Three-dimensional electrical tomography for imaging large concrete members

混凝土结构是英国和国际民用基础设施，城市景观，废物控制设施等的普遍和关键组成部分。从安全性、耐久性、经济性和环境角度来看，我们现在比以往任何时候都更需要混凝土结构。例如，仅在英国，就有大约67，400座承载重型货车的公路桥，其中70%以上是钢筋混凝土、预应力混凝土或混凝土涵洞桥。其中，近70%是在1960年至1990年间建造的。考虑到这些信息，仅在英国，更换或修复老化的国家桥梁的成本就非常巨大。例如，委员会管理的（在英国）公路桥梁的维修积压总额估计为67亿英镑。这表明，英国议会管理的混凝土桥梁目前积压了47亿英镑的维修工作。与拆除和重建这些桥梁有关的费用估计比目前的维修积压大约高出两个数量级。因此，切实解决当代具体基础设施挑战需要的不仅仅是货币解决方案，还需要技术创新。为了开始解决老化混凝土基础设施的需求，我们必须首先能够可靠地评估混凝土结构在其寿命期间的状况，以便，例如，在更换或停止服务之前恢复他们。然而，目前许多无损检测/结构健康监测（NDT/SHM）成像方法提供的有关混凝土结构内部状况的信息有限。该项目通过确定用于评估混凝土结构构件（如梁、板和柱）的状况和健康的新3D方法（电气断层扫描）的可行性来应对这一问题。该项目的成果有可能使（i）钢筋混凝土构件的基本行为的实验研究，使研究人员能够量化“看到”暴露在极端环境和/或负载条件下的内部构件和（ii）定量的三维条件监测建造混凝土结构。从资产管理的角度来看，这种非破坏性技术将使维护人员能够“看到”混凝土结构的内部。在这样做时，维护人员可以检测内部损坏，如开裂和钢筋腐蚀，并在危及安全或导致需要更换整个结构的昂贵系统问题之前修复/更换单个构件。

Concrete structures are ubiquitous and critical components of UK and international civil infrastructure, cityscapes, waste containment facilities, and much more. Now, more than ever, we demand more from our concrete structures, from safety, durability, economy, and environmental perspectives. For example, in the UK alone, there are approximately 67,400 highway bridges carrying heavy goods vehicles and over 70% are reinforced concrete, prestressed concrete, or concrete culvert bridges. Of these, nearly 70% were built between 1960 and 1990. Given this information, the cost of replacing or remediating ageing national bridges in the UK alone is huge. For example, the total maintenance backlog for council-managed (in Great Britain) road bridges has been estimated to be £6.7bn. This indicates that council-managed concrete bridges in Great Britain are currently in a £4.7bn maintenance backlog. The costs associated with deconstructing and reconstructing these bridges can be estimated as a figure approximately two orders of magnitude larger than the current maintenance backlog. Therefore, feasibly addressing contemporary concrete infrastructure challenges requires more than a monetary solution, it requires technical innovation. To begin addressing the demands of an ageing concrete infrastructure, we must first be able reliably assess the condition of concrete structures during their lifespan in order to, e.g., rehabilitate them before replacement or discontinuing service before failure. At present, however, many non-destructive testing/structural health monitoring (NDT/SHM) imaging methods offer limited information regarding the internal condition of concrete structures. This project responds to this issue by determining the feasibility of a new 3D approach (electrical tomography) for use in assessing the condition and health of concrete structural members, such as beams, slabs, and columns. Outcomes from the project have the potential to enable (i) experimental studies of the fundamental behaviour of reinforced concrete members by allowing researchers to quantifiably "see" inside members exposed to extreme environmental and/or loading conditions and (ii) quantitative 3D condition monitoring of constructed concrete structures. From an asset management perspective, this non-destructive technology would allow maintainers to "see" inside concrete structures. In doing this, maintainers can detect internal damage, such as cracking and reinforcement corrosion, and repair/replace individual members before they jeopardise safety or give rise to expensive systematic problems requiring replacement of the entire structure.