This research was conducted to study more realistic explanations of how variables are created and dealt with during hot mix asphalt (HMA) paving construction.--P. ii.

Previous research indicated that density, gradation, and asphalt content change due to segregation. A rolling nuclear gage capable of measuring both density and hydrogen count was evaluated for its ability to detect and measure both density and asphalt content. Eight projects (four recently constructed pavements and four during construction) were used to evaluate this instrument. Longitudinal density profiles were obtained for each project at transverse quarter points across the lane. Additional testing included infrared thermography and traditional destructive testing of cores.

"Infrared thermography (IRT) is an effective non-destructive testing method in the field of concrete and asphalt pavements inspection. IRT is used to have an initial evaluation of the surface and near surface of pavements in a very time effective manner compared to other types of nondestructive testing (NDT) methods. Different aspects of IRT and its use to assess surface and subsurface defects in different types of pavements are being studied and evaluated in our research group. The effect of the depth of delamination inside concrete pavement on IRT technique is being studied. It is suggested by our group that there is a correlation between the surface crack profile on the asphalt pavements and its temperature, which will help us to evaluate pavement performance condition. Finally, a full laboratory study is being conducted to experimentally quantify the effects of weather conditions and surface coating on the ability of IRT to assess surface cracks on both asphalt and concrete pavements."--Boise State University ScholarWorks.

Even though moisture sensitivity of Hot Mix Asphalt (HMA) mixtures has been recognized as a major form of distress in asphalt concrete pavements since the advent of asphalt paving technology, the mechanism of this problem has not been clearly identified until now. However, it has been agreed that it can be characterized by the loss of adhesive bond between the asphalt binder and the aggregate or by a softening of the cohesive bonds within the asphalt binder, both of which are due to the action of loading under traffic in the presence of moisture. The evaluation of Hot Mix Asphalt moisture sensitivity has been divided into two categories: visual inspection test and mechanical test. However, most of them have been developed in pre-Superpave mix design. This research was conducted to develop a new test protocol which can overcome the problems of the current procedures and to evaluate the possibility of using the Nottingham Asphalt Tester (NAT) in the resulting procedure.

With national trade barriers falling, causing the expansion of the com petitive global market, the question of quality control has become an essential issue for the 1990s. The time where the promise was to replace a product if it does not work seems to have passed; what is more impor tant now is not so much a reduction in what is going wrong but an increase of what is going right the first time (Feigenbaum 1990). This new trend is sometimes referred to as total quality. Among the many advantages ofthis zero-defect manufacturing policy, we can enumerate (Laurin 1990): superior marketability of wholly de pendable products, enormous gain in productivity, elimination of waste ful cost in replacing poor quality work and retrofitting rejected products from the field. Although total quality is a relatively new and attractive concept for mass products such as cars, consumer electronics and per sonal computers, in many fields, mainly aerospace and military, it has been the rule for years because of security reasons.

New technologies have enabled the pavement engineer to develop a better picture of the pavement structure. Two of these new technologies are ground-penetrating radar and infrared thermography. Each of these techniques allows the pavement engineer to nondestructively evaluate subsurface defects within and under the pavement. Infrared thermography is now widely used to determine the location of delaminations within the pavement.