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The methods employed to determine critical stability constants from the published literature are described and the best approach for estimating stability constants to establish a sufficiently broad and extensive database that substantially defines all of the metal complex systems encountered in the environment is recommended. With these estimated formation constants, it is possible, with modern computer techniques, to calculate the speciation and concentrations of the metal complexes in multicomponent systems containing thousands of ligands and 10 to 100 times that number of metal complex species. The structure-stability relationships developed by other investigators are compared with the methods employed herein. Examples of measured, selected and estimated constants are presented for several metal complexes. The distributions of metal complex species in seawater in the absence and presence of an added complexing pollutant are calculated to illustrate the use of the stability constant database and the adjustment of the constants to the conditions required (i.e., ionic strength) for the system under consideration.

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A study was conducted on a mechanistically based overlay design procedure that incorporates the in situ pavement layer modulus values evaluated by deflection-based nondestructive testing using falling weight deflectometer data. The proposed overlay design procedure addresses the seasonal variation in the state of Idaho and adjusts the modulus values accordingly. The performance of the pavement is calculated in terms of critical strains based on the elastic multilayer theory. The study adopts the Asphalt Institute fatigue and rutting failure criteria to calculate the life of the pavement. Damage analysis is performed based on the past and expected future traffic to calculate the required overlay thickness. The procedure developed has been implemented in an event-driven, user-friendly computer program FLEXOLAY, which runs in the DOS environment. The program was tested and compared with other overlay design methods using pavement sections from the state of Idaho. The overlay thickness determined by FLEXOLAY was found to be close to some of the existing methods and far from others, depending on the existing pavement conditions.

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