Browsing by Author "Conway, Ryan"
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Item Portland Cement Concrete Pavement Thickness And Shear Wave Velocity Variation Versus Observed Pavement Distresses(2017-02) Conway, RyanConcrete slab thickness is the key design characteristic of a concrete pavement. It is the most important design parameter and the major focus of control and inspection during construction. It is widely accepted that thickness deficiencies can reduce performance. In order to investigate possible correlations between Portland cement concrete (PCC) thickness with observed surface distresses, a combination of non-destructive ultrasonic thickness tests and distress surveys were performed on three existing highways prior to their rehabilitation. In addition to concrete thickness, concrete shear wave velocity was also measured in ultrasonic tests. Statistical and visual analysis were performed in order to investigate possible correlations between thickness and velocity variation and observed distress. The results of these analyses were inconclusive for thickness variation, but showed highly significant correlation for shear wave velocity. Investigation of the design documents for the some of the survey areas showed that the shear wave velocity survey was able to identify design changes which have significant impact on pavement performance. A methodology for the implementation of a shear wave velocity survey for identification of design changes which may influence pavement performance is presented.Item Portland Cement Concrete Pavement Thickness Variation Versus Observed Pavement Distress(Minnesota Department of Transportation, 2016-09) Khazanovich, Lev; Hoegh, Kyle; Barnes, Randal; Conway, Ryan; Salles, LucioBenefits from a potential significant correlation between distresses and slab thickness can be broadly applied in all stages of highway development from design and construction to maintenance decisions. In order to comprehensive explore this possibility, thickness data and existing distresses were related for three highway projects in Minnesota. Thickness was obtained through non-destructive ultrasonic testing, while distresses were recorded for the same location with a distress image software. Significant thickness variation was observed in both longitudinal and transverse directions. The combined results of thickness, shear wave velocity and distresses analysis revealed that an increase in shear wave velocity was coincident with a less damaged pavement area within a section. An in-depth statistical analysis confirmed this observation showing that shear surface velocity variation was better correlated with overall pavement performance than thickness variation. Differences in cracking behavior within a section were traced back to changes in construction and design practices, showing the potential of using shear velocity analysis for pavement maintenance. A survey and analysis procedure for shear wave velocity testing of concrete pavements is proposed.