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Early age performance of latex-modified concrete bridge deck overlays

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dc.contributor.advisor Lundy, James R.
dc.creator Sujjavanich, Suvimol
dc.date.accessioned 2012-10-01T18:50:59Z
dc.date.available 2012-10-01T18:50:59Z
dc.date.copyright 1996-11-27
dc.date.issued 1996-11-27
dc.identifier.uri http://hdl.handle.net/1957/33993
dc.description Graduation date: 1997 en_US
dc.description.abstract Environmental factors and physical properties of latex modified concrete (LMC) are hypothesized to contribute to early age cracking in bridge deck overlays. Cracking permits the ingress of moisture and aggressive solutions into the substrate and may contribute to other subsequent distresses. Understanding the material properties and mechanisms involved is necessary to minimize these distresses. This research consisted of a two part study: first, the development of LMC strength and fracture properties at ages ranging from 5 hours to 28 days was studied, and secondly, the effects of the environment on LMC distresses were modelled. Environmental conditions: temperature, solar energy, and wind speed were determined from weather records. A fracture mechanics based model, the Fictitious Crack Model (FCM), incorporating finite element analyses and superposition techniques was employed with material properties from the first part of study on LMC performance. Different bilinear strain softening diagrams were used to predict fracture performance at different ages. The predictions agreed well with the test data. The impacts of temperature differentials on crack development were studied. The shrinkage effect was also indirectly incorporated through the temperature analysis. The material properties study indicated significant changes in strength, deformability and fracture properties, particularly during the early age. The developments differ slightly from conventional concrete. Test results indicated a significant improvement in reducing and bridging microcracks, especially in the prepeak-load region. Fracture toughness and deformability increased significantly with time. Fracture energy varied from 2.3 to 133.1 N/m, depending on age, and to some degree, on notch depth ratio. In the second stage, the FCM provided a reasonable prediction for crack initiation and propagation when only temperature effects are of concern. Age, surface conditions and structural restraint strongly affect crack resistance of the overlays. Only slight effects were observed from the overlay thickness in the study range (51-76 mm). Shallow preexisting cracks possibly reduce the crack resistance of the overlay about 30 percent. A prolonged moist cure for 48 hours after placing is suggested to reduce the risk of cracking. With available environmental information, it is possible to develop guidelines for appropriate environmental conditions for LMC bridge deck construction to minimize the risk of early age cracking. en_US
dc.language.iso en_US en_US
dc.subject.lcsh Bridges, Concrete -- Cracking en_US
dc.subject.lcsh Concrete -- Additives en_US
dc.subject.lcsh Concrete -- Analysis en_US
dc.subject.lcsh Polymer-impregnated concrete en_US
dc.title Early age performance of latex-modified concrete bridge deck overlays en_US
dc.type Thesis/Dissertation en_US
dc.degree.name Doctor of Philosophy (Ph. D.) in Civil Engineering en_US
dc.degree.level Doctoral en_US
dc.degree.discipline Engineering en_US
dc.degree.grantor Oregon State University en_US
dc.description.digitization File scanned at 300 ppi (Monochrome, 256 Grayscale, 24-bit Color) using Capture Perfect 3.0 on a Canon DR-9050C in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR. en_US
dc.description.peerreview no en_us

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