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Our study used a natural experiment to compare a project-based cornerstone course with the traditionally-taught introductory course in civil engineering. During the study, two sections of the course were organized around an overarching project, the design of an event center, and the remaining sections used guest lectures, a textbook, and traditional laboratory activities to familiarize students with civil engineering. Students in the project-based course gained more on measures of creativity and design self-efficacy on a survey of engineering identity than traditionally-taught students. Pre/post comparisons of the project-based students confirmed gains in design self-efficacy, but indicated a decrease in mathematical self-efficacy. In interviews students indicated that they recognized and appreciated that the project-based course enabled them to do real engineering, speaking to the development of engineering identity. They expressed concerns, however, that they might not be learning de-contextualized science and mathematics, a possible explanation for the decrease in mathematics efficacy.

Asphalt emulsions and cutbacks are mainly used for surface preservation treatments and as bonding layer during pavement construction. Cutback and emulsion residues are routinely evaluated to ensure specification compliance for quality control and assurance purposes. The current test methods for residue recovery of asphalt emulsions and cutbacks are resource intensive, have a low throughput, and require distillation apparatus with a large lab footprint. This study developed two separate test methods that are simple and repeatable for emulsion and cutback residue recovery using a vacuum oven with the ultimate goal that these tests can be used for routine testing. These methods recover small quantity of the residue that is adequate to perform one test with 25 mm plate using dynamic shear rheometer (DSR). This study examines the repeatability of the new method by (1) using a variety of different grades obtained from different suppliers for both cutbacks and emulsions; and (2) participation of two laboratories with different brands of equipment. The mass loss during the residue recovery and the DSR parameter G*/sinδ were used to examine repeatability. The results show that the test methods developed are repeatable between the replicates and between the two participating research laboratories. [ABSTRACT FROM AUTHOR]

There is limited information on the characteristics and performance of paving mixtures made with 100% bio-binders. Moisture damage resistance of this type of mixture is a concern since the components of the bio-binder may have a higher affinity with water than asphalt binders. In this context, this paper presents a moisture damage susceptibility evaluation of wood-based bio-binder-aggregate interfaces in terms of energy parameters calculated from surface free energy components. The bio-binder was used as a total replacement for asphalt binders, and the responses were compared to a neat- and a highly modified-asphalt binder, considering different aggregate sources. Results suggest the bio-binder has similar moisture damage resistance to the neat asphalt binder and higher resistance than the highly modified asphalt binder, providing a first indication for the potential use of this bio-binder as 100% asphalt binder replacement. However, additional research is still required to validate these findings at the mixture level. [ABSTRACT FROM AUTHOR]