The gradual evolution of the material properties of a cement-based material, i.e. the stiffness of cement paste, is the result of the continuous change of the microstructure with the progress of the hydration process. Based on an existing micromechanical model for the simulation of the shear and elastic modulus of...
The Center for Advanced Cement-Based Materials (ACBM) is a consortium of researchers from: Northwestern University, University of Illinois at Urbana-Champaign, Purdue University, The University of Michigan, and The National Institute of Standards and Technology. This ACBM update contains information on the article "A better Maturity Meter?" by Surendra P. Shah...
The setting and hardening process of concrete is considered to be the most critical time period during the life of a concrete structure. Previous research has been conducted on an ultrasonic wave reflection method that utilizes a steel plate embedded in the concrete to measure the reflection loss of shear...
The nondestructive, in-situ testing of early-age concrete properties is a crucial point for the progress of many construction projects in the building sector. The application of such techniques can establish e.g. the earliest possible form removal from concrete construction elements, thereby opening highways to traffic or releasing prestress from steel...
The U.S. has 542,000 bridges that consume billions of dollars per year in construction, rehabilitation and maintenance funds and which are the lifelines of U.S. commerce. The 1992 ISTEA (fntermodal Surface Transportation Efficiency Act) mandates the implementation of a quantitative computerized bridge management system by I 996. A prime need...
This report describes the results of applying acoustic emission (AE) testing to the trunnion shafts of the East Span of the 1-5 Interstate Bridge. The tests were done at the request of Oregon DOT personnel to determine if active fatigue racks are present in the subject shafts.
The in-depth inspection by WIDOT detected two sites that had visible cracks in the stiffener-to-hanger diaphragm welds, the east side of Hanger 6 in the north tie girder, and the east side of Hanger 4 in the south tie girder. Additionally, many ultrasonic indications were detected by WIDOT in the...
The segmental prestressed concrete box girder of Koror-Babeldaob (KB) Bridge in Palau, which had the record span of 241 m (791 ft.), presents a striking paradigm of serviceability loss due to excessive multi-decade deflections. The data required for analysis have recently been released and are here exploited to show how...
A study is conducted to determine the effects on the early hydration kinetics and
compressive strength by seeding of Portland cement and alkali-activated blast furnace
slag with a pure form of calcium silicate hydrate (C-S-H). The effects of C-S-H seeding
during the early nucleation and growth period of each type...
Neuroscience research has made many important contributions to the study of the brain and behavior. Perhaps because of these contributions the general public seems to be easily seduced by neuroscientific explanations. Meaning that when a scientific article is paired with a brain image, the information within the article is automatically...
Which areas of Chicago have greater concentrations of lead in their water and is that associated with environmental racism? Since Chicago is racially segregated, the marginalized areas such as the south side and west side are more likely to contain high levels of lead.
Humans are unique in their ability to think abstractly (e.g. using language, learning relations). Previous work from our lab has shown that infants can learn simple abstract relations, like whether two objects are the “same” or “different”. In this study, we investigated flexibility in early learning. Our question was whether...
Aim to facilitate the production of the treatment by optimizing reproducibility and minimizing cost. Tasks: Find cost/time effective way to reach end product, Perfecting technique to increase yield, Adjusting known procedure when necessary, Molecule compliant with drug-like properties (Lipiphilic, Ingestible, Long half-life)
Research questions: Do students face pressure to choose certain racial identities in different social spheres on campus? What identities are selected in what situations? What struggles are faced by those of more than one race on Northwestern’s campus? What privileges are associated with being a multi-racial student at Northwestern University?...