The setting and hardening process of concrete can be considered as the most critical time period during the life of a concrete structure. To assure high quality and avoid problems in performance throughout the life of the material, it is essential to have reliable information about the early age properties of the concrete. This paper presents a new method to monitor the hydration process of cementitious materials at early ages. The technique is based on the measurement of the reflection coefficient (or reflection loss) of high frequency shear waves at an interface between a steel plate and e.g. concrete. Several experimental studies that examine the ability of the wave reflection method to qualitatively and quantitatively describe the setting and hardening process of cement paste, mortar and concrete are presented. The results show that parameters such as setting time, compressive strength, elastic and visco-elastic moduli and degree of hydration of cementitious materials can reliably monitored with the wave reflection method. The relationship between the measured reflection loss and the compressive strength was successfully used in a first field trial of the method to determine the inplace strength of precast concrete elements.

Inspection of bridges in the United States has been regulated by the federal government since 1968, when a national bridge inspection program was established that recognized the need for periodic and consistent bridge inspections. The first National Bridge Inspection Standards (NBIS) were developed in 1971. Since then, inspection standards, policies, and procedures have continued to evolve. This paper describes some of the recent changes and trends with bridge inspection practices in the United States.

Many researchers called for a need to expose L2 learners to diverse writing contexts, and L2-L2 interactions using English as a communication tool became more common than communication with native English speakers. The present study introduced two groups of Korean university students to a task, for which they were grouped differently: the first with a group of students at a Chinese university and the second with Chinese students as well as students of a different Korean university. These groups performed a task that they selected from among three choices. In the process of their e-mail exchanges, the students' pre- and post-task perspectives were explored through two surveys. In addition, the students expressed their reflections regarding this experience in writing. Overall, the students seemed to consider this experience of exchanging emails with L2 students speaking a different L1 useful and it helped some students gain confidence in their ability to use English as a communication tool. This study provided an opportunity to expand the writing context in EFL classrooms.