Load-Temperature-Shrinkage (LTS) Design of Continuously Reinforced Concrete Pavement
PDF courtesy of the American Concrete Pavement Association’s (ACPA’s) technical resources archives.
With the advent of the continuously reinforced concrete pavement, without joints. the highway engineer has been forced to discard existing design theories and rely largely on experimentation and judgment to attempt to properly design this new type of pavement.
This paper is aimed at presenting a rational and uncomplicated approach to the approximate design of continuously reinforced concrete pavement, considering all of the factors and variables that can be evaluated by means of the engineering tools available. The two major factors to be considered, internal forces developed from restrained pavement volume changes and external forces developed from the traffic loads, are examined, and methods are given whereby each can be evaluated in arriving at an economically safe design. The Load- Temperature-Shrinkage design approach is predicted on the assumption that the concrete should be designed to withstand the external forces developed from traffic loads, and the reinforcing steel should be designed to withstand the internal forces developed from restrained pavement volume changes . It is shown that a pavement thickness of 7 .0 in., with 0.5% interior longitudinal hard grade steel over a subgrade whose modulus of subgrade reaction is 100 psi per in., will be sufficient to carry a 16,000 lb design wheel load. Past experiences are cited to indicate that this design approach is adequate. In addition, the areas for possible modification of the approach by experimentation and research are examined.
Authors: Benjamin F. McCullough and William B. Ledbetter