This presentation contains information about the project "The future of transportation... and how we'll pay for it" by Joseph L. Schofer, Department f Civil & Environmental Engineering. The presentation was delivered at the 40th Anniversary Seminar Day at Northwestern University on April 18, 2009.
Gentrification - the process in which higher income (and often younger) households displace lower income residents of a city neighborhood - has been occurring in many urban neighborhoods over the last few decades. This process changes the demographics, and often the essential character, of the neighborhood. As a result, we...
This presentation contains information on the project "Aligning Data to Support Transportation Decisions, Emerging Challenges & Opportunities for the Data World". The presentation was delivered by Joseph L. Schofer at Transportation Research Board – AASHTO Peer Exchange meeting on May 15-16, 2008.
The paper deals with the behavior of fluid cement pastes, formulated from Self Consolidating Concretes (SCCs), and the experimental correlation of fundamental rheological properties, such as the yield stress and the viscosity, with measurements from field tests, such as the mini-cone slump flow test. As a matter of fact, several...
The concrete currently used in the slip-form paving process is a low slump concrete that requires both internal and external vibration in order to achieve satisfactory compaction. The use of vibrator fingers for the internal vibration often leads to trails on the surface of the pavement and to segregation around...
This presentation contains information on the keynote paper "Health Monitoring of Early Age Concrete". The presentation was delivered by Surendra P. Shah at CONSEC'04 in Seoul, Korea on June 30, 2004.
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...
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 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...
In this paper, the correlation of reflection loss measured by an ultrasonic shear wave reflection
method and the microstructure in cement-based material is investigated. Three cement pastes
(Portland cement type I) with different water-cement ratios (0.35, 0.50 and 0.60) cured at 25
°C were examined. The ultrasonic shear wave reflection...
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...
This article summarizes an investigation of the structural response of a brick façade home in New Mexico. The subject Ricter residence was located some 1100 to 1400 ft away from an aggregate quarry, and was subjected to a maximum peak particle velocity and air blast over pressure of 0.29 ips...
Cracking is one of the most common concerns cited by owners of structures adjacent to construction or mining blasting. While a large database of case studies documenting the relative insignificance of ground motion induced by responsible blasting compared to weather effects on cracks in nearby structures has been established, the...
Surveillance of large geotechnical projects requires autonomous collection of data from a wide range of instrument types. An equally large range of data formats are employed by these measurement systems. A data exchange protocol is needed to make field data available for interpretation on a variety of platforms. This paper...
Blasting and climatological response of cracks are compared for structures constructed of concrete block typical of home construction in Europe. While much has been written comparing micrometer crack response of wood frame structures typical of residential construction in North America, little has been written concerning response of structures more typical...
Carbonation, a neutralizing reaction in cement paste, can be used to date cracks in cementitious materials. Currently, comparison between two cracks is the only method available to predict a relative age with carbonation. These two crack studies require a crack of known age in a similar material with similar exposure...
This paper summarizes micro-inch response of cosmetic cracks in a typical slab-ongrade ranch style house to both construction equipment-induced vibration and environmental (weather) effects. This structure was instrumented, and its response studied as part of the development of an Autonomous Crack Measurement (ACM) system. ACM systems are intended to record...
Concern over construction vibration-induced cracking has led to development of a new approach to vibration monitoring called autonomous crack measurement (ACM) and illustrated in Figure 1. This paper describes the concept as well as sensor performance in the first test house fitted an ACM system. Response of three cracks in...