An optical strain measurement system for asphalt mixtures

Birgisson, Björn; Montepara, Antonio; Romeo, Elena; Roncella, R.; Roque, Reynaldo; Tebaldi, Gabriele

doi:10.1617/s11527-008-9392-8

Cited by 59 publications

(14 citation statements)

References 12 publications

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“…In that case, the perspective differences between homologous points are negligible. In other words, the very same methodology used in traditional digital image correlation (DIC) applications (see, for instance, Birgisson et al 2009) can be used for landslide surface-point tracking (SPT) (see Scaioni et al (2014b)). Once the displacement of a landslide point is recovered in image space, a back-projection of its former and latter position onto the DSM can reconstruct the movement in the object space.…”

Section: Surface Point Trackingmentioning

confidence: 99%

A Fixed Terrestrial Photogrammetric System for Landslide Monitoring

Roncella

Forlani

2015

Modern Technologies for Landslide Monitoring and Prediction

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Though landslide alert is based on monitoring systems capable of high frequency, highly accurate, continuous-operation photogrammetry has been used since long time to periodically control the evolution of landslides. In this chapter, a fixed terrestrial stereo photogrammetric system is presented. It has been developed to monitor landslides and, in general, changes in digital surface model (DSM) of the scene framed by the cameras. The system is made of two single-lens reflex (SLR) cameras, each contained in a sealed box and controlled by a computer that periodically shoots an image and sends it to a host computer. Once an image pair is received, the DSM of the scene is generated by digital image correlation on the host computer and made available for archiving or analysis. The system has been installed and is being tested on the Mont de la Saxe landslide, where several monitoring systems are active and provide reference data. Instability of the camera attitude has been noticed and corrected with an automated procedure by image resampling. First comparisons with interferometric synthetic aperture radar data show a good agreement of the displacements over time.

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Section: Surface Point Trackingmentioning

confidence: 99%

A Fixed Terrestrial Photogrammetric System for Landslide Monitoring

Roncella

Forlani

2015

Modern Technologies for Landslide Monitoring and Prediction

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“…MDTT strains were evaluated using a completely redesigned in-house developed DIC software code called DICe, which was initially designed to facilitate the quantification of strains in the mastic in between the aggregates in a typical asphalt mixture (Birgisson et al 2009). The new DICe software code implements, for the image correlation step, a fairly innovative Least Squares Matching approach that uses higher order polynomial shape functions to model the displacement field between the reference and the measured image of the DIC sequence: proposed also by other authors in different application fields (Bethmann and Luhmann 2010).…”

Section: Fracture Identification and Strain Analysismentioning

confidence: 99%

“…observation data snooping) are harder to be applied, and lower levels of accuracy can be expected. The previous DIC system has shown to achieve satisfactory accuracy compared to strain gauges, resulting in 0.04 % accuracy in compressive/tensile strains and 0.03 % accuracy in shear strains [further details on the method are discussed elsewhere, Birgisson et al (2009)]. In this case, due to the peculiar, localized, behavior of the mastic, it's hard to perform the same comparison with the new technique.…”

Section: Fracture Identification and Strain Analysismentioning

confidence: 99%

“…The cracking behavior of the mastics was investigated using a Modified Direct Tension Test (MDTT) developed at the University of Parma (Montepara et al 2011). Strain localization and damage distribution were observed using a completely redesigned in-house developed DIC software code called DICe, which was initially designed to facilitate the quantification of strains in the mastic in between the aggregates in a typical asphalt mixture (Birgisson et al 2009). Finally, the interaction between binder and filler was investigated using a X-ray diffractometer to analyze possible crystallographic alteration in the fillers when mixed with the asphalt binder.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Mineral Fillers and Their Fractional Voids on Mastic Rheological and Mechanical Properties

et al. 2015

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Mineral fillers are added into asphalt mixtures to stiffen asphalt binder and improve mixture density and strength. The stiffness of the mastic affects the ability of the mixture to resist permanent deformation at higher temperatures, influences stress development and fatigue resistance at intermediate temperatures, and influences stress development and fracture resistance at low temperatures. In this study, the effect of mineral fillers and their fractional voids on mastic rheological and mechanical properties is evaluated. Four types of filler with different physical properties were investigated. The fillers were associated to four asphalt binders, including unmodified and polymer modified binders, to obtain 16 asphalt mastics. The rheological properties of the mastics were evaluated conducting Superpave testing procedures, including the dynamic shear rheometer (DSR) and the bending beam rheometer (BBR). Their mechanical response was investigated using a Modified Direct Tension Test (MDTT), also employing a completely redesigned in-house developed Digital Image Correlation System (DIC) capable of accurately capturing localized or non-uniform stress distributions. The results showed that the Rigden fractional void is an effective indicator of filler stiffening effect, but it cannot be employed to evaluate the interaction between asphalt binder and filler. The effect of filler volume fraction on mastic performance depends on the binder employed.

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“…[10][11][12]. A problematic aspect of the DIC is that its resolution depends inversely upon the observation window; that is, the imaged field-of-view must be a few millimeters in size for attaining the resolution level equivalent to the aforementioned sensors.…”

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confidence: 99%