The economic benefits from use of RAP materials can provide a great boost to the highway industry by freeing funds for additional highway construction, rehabilitation, preservation, and maintenance. In recent years, the incentive to recycle has grown stronger because of concerns about the environment and sustainability. The general public is becoming more aware of the need to conserve natural resources through recycling. The use of RAP can result in sustainable development and cost savings by reducing the amount of virgin materials required in the production of the new asphalt mixture (1).Benefits notwithstanding, excessive amounts of RAP in a mixture can have detrimental effects on pavement performance. Xiao et al. reported that inclusion of 15% RAP resulted in a significant increase in stiffness of the mixture (2). In recent years, as asphalt prices have continued to escalate, a great deal of interest has been focused on the use of higher contents of RAP. Currently, RAP use varies considerably across the United States, but the average RAP content in asphalt mixtures is estimated to be around 15% (3).The belief that pavements constructed with RAP materials are more prone to cracking than virgin mixtures is generally attributed to stiffening and embrittlement effects induced by attempting to combine weathered, age-hardened materials with virgin materials. A careful RAP mixture design achieves proper binder stiffness by considering the aged binder stiffness, virgin binder stiffness, and the proportions of these two binder components present in the final blend. Extensive research has been directed toward characterization of low-temperature properties of pavements that contain RAP (1).The current study explores the effect of RAP amounts on the lowtemperature fracture properties of asphalt mixtures. Study of the lowtemperature fracture properties of HMA with RAP was conducted in the context of five RAP levels and two virgin binder sources. RAP levels of 10%, 20%, 30%, 40%, and 50% were studied with PG 64-22 and PG 58-28 virgin binders. Disk-shaped compact tension [DC(T)] fracture testing was conducted to determine the fracture energy of the mixtures. In addition to the DC(T) test, the Superpave ® indirect tensile (IDT) test, which is widely used in the prediction of low-temperature performance of asphalt mixtures, was conducted on HMA specimens that contained 20% and 40% RAP.A new testing method that was developed on the basis of the acoustic emissions (AE) phenomenon was employed to evaluate the low-temperature behavior of mixtures. The AE phenomenon refers to the generation of a transient, elastic mechanical wave caused by the sudden release of local stresses (strain energy) in a solid medium. When a material is mechanically or thermally stressed to the point Significant increases in the cost of asphalt paving and increased awareness of the need for sustainable infrastructure in recent years have in turn increased the use of recycled asphalt pavement (RAP) in the manufacture of hot-mix asphalt (HMA). The use of RAP...

A prospective study was done to determine the clinical profile of first attacks of acute rheumatic fever in children in North India. Unlike other reports, the clinical profile described here closely resembles the spectrum prevalent in the West. Arthritis, the most common manifestation, was seen in 66.6% of the 102 patients, chorea in 20.7%, and carditis in 33.7%. Carditis was considered mild in 22 patients and severe in 12; a persistent elevation of sleeping pulse rate and mitral regurgitation was noted in each case. Patients with severe carditis also had significant cardiomegaly and apical mid-diastolic murmur. Two patients with severe carditis developed congestive heart failure; one of them had pericarditis as well. Murmur of aortic origin was not noted in this series. One patient with severe carditis died from the disease. Erythema marginatum was noted in two, both of whom had severe carditis. There were two instances of subcutaneous nodules, one with and one without carditis. The close similarity of these results with those in the West is attributed to the prospective design of the study, analysis of first attacks only and survey of a general pediatric population for all manifestations suggestive of the disease.

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A systematic data analytics was employed to determine the relative linkages of stream water quality and environmental health with the land use and hydrologic drivers in the coastal‐urban watersheds of southeast Florida. Power law‐based partial least squares regression models were developed to reliably estimate the linkages by appropriately resolving multicollinearity (Nash‐Sutcliffe efficiency = 0.72–0.95). The analytics indicated Everglades as the external and the largest source of total nitrogen (TN) in the coastal‐urban streams for both wet (June–October) and dry (November–May) seasons. The “external driver” exhibited 1.5–2 times stronger control on stream TN than that of the watershed “land use,” “hydrology,” and the “upstream reach” contributions. In contrast, Everglades appeared to be a minor source of in‐stream total phosphorus (TP), which was predominantly controlled by the internal watershed processes. TP was most strongly linked with the upstream reach concentrations and watershed land uses in the wet and dry seasons, respectively. Despite the predominantly built‐up fraction (74%) of the study area, agricultural land was the most substantial watershed source of in‐stream nutrients. The linkages of algal biomass (Chl a) with the drivers indicated TP as the limiting nutrient. Stream dissolved oxygen was most strongly influenced by the adjacent groundwater depth and watershed land uses, respectively, in the wet and dry seasons. The estimated relative linkages and insights would be useful to identify the management targets and priorities to achieve healthy coastal‐urban stream ecosystems in southeast Florida and around the world.