Pullout tests are commonly used to describe the ultimate shearing resistance developed along the interface between the confining soil and the geosynthetic as a function of normal stress confinement. Pullout tests can also be used to define the complete soil-geosynthetic interface relationship between shear stress and shear displacement interaction. Such a description of interface strength and stiffness characteristics is needed in analytical models used to predict a displacement response of geosynthetic-reinforced soil structures. Due to the extensibility of geosynthetics, data from pullout tests cannot be used directly to calculate strength and stiffness interface properties. The pullout test must be analyzed as a boundary-value problem with appropriate assumptions made regarding the constitutive relationship of the geosynthetic itself and for the interface interaction. An analytical method is presented that allows for the relationship between shear stress and shear displacement to be back-calculated from pullout test data. This method is used to evaluate interface shear stiffness and shear strength for a geogrid and geotextile product for three normal stress confinement levels. The significance of material models used in the formulation is examined.
Departments of transportation use a variety of strategies to maintain roadways effectively during winter while considering a number of factors, such as level of service, cost, infrastructure and environmental impacts, equipment, and weather. The impacts of chemicals on infrastructure, vehicles, and the environment have motivated the State of California to reduce salt usage on highways and to move toward anti-icing strategies, which typically use fewer chemicals to achieve effective results. However, a lack of established recommended dispersal rates, laboratory studies to verify field studies, and an understanding of the science associated with anti-icing principles has slowed full implementation of anti-icing strategies in California. This research effort focused on synthesizing available information regarding winter maintenance best practices and establishing a set of preliminary guidelines to implement anti-icing strategies in California. A qualitative and quantitative evaluation of the performance of five typical anti-icing chemicals was conducted. Performance measures included the temperature at which the snow–pavement bond failed, friction of the pavement surface after snow removal, and snow–pavement bond strength. In general, anti-icing methods used in the laboratory and in full-scale controlled field tests reduced the effort required to remove compacted snow from the pavement surface and improved pavement surface friction after plowing when compared with untreated pavements. A set of guidelines was developed to initiate implementation of anti-icing practices in California. Further assessments are necessary to optimize this methodology on the basis of specific weather conditions and application methods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.