents, the compressive strengths at 1, 3, 7, and 28 days were higher for WR-PCE than for SR-PCE due to the enhanced hydration of CS and CS. Furthermore, hydration products in the WR-PCE-incorporated paste were more uniformly distributed compared to the SR-PCE-incorporated paste. However, a 50% red mud content negatively impacted paste strength, likely due to the high alkalinity destabilizing the PCE. This study aims to elucidate the mechanistic relationship between PCE topology and the improved performance of red mud blended cement paste.
由于赤泥的粒径更细且吸水率更高，将其掺入水泥浆体中使用时仍面临工作性差的问题，而添加聚羧酸系高效减水剂（PCE）可以有效解决这一问题，从而保持其工作性能。然而，不同拓扑结构的PCE，即减水型（WR）和保坍型（SR）PCE，影响赤泥掺合水泥浆体的具体机制仍需进一步阐明。本研究考察了WR-PCE和SR-PCE在不同赤泥掺量下对赤泥掺合水泥浆体的流变性能、力学性能和微观形貌的影响。结果表明，在0.5% WR-PCE和0.75% SR-PCE的饱和掺量下，两种类型的PCE均提高了浆体的流动性，降低了塑性粘度和剪切应力。此外，在30分钟和60分钟时，掺入SR-PCE的浆体的随时间的流动性损失率低于掺入WR-PCE的浆体。在赤泥掺量为0%和25%时，由于CS和CS的水化增强，WR-PCE在1天、3天、7天和28天的抗压强度高于SR-PCE。此外，与掺入SR-PCE的浆体相比，掺入WR-PCE的浆体中的水化产物分布更均匀。然而，50%的赤泥掺量对浆体强度有负面影响，这可能是由于高碱度使PCE失稳所致。本研究旨在阐明PCE拓扑结构与赤泥掺合水泥浆体性能改善之间的机理关系。
