The six papers in this Symposium Publication address many different aspects of mechanistic design, such as environmental stress, improved pavement design methodology, approaches to performance-based specification, characterization of joint sealants for design purposes, characterization of concrete strength based on fracture properties, and others. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP181

This paper develops a finite-deformation viscoelastic material model to characterize the behavior of a silicone-based sealant material. A series of relaxation tests were performed on the test specimens for different levels of age and unit extension. Based on the experimental results, a master relaxation modulus curve is constructed. Unit extension and age effects are incorporated in the master relaxation curve by using the superposition principle. The shift factor equations developed were based on the relationship first suggested by William, Landel and Ferry (WLF Equation) and traditionally used for incorporating temperature effect. The unit extension and age dependence are accounted in the “reduced time”. The material model derived is of the generalized Maxwell (in parallel) type, which is simple and can be easily applied in finite element programs for stress analysis of joint sealants in concrete pavement.

SP-164 (V2) Although bearing and joint systems comprise only a small percentage of the construction cost of highways, buildings, and bridges (1 percent, typically), their importance to the functioning of those structures is vastly greater. For without adequate engineering effort in design of these vital elements to account for the many, sometimes conflicting, requirements of loading and/or movement, the integrity of the entire structure may be compromised. Our increased understanding of seismic activity has made us more aware of the wider area of this activity as the greater demand placed on support and joint systems. This Fourth (quinquennial) World Congress on Joint Sealing and Bearing Systems in Concrete Structures will enhance the general understanding of these systems and introduce entirely new concepts developed to cater to the latest seismic code requirements. As with the first two Congresses, this is V.2 of a two-volume set. V.1 contains 22 papers, plus the abstracts ofpapers presented at the Third Congress.

From shortly before the entry of the U. S. in World War II and to the present, the author has been continuously involved in the design, testing, manufacturing, and observation of the performance of joints of all types, from pavements to bridges, and bearings of all types, from the old rockers to elastomeric, pot, disc, and then to earthquake isolation concepts. Starting out with load transfer devices buried in concrete pavement joints for state highways and airfield pavements to field molded sealants and then compression seals, the design trend in pavements has been from longer 100 ft panels (30 m) to relatively short panels of 15 ft (4.5 m). This has greatly simplified the sealing problem, since the distance changes between joint interfaces of shorter length panels obviously are much less in creep-shrink and thermal volume change. With respect to bridges, the design trend has been reversed, going from relatively short decks of 40 ft (12 m) to longer and longer spans, greatly complicating the sealing problem. It was in this confused design period that the writer worked toward developing sealing and bearing systems for every conceivable type pavement or bridge structure. Some lessons learned during the past 50 or more years are the subject of this paper.

This four-year project was carried out in an aim to conduct a mid- to long-term, large-scale study on selected field-moulded sealants in concrete joints at different hydraulic structures under extremely cold climatic conditions. Other objectives were to specify installation techniques, carry out periodic inspections, evaluate the performance of various types of such sealants that could be of value to all potential users. The project also included a cost effectiveness study. General and specific guidelines were prepared for sealant selection and their installation. Based on these guidelines, different types of sealants, polyurethanes, polysulphides, silicone (1- and 2-component), were selected for the study. They were installed in horizontal, vertical and inclined joints at different locations on five Hydro-Quebec dams, mostly on the crest, and were periodically inspected for their performance. The findings are presented in this paper.