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

0074874KurtisA power奖将支持锂添加剂对控制混凝土中碱-硅反应（ASR）膨胀的影响的研究。这种反应发生在某些骨料中的活性硅酸盐和孔隙溶液碱之间，并产生一种能够膨胀的碱硅胶，破坏受影响的混凝土结构。对膨胀控制机制的更彻底的了解将为确定在新的和现有的混凝土结构中应使用何种剂量的添加剂以避免反应造成的破坏提供基础。这项拟议的研究对该研究人员在其职业生涯的早期阶段至关重要，因为它将使她能够在现有知识和技能的基础上启动一个新的研究领域。提出的研究的一个关键组成部分是开发激光扫描共聚焦显微镜（LSCM）的新应用，以检查水泥基材料。用共聚焦显微镜检查水泥基材料相对来说还没有被探索过，但是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。由于其视觉效果，这些三维模型可以在技术教育和公共宣传中得到有利的使用，并且已经提出了一些活动，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对混凝土进行深入检查以研究碱-硅反应的效用，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.***