Impact of the mixer and time of mixing on the properties of industrialized mortar

Abstract Industrialized rendering mortars usually employ additives in their formulations, most commonly air-entraining agents. In order to ensure quality and production scale, they are prepared in manufacturing units with precise control of the formulation and dosage of raw materials and additives. Despite the control in the production of this material in an industrial environment, variations in the mixing conditions may affect the level of air incorporation. On construction sites, mortars are usually either processed manually or with the use of mixing equipment. This study evaluates the impact of the type of equipment and mixing time on air incorporation in industrialized mortars and the effect on their properties after hardening. The results indicate that the incorporation of air results from the adjustment between the mixing equipment and the mortar formulation. Different sensibilities of mortars to the type of equipment have been identified. That fact indicates that an alternative to reduce variability on the level of air incorporation in building sites depends on the development of formulations with minimal sensibility to the mixing process.

摘要：工业化饰面抹灰砂浆（rendering mortars）的配方中通常会掺入外加剂，其中最常用的为引气剂（air-entraining agents）。为保障产品质量与生产规模，此类砂浆会在具备精准管控能力的专业生产厂区内制备，对原材料及外加剂的配方与投料剂量进行严格把控。尽管在工业化生产环境中已对该材料的生产流程加以管控，但搅拌条件的波动仍可能影响其含气量（air incorporation）水平。在建筑施工现场，砂浆通常采用人工搅拌或借助搅拌设备进行拌合。本研究评估了设备类型与搅拌时长对工业化砂浆含气量的影响，以及该因素对硬化后砂浆性能的作用。研究结果显示，含气量的调控效果取决于搅拌设备与砂浆配方之间的匹配性。研究还发现不同砂浆对设备类型的敏感程度存在差异。这一现象表明，若要降低建筑施工现场含气量水平的波动幅度，其可行路径在于开发出对搅拌过程敏感度极低的砂浆配方。