Retarding effect of grinding dust and its influence on the physical-mechanical and rheological properties of cementitious matrices

Abstract The present study evaluated the feasibility of the use of grinding dust (GD), a waste generated in the clutch disc finishing process, as a retardant additive in cementitious matrices. For this, the waste was added in contents of 5%, 10% and 15%, relative to the cement weight, and the setting time was determined by the Vicat method. In addition, the influence of this material on rheology (flow table, squeeze-flow and rotational rheometry) and on the physical-mechanical properties of the hardened matrices was analyzed. The results indicated an increase in setting time and a reduction in the fluidity of the mortars as a function of the addition of GD and the best results for the hardened state properties were verified for the cementitious matrices containing a 5% addition. Therefore, it was observed that GD is effective in retarding the setting time, presenting great potential for use in civil construction, without impairing its properties.

摘要 本研究评估了研磨粉尘（grinding dust，GD）——离合器片精加工工序产生的工业废料——作为胶凝基材缓凝添加剂的应用可行性。为此，以水泥质量为基准，分别掺入5%、10%和15%的该废料，并采用维卡仪法（Vicat method）测定试样凝结时间。此外，分析了该材料对胶凝基材流变性能（流动台试验、挤压流动试验及旋转流变测试）以及硬化后基材物理力学性能的影响。结果显示，随着GD掺量的提升，砂浆凝结时间延长、流动度降低；且当掺量为5%时，硬化基材的各项性能表现最优。综上，GD可有效延缓胶凝基材的凝结时间，在不损害基材性能的前提下，具备在土木工程领域应用的巨大潜力。