The primary objective of this study is to investigate the suitability of utilizing dune sand as a paving construction material in hot desert-like areas of the world, where regions of sand dunes exist. The high availability, low cost, and excellent physical properties of the current surplus of elemental sulfur and the benefits given to asphaltic binders by sulfur raises the possibility of using sulfur in asphalt mixes to produce stable mixtures with locally obtainable dune sand. Characterization of various sulfur-asphalt-dune sand mixtures for highway construction were made. The materials used in this investigation were elemental sulfur, AR-4000 (60-70 pen.) asphalt, and dune sand from Yuma, Arizona. The main variables include (a)proportion of sulfur and asphalt in the binder, (b)amount of binder in the mixture, (c)curing temperature, (d)test temperature, and (e)mixing techniques. The various mixtures were prepared by the one-wet mixing cycle technique. Similar dune sand mixtures with asphalt only were evaluated for comparison purposes. The different mixes were evaluated by the Marshall method, tensile strength tests (double punch), compression tests (standard and immersion), flexural tests (standard), dynamic modulus tests (double punch), and microscopic examinations of sulfur-asphalt binders and sulfur-asphalt-dune sand mixtures (thin sections). Preliminary characterizations of the various mixes were made on the basis of their Marshall stability, flow, density, and air void contents. Other engineering properties such as tensile strength, compressive strength, modulus of rupture, dynamic modulus, and microscopic studies were determined for selected mixes. The results consistently indicated that the sulfur-asphalt-dune sand mixes exhibited superior engineering characteristics and performance as compared to similar mixes without sulfur. The overall conclusion drawn from this study is that the dune sand which is not normally accepted for use as aggregate in asphaltic mixtures, can be used with the utilization of sulfur-asphalt binder systems to produce paving mixtures with compatible or better engineering properties in comparison to conventional asphaltic concretes.

Submitted to The Arizona Highway Department Phoenix, Arizona for Research Project - Arizona HPR-1-14(167) / The research has been directed toward obtaining information on some of the physical properties of various asphalt- rubber (A-R) mixes as related to waterproof membrane applications. In particular, three rubber particle size distributions and three asphalt-rubber spread quantities were investigated. Laboratory testing utilized for physical property determination included thin film permeability, water absorption (ASTM D570-72), Water Vapor Transmission (ASTM E96-72, procedure BW), ductility (ASTM D113-74), Tensile-Toughness, viscosity and slope stability. The results of the study showed that the A-R as an integral membrane is relatively impermeable. The addition of the rubber does not affect the permeability of an otherwise homogeneous asphalt film. Physical property values of asphalt that are increased when rubber is added include water absorption, slope stability, toughness and viscosity. Those that exhibit lower physical property values include ductility and slope/flow characteristics. Installation of experimental field plots provided additional positive information on the waterproofing characteristics of the A-R and also helped develop field procedures on A-R application to a prepared subgrade.

Pavements are a major part of the infrastructure in the United States. Moisture damage of these pavements is a significant problem. To predict and prevent this kind of moisture damage a great deal of research has been performed on this issue in past. This study validates an analytical approach based on surface energy aimed at assessing moisture damage. Two types of bitumen and three aggregates are evaluated in the study. The two types of bitumen represent very different chemical extremes and the three aggregates (a limestone, siliceous gravel, and granite) represent a considerable range in mineralogy. Moisture damage was monitered as a change in dynamic modulus with load cycles. The analysis demonstrates the need to consider mixture compliance as well as bond energy in order to predict moisture damage. Mixtures with the two types of bitumen and each aggregate with and without hydrated lime were evaluated. The hydrated lime substantially improved the resistance of the mixture to moisture damage.

No description available.

