Optimizing In-Place Density of Asphalt Pavements During Cold Weather Paving in Nebraska

Late season paving is common and often performed in colder temperatures, which is the most challenging environment for attaining optimal in-place density/compaction The in-place density of asphalt pavement greatly affects the lifespan of the pavement. It is also a key factor in preventing major pavement distresses, such as rutting, cracking, stripping (due to water damage) and aging. This research project aims to evaluate and compare the effectiveness of different compaction, delivery, and mix design characteristics to ensure the optimization of in-place asphalt pavement density. To this end, various laydown methods (i.e., Standard Pick-up Machine (SPM) and Material Transfer Vehicle (MTV)) and compaction equipment (i.e., double drum steel rollers, pneumatic rollers, and combination rollers with both steel and pneumatic tires), using both static and vibratory modes were employed. In addition, the effect of different aggregate blend combinations (i.e., using less coarse ledge rock) and asphalt binders (i.e., PG 58V-34, PG 40-40, and PG 52-40) on in-place density were studied. Four test sections were constructed over four separate days of paving, during cold weather conditions. The in- place density was measured using four methods: 1) Conventional/traditional cut roadway cores, 2) Combination of Infrared Continuous Thermal Scanning (ICTS) with conventional/traditional cut roadway cores, 3) Pavement Quality Indicator (PQI), and 4) Rolling Density Meter (RDM) utilizing Ground Penetrating Radar (GPR). The obtained results were compared and contrasted to the current testing, acceptance and construction methods system at Nebraska Department of Transportation (NDOT) and recommendations for future construction specifications and best practices were presented

Asphalt Binder Laboratory Short-Term Aging

The Rolling Thin Film Oven (RTFO) is widely used to simulate asphalt binder short-term aging. However, there is a general interest to improve the current short-term aging protocol especially for reducing the aging time. Besides, there are some doubts about the capability of RTFO in the simulation of aging of highly polymer modified asphalt binders which is mainly due to improper dispersion of such binders in the bottles during rotating and creeping of highly viscous binder out of the bottles during rotation. This work addresses the effect of time, temperature, airflow rate, and weight of asphalt binder on the laboratory short-term aging of asphalt binders and proposes an alternative protocol that can reduce the aging time and resolve some of the current short-term aging protocol shortcomings. In the first part of this study, two asphalt binders, from different sources, were examined in RTFO at different combinations of the above-mentioned test parameters. The high-end continuous performance grading temperature (estimated by dynamic shear rheometer), and carbonyl index (estimated by Fourier transform infrared spectroscopy) were considered as the two responses for quantification and qualification of laboratory aging. The statistical analysis showed that the first order terms of time, temperature, and weight as well as their interactive terms were statistically significant. However, the effect of airflow rate, within the studied range, was insignificant. Based on the findings of the first part of study, an alternative protocol was proposed for the study of short-term aging in a RTFO. One unmodified and three highly modified binders were aged in a RTFO under the current and proposed aging conditions for comparative purposes. According to the obtained rheological (high- and low-end continuous performance grading temperature and viscosity) properties as well as the chemical characteristics (carbonyl index, saturate-aromatic-resin-asphaltene fractions, and oxygen content), it was shown that the proposed laboratory short-term aging protocol not only can reduce the aging time of the conventional protocol, but also that it is applicable to both neat and polymer-modified modern asphalt binders

Divine Hiddenness, Divine Silence

In the present article, he explains why divine silence poses a serious intellectual obstacle to belief in God, and then goes on to consider ways of overcoming that obstacle. After considering several ways in which divine silence might actually be beneficial to human beings, he argues that perhaps silence is nothing more or less than God’s preferred mode of interaction with creatures like us. Perhaps God simply desires communion rather than overt communication with human beings, and perhaps God has provided ways for us to experience God’s presence richly even amidst the silence

Realism in Theology and Metaphysics

The paper will have three sections. In section one I briefly present and respond to Byrne’s argument against theological realism. In section two, I present van Fraassen’s argument against analytic metaphysics and I show how, if sound, it constitutes a reason to reject both metaphysical and theological realism. In section three, I show how van Fraassen can be answered. Obviously what I am doing here falls far short of a full-blown defense of realism in either metaphysics or theology. But the objections raised by van Fraassen and Byrne are tokens of a type of objection that I think is rather widely endorsed among those who are suspicious of these two brands of realism. Thus, responding to those objections constitutes an important first step in the direction of a defense

How Successful is Naturalism?

The question raised by this volume is “How successful is naturalism?” The question presupposes that we already know what naturalism is and what counts as success. But, as anyone familiar with the literature on naturalism knows, both suppositions are suspect. To answer the question, then, we must first say what we mean in this context by both ‘naturalism’ and ‘success’. I’ll start with ‘success’. I will then argue that, by the standard of measurement that I shall identify here, naturalism is an utter failure

Evaluating vitamin premixes for swine

John C. Rea (Department of Animal Husbandry, College of Agriculture)Revised 3/80/10

Managing small hog herds

"One can be successful with a small hog herd. There are, however, some efficiencies realized if the herd size is at least 8 to 10 sows and in most cases this should be a minimum size. Management of a group this size requires about the same amount of time as smaller numbers and the utilization of a boar works fairly well with this number."--First page.John C. Rea (Department of Animal Science)Revised 5/85/5

Care of pigs from farrowing to weaning

The most critical period in the life cycle of a pig is from birth to weaning. On the average, about two pigs per litter are lost during this period. Poor management is the major contributing factor, although the actual cause may be crushing, bleeding from the navel, anemia, starvation or disease. Weaning large litters of thrifty, heavyweight pigs is a key factor for a profitable swine herd. This publication attempts to outline management practices that help keep pigs alive and profits high.John C. Rea (Department of Animal Sciences)Reviewed November 2018 -- websit

Raising hogs in Missouri (1985)

"This guide sheet deals with rather basic data on swine production and will be of most value to the new or beginning producer."--First page.John C. Rea (Department of Animal Science, College of Agriculture)Revised 5/85/5

Care of pigs from farrowing to weaning

"From birth to weaning is the most critical period in the life cycle of a pig. On the average, about two pigs per litter are lost during this period. Poor management is the major contributing factor even though the actual cause may be crushing, bleeding from the navel, anemia, starvation, or disease. Weaning large litters of thirty heavyweight pigs is a key factor for a profitable swine herd. This Guide attempts to outline management practices that help keep pigs alive and profits high."--First page.John C. Rea (Department of Animal Science, College of Agriculture)Revised 5/85/6