Visual inspection of fire-damaged concrete based on terrestrial laser scanner data

Abstract

Visual condition survey and inspection is typically the initial method employed in the assessment of concrete damaged by fire, and it is among the most significant non-destructive testing methods. In spite of visual inspection being simple in principle, it is capable of providing cardinal information about the condition of the fire-damaged structure and act as a basis upon which subsequent and detailed assessment methods can be founded. When concrete is exposed to various elevated temperatures, it undergoes change in its physical characteristics among others, and indicators such as change in surface texture, cracks, spalling and colour change become evident. These indicators of fire-damaged concrete can be assessed using visual inspection methods and further assessed with more advanced methods in a case where detailed investigations are needed. In this study, visual inspection of terrestrial laser scanner data of fire-damaged concrete was investigated by modelling and analysing laser intensity. An analysis of the generated intensity images from laser intensity data has proved useful and valuable in the visual inspection of concrete before and after heating. Furthermore, laser scanner geometric data has been used in the assessment of concrete surface roughness before and after heating.