POWRE: Examination of the Mechanisms of ASR Gel Expansion Control by Lithium Additive in Concrete

0074874 KurtisA POWRE奖将支持锂添加剂控制混凝土中碱-硅反应（ASR）膨胀的效果研究。这种反应发生在一些骨料中存在的活性硅酸盐和孔隙溶液碱之间，并产生能够膨胀的碱-硅胶，破坏受影响的混凝土结构。对膨胀控制机制的更透彻理解将为确定在新的和现有的混凝土结构中应使用何种添加剂以何种剂量来避免反应造成的损害提供基础。这项拟议的研究是至关重要的，在这个早期阶段，在她的职业生涯，因为它将使她能够启动一个新的研究领域，同时建立在她现有的知识和技能。拟议的研究的一个关键组成部分是激光扫描共聚焦显微镜（LSCM）的新应用的发展，以检查水泥基材料。通过共聚焦显微镜检查水泥基材料相对未被探索，但由于灵活的样品制备要求，高分辨率和生成三维表示的能力，这种技术提供了很大的希望。由于其视觉冲击力，这些三维模型可以有利地用于技术教育和公共宣传，并已提出了几项活动，包括开发两个简短的教程（一个适合大学教育，一个适合K-12教育）。通过展示这种显微镜技术的实用性，通过深入检查混凝土研究碱硅酸反应，LSCM将在混凝土技术中找到更广泛的应用。 样品制备方案、观察方法和表现形式的发展和完善将使研究者成为水泥基材料创新显微镜的领导者，并可能为PI带来额外的资助机会。

0074874KurtisA POWRE award will support a study of the effects of lithium additives to control expansion by alkali-silica reaction (ASR) in concrete. This reaction occurs between reactive silicates present in some aggregate and pore solution alkalis and produces an alkali-silica gel that is capable of expansion, damaging the affected concrete structure. A more thorough understanding of the mechanisms of expansion control will provide the basis for determining which additives in which dosages should be used in new and existing concrete structures to avoid damage by the reaction. This proposed research is critical for this investigator at this early stage in her career as it will allow her to launch a new research area while building upon her existing knowledge and skills.A key component of the proposed research is the development of the novel application of laser scanning confocal microscopy (LSCM) to examine cement-based materials. Examination of cement-based materials by confocal microscopy has been relatively unexplored, but this technique offers much promise because of the flexible sample preparation requirements, high resolution, and ability to generate three-dimensional representations. Because of their visual impact, these three-dimensional models can be used advantageously in both technical education and public outreach, and several activities have been proposed including the development of two brief tutorials (one appropriate for university education; one appropriate for K-12 education). By demonstrating the utility of this microscopy technique for through-depth examination of concrete to study the alkali-silica reaction, LSCM will find wider applications in concrete technology. Development and refinement of sample preparation protocols, observation methods, and representation formats would establish the investigator as a leader in innovative microscopy of cement-based materials and could lead to additional funding opportunities for the PI.***