Evaluation of Early Strength Requirement of Concrete for Slab Replacement Using Accelerated Pavement Testing

Abstract

Five full-size concrete replacement slabs were constructed and tested by a heavy vehicle simulator (HVS) at 6 h after concrete placement to study the early strength requirement of concrete for slab replacement. Stress analyses of the test slabs under the HVS loads were performed using the FEACONS (finite element analysis of concrete slabs) program. Changes in the concrete properties with time and the actual temperature differentials in the concrete slab were incorporated in the analysis. The maximum induced stress is a function of the applied load and pavement design, and also a function of the elastic modulus of the concrete, temperature differential in the slab, moisture, creep, shrinkage and the coefficient of thermal expansion of the concrete. This requires that the anticipated maximum stress be properly determined. Having a flexural strength of greater than the anticipated maximum induced stress at the time the slab is open to traffic will ensure that the concrete will not fail prematurely at early age. A conceptual approach on how to determine the required property for concrete for slab replacement at different environmental conditions is presented in this paper.