Browsing by Subject "Fracture properties"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Asphalt Mixture and Binder Fracture Testing for 2008 MnROAD Construction
    (Minnesota Department of Transportation, 2009-12) Marasteanu, Mihai; Moon, Ki Hoon; Turos, Mugurel
    This report summarizes the results of an experimental effort to characterize the low-temperature behavior of asphalt mixtures and binders from the recently reconstructed cells at the MnROAD facility. In depth analysis of the data was not part of this study; this will be accomplished in several concurrent research projects.
  • Thumbnail Image
    Item
    Investigation of Low Temperature Cracking in Asphalt Pavements National Pooled Fund Study – Phase II
    (Minnesota Department of Transportation, 2012-08) Marasteanu, Mihai; Buttlar, William; Bahia, Hussain; Williams, Christopher; Moon, Ki Hoon; Teshale, Eyoab Zegey; Falchetto, Augusto Cannone; Turos, Mugurel; Dave, Eshan; Paulino, Glaucio; Ahmed, Sarfraz; Leon, Sofie; Braham, Andrew; Behnia, Behzad; Tabatabaee, Hassan; Velasquez, Raul; Arshadi, Amir; Puchalski, Sebastian; Mangiafico, Salvatore; Buss, Ashley; Bausano, Jason; Kvasnak, Andrea
    The work detailed in this report represents a continuation of the research performed in phase one of this national pooled fund study. A number of significant contributions were made in phase two of this comprehensive research effort. Two fracture testing methods are proposed and specifications are developed for selecting mixtures based on fracture energy criteria. A draft SCB specification, that received approval by the ETG and has been taken to AASHTO committee of materials, is included in the report. In addition, alternative methods are proposed to obtain mixture creep compliance needed to calculate thermal stresses. Dilatometric measurements performed on asphalt mixtures are used to more accurately predict thermal stresses, and physical hardening effects are evaluated and an improved model is proposed to take these effects into account. In addition, two methods for obtaining asphalt binder fracture properties are summarized and discussed. A new thermal cracking model, called "ILLI-TC," is developed and validated. This model represents a significant step forward in accurately quantifying the cracking mechanism in pavements, compared to the existing TCMODEL. A comprehensive evaluation of the cyclic behavior of asphalt mixtures is presented, that may hold the key to developing cracking resistant mixtures under multiple cycles of temperature.
  • Thumbnail Image
    Item
    Protocols and Criteria for Acoustic Emission Monitoring of Fracture-Critical Steel Bridges
    (Center for Transportation Studies, University of Minnesota, 2015-06) Tillmann, Anton S.; Schultz, Arturo E.; Campos, Javier E.
    With bridge infrastructure in Minnesota aging, advancing techniques for ensuring bridge safety is a fundamental goal of the Minnesota Department of Transportation (MnDOT). Developing health monitoring systems for fracture-critical bridges is an essential objective in meeting the stated goal. This report documents the implementation of two, 16-sensor, acoustic emission monitoring systems in one of the tie girders of the Cedar Avenue Bridge, which is a fracture-critical tied arch bridge spanning the Minnesota River between Bloomington and Eagan, MN. The goal of the project is to develop a process for using acoustic emission technology to monitor one of the girders of the bridge while continuously collecting data from the monitoring systems. Given the cost of acoustic emission sensing equipment, an approach was adopted to space the sensors as widely as possible. Fracture tests were conducted on a specimen acoustically connected to the bridge to simulate fracture in a bridge member. Sets of criteria were developed to differentiate between acoustic emission data collected during fracture and ambient bridge (i.e. AE noise) data. The sets of criteria were applied to fracture test data and AE noise data to determine the validity of the criteria. For each criteria set, a period of Cedar Avenue Bridge monitoring data was analyzed. The results of the analysis of each period showed that the criteria could differentiate between the bridge AE noise data and the fracture test data. The AE noise data never met all of the criteria in the set, whereas all criteria were met during each of the applicable fracture tests.