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

Asphalt-Portland Cement Concrete Composite (APCCC) is a hot-mix asphalt with air voids in the range of 25 to 30 percent which is later filled with resin modified cement grout. The resin modified cement grout consists of portland cement, fly ash, sand, water, and prosalvia (PL7) additive. The objective of the research was primarily to evaluate the asphalt-portland cement concrete composite under laboratory conditions. Asphalt-portland cement concrete composite specimens were prepared using the Marshall procedure. The physical and durability properties of APCCC were evaluated at one, three, seven, and 28 days of curing. The evaluated physical properties include stability, indirect tensile strength, compressive strength, and resilient modulus, while the evaluated durability properties include water sensitivity, freeze-thaw and chloride intrusion resistance. Specimens were also tested for different moist curing levels to evaluate the optimum moist curing period. Three moist curing periods were evaluated: no-moist curing, one-day moist curing, and three-day moist curing. The test results were compared with those of SM-5 hot-mix asphalt (a Virginia surface mix); results of chloride intrusion resistance were compared with those of portland cement concrete specimens exposed to similar conditions. The study concluded that asphalt-portland cement concrete composite is an effective alternative technique to be used as an overlay on bridge decks especially with preformed membranes, due to its high strength, durability, and lower air void content. / Master of Science