Today, a large quantity of waste is generated from the replacement of residential and commercial roofs. Many of the roofs being upgraded with previously constructed from asphalt shingles. Recycled Asphalt Shingles (RAS) contain nearly 30% of asphalt cement by mass, which can be a useful additive to asphalt pavements. In addition, shingles can offer significant potential savings through recycling and recovery as a construction material in flexible pavement. Currently, one and a half million tons of roofing shingle waste is generated each year in Canada related to the replacement of residential and commercial roofs and 90% of this valuable material is sent to landfills. If engineered properly, the addition of RAS into Hot Mix Asphalt (HMA) can provide significant benefits. The University of Waterloo’s Centre for Pavement and Transportation Technology (CPATT) is committed to working with public and private sector partners to develop sustainable technologies for the pavement industry. Using RAS in HMA can lead to economical, environmental and social benefits. Examples of which are reduced waste going to landfills and a reduction in the quantity of virgin material required. This research has involved the Ontario Centres of Excellence (OCE) and Miller Paving Limited. It was conducted to evaluate the performance of HMA containing RAS in both field and laboratory tests. A varying percentage of RAS was added to six common Ontario surface and binder layer of asphalt mixes. The intent was to determine if RAS could be added to improve performance and provide longer term cost savings. Laboratory testing was performed to evaluate the mix behavior. The elastic properties, fatigue life and resistance to thermal cracking were all evaluated at the CPATT laboratory. The characteristics of the mixes were evaluated by carrying out Dynamic Modulus, Resilient Modulus, Flexural Fatigue and Thermal Stress Restrained Specimen Test (TSRST) tests following American Association of State Highway and Transportation Officials (AASHTO) and American Society for Testing and Materials (ASTM) standards. Field test sections were constructed from HMA containing RAS to monitor the pavement behavior under natural environmental and traffic loading conditions. Evaluation of the field sites was performed using a Portable Falling Weight Deflectometer (PFWD) and carrying out distress surveys following the Ministry of Transportation Ontario (MTO) guidelines. The results to date show the sections performing very well with minimal to no distress developing. The results of the laboratory testing and field performance evaluations have shown encouraging results for the future use of RAS in HMA. If RAS can properly be engineered into HMA it can be a useful additive in both the surface and binder layers of the flexible pavement structure. Ultimately, the use of RAS in HMA can provide both an environmentally friendly and cost effective solution to the Ontario paving industry.

Warm mix asphalt (WMA) technology has now been successfully used in Ontario for a few years. This shift in usage relates to extensions in construction season, reduced emissions, larger compaction windows, and potential fuel savings. This research between Miller Paving Ltd. and the Centre for Pavement and Transportation Technology attempts to better quantify the difference in hot mix asphalt (HMA) and WMA. The object of this study was three-fold. The first part of the research was to examine the strength characteristics of HMA and WMA as a function of storage time. The purpose of this evaluation was to quantify indirect tensile strength (ITS) and moisture susceptibility of HMA and WMA over time. The second objective involved evaluating the performance characteristics of HMA and WMA. Resilient modulus and dynamic modulus testing were completed on plant-produced HMA and WMA material, which was used to determine long-term performance properties of both mixes. The third and final objective of this study was an economic analysis performed to determine the difference in cost for construction and maintenance for the HMA and WMA pavements. This was completed to determine if the cost of the warm mix technology used in the production of the WMA was offset by fuel savings at the plant. The findings of the research included: • HMA and WMA had statistically equivalent air voids over a four-week storage period. • Dry and wet ITS results for the WMA increased over a four-week storage period while the HMA specimens did not show this same increase. • WMA material had slightly better workability than the HMA material although the values were statistically equivalent. • WMA mix had higher resilient modulus values than the HMA mix. • Dynamic modulus testing showed that at high temperatures, WMA showed to be slightly more susceptible to rutting than the HMA mix, and at lower temperatures, the HMA showed to be slightly more susceptible to fatigue cracking than the WMA mix. • The MEPDG showed that both the HMA and WMA pavements were deemed to be structurally adequate. • An economic analysis of the HMA and WMA pavements compared a life cycle cost analysis over a 20-year design life which included all costs associated with construction, maintenance, and rehabilitation of both the HMA and WMA and showed that the HMA was slightly more cost effective than the WMA. • A field trial was performed by Miller Paving Limited on Highway 62 in Madoc, Ontario showed that the WMA material was more effective at maintaining the temperature of the asphalt mixture during long hauling distances. • Overall the WMA exhibited the same performance properties as the HMA.

Thesis (M.S.)--University of Nevada, Reno, 2007. / "May, 2007." Includes bibliographical references (leaves 70-71). Online version available on the World Wide Web.

Thesis (M.S.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (Ph.D.) - Carleton University, 2002. / Includes bibliographical references (p. 189-195). Also available in electronic format on the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 117-121). Also available via the Internet.