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 本研究评估了将离合器片精加工工序产生的废弃物——研磨粉尘（Grinding Dust, GD）用作胶凝基体缓凝外加剂的可行性。试验中，按照水泥质量的5%、10%和15%的掺量添加该废弃物，并采用维卡仪法测定凝结时间。此外，本研究还分析了该材料对胶凝砂浆流变性能（跳桌试验、挤压流动试验及旋转流变测试）以及硬化胶凝基体物理力学性能的影响。结果表明，随着GD掺量的增加，砂浆凝结时间延长且流动度降低；掺加5%GD的胶凝基体硬化状态性能表现最优。综上可知，GD可有效延缓凝结时间，在不损害基体性能的前提下，具备良好的土木工程应用潜力。