Location of steel reinforcement in concrete using ground penetrating radar and neural networks

Development of a new in situ test method to measure the air permeability of high performance concretes

“…However, it is not safe to assume at all times that pre-specified durability levels are achieved on site, as ultimate engineering concrete properties are not solely related to materials, mix proportions and service environments, but also factors which are difficult to control on site, such as manufacturing and delivery processes, as well as construction practices employed from initial placement to final curing [4,8,9]. As a result, a correlation between performance assumptions and in situ construction quality should ideally be considered.To ensure the ultimate delivery of high performance in practice, on site evaluation is essential and so were many field techniques proposed [10][11][12][13][14]. Amongst these, assessment of concrete's near-surface permeation characteristics is recognised as a reliable tool to qualify durability [4,10,14,15], because deterioration of reinforced concrete usually involves ingress of aggressive substances from the surrounding environment [3,5,7,11].…”

Electromagnetic Sensing Techniques for Non-Destructive Diagnosis of Civil Engineering Structures

“…As a consequence, the GPR technique is useful for the study of bedrock stratigraphy and cavity detection (Lazzari et al 2006), groundwater and pollution (Chianese et al 2006), metal and plastic pipelines such as cables in urban areas, archaeological finds ) when low central frequency antennas are used. On the contrary, when high central frequency antennas are used, the GPR, more properly named in this case Surface Penetrating Radar (SPR), can be considered a NDT technique (McCann and Forde 2001) providing precious information about the presence of "embedded" objects such as, reinforced rebars (Shaw et al, 2005;Che et al, 2009), but also embedded "defects" such as voids and, by using special antennas (Huston et al, 2000;Forest and Utsi, 2004;Utsi et al, 2008), fractures. Moreover, the GPR technique can contribute to determine the concrete moisture content (Shaari et al, 2004;Hugenschmidt and Loser, 2008; GPR survey design is a crucial issue since it determines not only the possibility to detect the target (rebar, defect, water infiltration, ecc.…”

Validated ground penetrating radar simulation model for estimating rebar location in infrastructure monitoring

“…Due to the nature of the received echoes, analysis of a radargram is nontrivial. For example, rebar -which can be simplified as a point reflector, causes a characteristic hyperbolic response, illustrated in Figure 1 [5].…”