Typescript (photocopy). / Digitized by Kansas Correctional Industries

Typescript (photocopy). / Digitized by Kansas Correctional Industries

In 1987, Congress authorized a 5 year $150 million dollar research program called the Strategic Highway Research Program (SHRP). SHRP was divided into four major areas, including the asphalt research program. The asphalt research program was divided into six major research contracts, one such contract, SHRP-003A was called Performance Related Testing and Measuring of Asphalt Aggregate Interaction and Mixtures. Oregon State University performed the portion of this contract related to the development and validation of accelerated test procedures for aging, low temperature cracking, and moisture sensitivity of asphalt-aggreagte mixtures. This thesis contains five independent papers that discuss elements of the development, validation, and or implementation of these accelerated test procedures. In the first paper, the relationship between field performance and laboratory aging properties of asphalt-aggregate mixtures is discussed, including the relative importance of asphalt binder and aggregate type on the amount of aging experience. Based on this work recommended aging procedures are presented to simulate different environmental conditions and pavement age. The second paper makes use of the large body of resilient modulus data conducted as part of the SHRP research effort to compare data obtain in the diametral and the triaxial mode. It is not possible to give a relationship between triaxial and diametral resilient modulus, without describing specimen geometry and other test conditions. The third paper discusses the effect of aging on the thermal cracking properties of asphalt-aggregate mixtures. The temperature at which aging occurs affects the way cold temperature fracture properties change with time. Low temperatures result in quenching of the aging process, while high temperatures result in continued aging. The fourth paper discusses work conducted in association with the Oregon Department of Transportation to extend the environmental conditioning system (ECS) test procedure for moisture assessment to open graded mixtures. Comparison in the ECS of mixtures with and without anti-strip agents added indicates that they don't always decrease moisture damage potential. The final paper presents a discussion of asphalt chemistry and its relationship to asphalt-aggregate mixture performance. Using the SHRP asphalt model, aging and low temperature performance data collected at Oregon State University is explained. / Graduation date: 1995

Asphalt concrete pavement is subjected to several damaging actions from traffic loads, water (from precipitation and/or groundwater sources), and temperature. The durability of the asphalt-aggregate mixture, its ability to withstand these damaging actions for long periods, is a very important engineering property. While the durability of the asphalt-aggregates mixture depends on several factors such as the mixture's properties, construction methods, traffic loads and environmental conditions, they have to be evaluated to predict their field performance. Based on mixture evaluations, the mixtures that fail the test would have to be modified by additives or by changing the materials. The first objective of this thesis was to evaluate asphalt-aggregate mixtures for water damage using the Environmental Conditioning System (ECS), and rank the asphalt and aggregate types based on water sensitivity. The second objective was to relate the ECS ranking of the asphalt and aggregate types to Oregon State University (OSU) and University of Nottingham, UK (SWK/UN) wheel tracking test results, and to Net Adsorption Test (NAT) results. The third objective was to evaluate open-graded mixtures and rubber modified mixtures for water sensitivity using the ECS. The ECS test results indicate that performance ranking of mixtures by asphalt type or aggregate type alone cannot be made for the ECS test results due to the significant interaction between asphalt and aggregate. Water sensitivity in the ECS is significant for combinations of asphalt and aggregate. The ECS test results have shown that ECS performance ranking after one cycle is not statistically significant and does not correlate with ranking after three cycles. The results show that the ECS test program has similar aggregate rankings to those of the NAT and SWK/UN test program, while good agreement exists between SWK/UN wheel tracking results and the NAT test program results. However, poor agreement exists between the OSU wheel tracking results and those of the other two tests. Poor or very little agreement exists among the wheel tracking test results, ECS, and NAT test results in terms of asphalt type rankings. When considering the comparisons of materials ranking by different test procedures, one must keep in mind that the mechanisms leading to varying "performance" are not the same. The testing reported herein was aimed at measuring water sensitivity, but all the tests do not do so directly. The NAT procedure addresses only the potential for stripping (adhesion) and is not capable of evaluating cohesion loss. The other tests (ECS, OSU and SWK/UN wheel tracking) included all the mechanisms simultaneously, and these provided a gross effect without clearly separating the cause of failure in each case. Open-graded mixtures used by Oregon Department of Transportation (ODOT) performed well in the ECS in terms of water sensitivity. In the ECS evaluation, six mixtures passed the criteria of 75 % established for Indirect Retained Strength (IRS) test by ODOT, and one mixture was marginal. However, only one mixture passed the IRS evaluation, and another mixture was marginal. This confirms that the IRS test is a very severe test and is not suitable for water sensitivity evaluation of open-graded mixtures. Finally, the IRS test evaluation would suggest that these mixtures would fail prematurely after construction, but all of these mixtures have been used in projects which have been in service for more than three years with no visible signs of distress, or failures. / Graduation date: 1994

No description available.

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.

published_or_final_version / Civil Engineering / Master / Master of Philosophy

No description available.

No description available.

No description available.