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M. Tech. Civil Engineering. / Aims to assess the influence of the type of binder on the evolution of the macro texture in asphalt at an early age. The objective are to : 1. To assess the approach and methodology of French asphalt design method. 2. To establish the contributors to the reduction of skid resistance of asphalt. 3. Identify effective methods and develop guidelines for improving the surface drainage of asphalt with the use of tests from the laboratory. Asphaltic materials and factors under investigation include: pervious asphalt, continuously grade asphalt and various asphalt surface characteristics and correlation with the Tri-dim laser.

Thesis (Ph. D.)--University of Nevada, Reno, 2006. / "May, 2006." Includes bibliographical references (leaves 183-187). Online version available on the World Wide Web.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

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

Thesis (M.S.)--West Virginia University, 2005 / Title from document title page. Document formatted into pages; contains vii, 61 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 51).

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains viii, 75 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 61-62).

Low temperature cracking is attributed to tensile stresses induced in an asphalt concrete pavement that develop when the pavement is subjected to a cold temperature. Cracking results in poor ride quality and a reduction in service life of the pavement. Low temperature cracking has been predicted by regression equations, mechanistic approaches and by simulation measurements. The purpose of the study reported herein is to (1) evaluate the Thermal Stress Restrained Specimen Test (TSRST) as an accelerated performance test to simulate low temperature cracking of asphalt concrete mixtures and (2) develop a deterministic and probabilistic model to predict low temperature cracking with TSRST results. Construction histories, cracking observations and temperature data were collected for five test roads in Alaska, Pennsylvania and Finland. A full scale and fully controlled low temperature cracking test program was conducted at the U.S. Army Cold Regions Research and Engineering Laboratory (USACRREL). Specimens were fabricated in the laboratory with original asphalt cements and aggregates from the test roads. In addition, asphalt concrete pavement specimens were cut from the test sections. The TSRST results obtained for these samples were correlated with the field observations. Based on a statistical analysis of the data, the TSRST fracture temperature is associated with the field cracking temperature and crack frequency for the test roads where mixture properties dominated low temperature cracking. It was concluded that the TSRST can be used to simulate low temperature cracking of asphalt concrete mixtures. A deterministic and a probabilistic model were developed to predict crack spacing as a function of time using the TSRST results, pavement thickness and bulk density, pavement restraint conditions and air temperature. The affect of aging on pavement properties was incorporated in the models by predicting the field aging with Long Term Oven Aging (LTOA) treatment in the laboratory. The calculation of the crack spacing is based on the theory that the pavement slab cracks when the pavement temperature reaches the cracking temperature of the mixture and the slab is fully restrained. The deterministic model predicts crack spacing with time whereas the probabilistic model predicts crack spacing and its variation with time and yields the reliability of the design with regard to a minimum acceptable crack spacing criterion defined by road authorities. The models were verified by comparing the predicted crack spacings for the five test roads to the observed crack spacings. The probabilistic model is recommended for use in predicting the low temperature cracking of asphalt concrete mixtures. / Graduation date: 1994

Thermal distress in asphalt concrete pavements is a widespread problem around the world. Thermal cracking can be divided into two modes of distress: low temperature cracking and thermal fatigue cracking. Low temperature cracking results from extremely cold temperatures; thermal fatigue cracking results from daily temperature cycles. Low temperature cracking is attributed to tensile stresses induced in the asphalt concrete pavement as the temperature drops to an extremely low temperature. If the pavement is cooled, tensile stresses develop as a result of the pavement's tendency to contract. The friction between the pavement and the base layer resists the contraction. If the tensile stress equals the strength of the mixture at that temperature, a micro-crack develops at the surface of the pavement. Under repeated temperature cycles, the crack penetrates the full depth and across the asphalt concrete layer. The thermal stress restrained specimen test (TSRST) was identified as an accelerated laboratory test to evaluate the thermal cracking resistance of asphalt concrete mixtures. The TSRST system developed at OSU includes a load system, data control/acquisition system and software, temperature control system, and specimen alignment stand. The overall system is controlled by a personal computer. A TSRST is conducted by cooling an asphalt concrete specimen at a specified rate while monitoring the specimen at constant length. A typical thermally-induced stress curve is divided into two parts: relaxation and non-relaxation. The temperature at which the curve is divided into two parts is termed the transition temperature. The temperature at fracture is termed the fracture temperature and the maximum stress is the fracture strength. An extensive number of TSRSTs over a wide range of conditions were performed to investigate the thermal cracking resistance of asphalt concrete mixtures. The TSRST results provided a very strong indication of low temperature cracking resistance for all mixtures considered. A ranking of mixtures for low temperature cracking resistance based on the TSRST fracture temperature was in excellent agreement with a ranking based on the physical properties of the asphalt cements. It is highly recommended that the TSRST be used in mix evaluation to identify low temperature cracking resistance of asphalt concrete mixtures. The TSRST showed very promising results regarding the effect of all variables which are currently considered to affect the low temperature cracking of mixtures. The variables considered to have significant affect on the low temperature cracking resistance of mixtures in this study include asphalt type, aggregate type, degree of aging, cooling rate, and stress relaxation. / Graduation date: 1994

Testing of asphalt binders and asphalt-aggregate mixtures using dynamic mechanical analysis is becoming popular with improvements in high-speed computers, precision equipment, and computer software. Researchers are trying to describe the behavior of asphalt binders and asphalt-aggregate mixtures in terms of their time- and temperature-dependent linear viscoelastic behavior. The objectives of this thesis were to develop a simplified pneumatic test to perform dynamic mechanical analysis (DMA), to evaluate the performance of the pneumatic and hydraulic test systems using the computer software developed to perform DMA tests, and, to develop a simplified method to evaluate the experimental data obtained from DMA tests on aged asphalt-aggregate mixtures. A simplified pneumatic test system was developed to perform DMA. Computer software was also developed to perform DMA testing on both the simplified pneumatic and hydraulic test systems. DMA was performed on both test systems to compare their performance, and on aged asphalt-aggregate mixtures to evaluate the application of the simplified method. The results from the pneumatic and hydraulic test systems show that there is about a 20 percent difference in the complex modulus, especially at high loading frequencies. This is due to the compressibility of the air used in the pneumatic test system. The compressibility of air is greater at warmer temperatures than at cooler temperatures. Therefore, the application of the pneumatic test system to perform dynamic testing should be limited to low frequencies ( < 2 Hz), low temperatures ( < 25°C), and low load ( < 454 kg (1000 lbs.)) applications unless a modification can be made to increase the pneumatic cylinder's response time to match the hydraulic cylinder's response time. The simplified analysis method developed in this thesis divides the DMA results into four complex modulus and five phase angle parameters. These parameters describe the shapes of the master stiffness and phase angle curves and distinguished between the different asphalt-aggregate mixtures and the aging methods performed on the aged asphalt-aggregate mixtures. The phase angle parameters were reduced into two variables, peak frequency and peak angle, which vary with the aging of each asphalt-aggregate mixture. The peak frequency and peak angle decrease as the aging severity increases and the change of peak frequency and peak angle vary with the asphalt-aggregate mixture and aging treatment. Therefore, the complex modulus parameters and peak frequency and peak angle may be good indicators to describe how a master curve's shape varies with asphalt, aggregate, and aging type. / Graduation date: 1993