Evaluate the Effect of Waste Ground Rubber Tire Powder in Hot Mix Asphalt
In the present study, the effect of waste ground rubber tire powder (WGRTP) modifier on various mechanical properties such as Marshall stability, flow, Marshall quotient (MQ), bulk specific gravity, air voids, voids filled with bitumen (VFB) and percent voids in compacted mineral aggregates (VMA) of asphalt mixture has been evaluated. The Marshall tests of the polymer modified asphalt mixture, prepared through dry process, indicated the optimum waste polymer modifier content to be 5% by weight of mix. The waste polymer modified asphalt mix containing 5% WGRTP showed considerable improvement in various mechanical properties of the mix compared to the conventional asphalt mixture. The appropriate amount of the added WGRTP was found to be 5% by weight of aggregate. This percentage results in the maximum level of stability. Keywords—Hot mix asphalt; Waste ground rubber tire powder; Dry process; Marshall test method
Noise Reducing Asphalt Pavements: A Canadian Case Study
Over the last 20 years, many highway jurisdictions have experimented with different asphalts that include blended recycled rubber particles as a way to re-use old tires as well as to monitor the effects of rubber in possibly reducing the aging effects in asphalt pavements. While there have been many claims of noise reduction from different agencies over the years, there was limited conclusive documentation and testing to support the claims. In late 2003, the University of Waterloo's Centre for Pavement and Transportation Technologies (CPATT) and the Regional Municipality of Waterloo embarked on a partnership to first design noise reducing pavement test sections and then secondly to conduct controlled noise testing on four different types of asphalt mixes. The four different surface courses were placed in lengths of 600m. Noise level test results have indicated that the special premium pavement mixes do achieve a reduction in measured noise. The paper will elaborate on the types of materials used, the testing protocol, the measured noise results and the conclusions which will be of use by other municipalities in assessing the merits of using premium surface course asphalts to reduce noise in urban, noise-sensitive environments.
Teaching self-care to delinquent adolescents.
Adolescent delinquency is an ever-increasing societal concern. Certain health problems are concentrated in the delinquent population. Families of delinquent youths often fail to reinforce self-care. Therefore health care providers need to focus on ways to teach delinquent adolescents to care for themselves. This article reviews delinquency and characteristics of juvenile delinquents and their families. A model is presented to guide health care providers to assess delinquent adolescents' abilities to care for themselves and to teach them strategies for self-care.