该研究探讨了 MCC 对经过干燥和密封固化的 OPC 和 AAM 基质的流变行为、微观结构构建、水合动力学和早期强度(长达 7 天)的影响。流变测量表明,MCC 的添加提高了 OPC 基体的粘度恢复性和触变性。虽然 MCC-OPC 基质的粘度随着屈服应力变化相对较小而增加,但由于 MCC 含量从 0.25% 增加到 1%,MCC-AAM 的屈服应力急剧增加,在 15 分钟内高达 2.2 倍。这归因于 MCC 在 NaOH 中的凝胶化和溶胀。随着MCC剂量的增加,MCC-OPC在前24小时内的水化动力学严重延迟(1%MCC约5.3小时),而AAM的水化动力学对MCC剂量不太敏感,归因于接触 NaOH 后 MCC 中氢键的断裂。研究结果还表明,MCC 的添加减少了 AAM 水合 7 天后的放热,因为它对飞灰溶解有抑制作用。MCC-OPC 的早期抗压强度随着 MCC 含量的增加而持续降低,在 1% MCC 用量下最大降低 21%。与 OPC 基质相比,基于 MCC 的 AAM 的抗压强度对固化条件和 MCC 用量的敏感度较低。研究结果表明,MCC 可以成为一种强大的混合物,用于改变 OPC 和 AAM 基质的流变性和硬化,同时为纺织和生物质废物的升级回收提供途径。由于其对飞灰溶解的抑制作用。MCC-OPC 的早期抗压强度随着 MCC 含量的增加而持续降低,在 1% MCC 用量下最大降低 21%。与 OPC 基质相比,基于 MCC 的 AAM 的抗压强度对固化条件和 MCC 用量的敏感度较低。研究结果表明,MCC 可以成为一种强大的混合物,用于改变 OPC 和 AAM 基质的流变性和硬化,同时为纺织和生物质废物的升级回收提供途径。由于其对飞灰溶解的抑制作用。MCC-OPC 的早期抗压强度随着 MCC 含量的增加而持续降低,在 1% MCC 用量下最大降低 21%。与 OPC 基质相比,基于 MCC 的 AAM 的抗压强度对固化条件和 MCC 用量的敏感度较低。研究结果表明,MCC 可以成为一种强大的混合物,用于改变 OPC 和 AAM 基质的流变性和硬化,同时为纺织和生物质废物的升级回收提供途径。
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Effect of microcrystalline cellulose on fresh stage and early-age properties of Portland cement-based and alkali-activated slag-fly ash blend
The research examines the influence of MCC on the evolution of rheological behaviour, micro-structural build-up, hydration kinetics and early-age strength (up to seven days) of OPC and AAM matrices subject to dry and sealed curing. Rheological measurements show that the addition of MCC improves recoverability of viscosity and thixotropy of OPC-based matrices. While viscosities of MCC-OPC matrices increase with relatively low change in yield stress, MCC- AAM shows drastic increase in yield stress, up to 2.2 folds within 15 min, due to an increase in MCC content from 0.25% to 1%. This is attributed to gelation and swelling of MCC in NaOH. Hydration kinetics of MCC-OPC in the first 24 h is severely retarded with increase in MCC dosage (about 5.3 h for 1% MCC), while that of AAM is less sensitive to MCC dosage, attributed to rupture of hydrogen bonds in MCC after exposure to NaOH. The findings also show that addition of MCC reduces the heat evolution of AAM after seven days of hydration, due to its suppressing effect on fly ash dissolution. Early-age compressive strength of MCC-OPC consistently reduces with increase in MCC content, registering a maximum reduction of 21% at 1% MCC dosage. Compressive strength of MCC-based AAM is less sensitive to curing conditions and the dosage of MCC than OPC matrices. The findings suggest that MCC can be a powerful admixture for modifying rheology and hardening of OPC and AAM matrices, while providing an avenue for upcycling textile and biomass wastes.