Evaluation and enhancement of curing efficiency of joints in concrete pavements

Abstract

Optimum curing is essential in controlling durability performance of concrete. Absorption has been used as an indicator for quantifying the concrete durability, while the reliability of current absorption test methods with respect to curing efficiency and geometry of joints in concrete pavements is still unexplored. Curing efficiency of joints at early-age may be compromised due to uncontrolled evaporation resulting from saw-cutting processes. Therefore, providing an optimum curing and monitoring its efficiency with a real-time continuous measure is appealing. Also, a quantitative model of unsaturated flow ingress with respect to curing applications may provide a holistic understanding to predict the concrete durability. Therefore, this thesis aimed at assessing the effect of different curing compound applications on concrete pavements and overfilling joints with curing compound immediately after saw-cutting on improving the quality of concrete microstructure. Also, an effort was made to develop a customized test protocol for determining the absorption capacity of joints in concrete pavements. In addition, this thesis explored the correlation between the dielectric response of real-time sensor embedded in concrete with hydration development of paste as well as setting time. Moreover, this thesis investigated and developed an analytical model based on Katz-Thompson relationship to determine the absorption capacity of joints in concrete pavements according to an absorption test customized to the joint geometry of pavements. This thesis program involved experiments on laboratory specimens as well as cores extracted from field pavement and laboratory slabs. Absorption, rapid chloride penetrability, maturity, thermogravimetry, mercury intrusion porosimetry, and scanning electron microscopy tests were conducted. The results indicated applying a thorough coat and overfilling the joints with curing compound immediately after saw-cutting significantly improved concrete microstructure. Also, the proposed absorption protocol was efficient, robust and reliable in reflecting concrete microstructure of field pavement sections. Moreover, the dielectric response of concrete is strongly correlated to the hardening threshold and strength/hydration development of concrete, and thus it may be potentially used as a field indicator. Finally, the unsaturated flow model reliably simulated fluid transport at joint locations in concrete with accurate predictions relative to experimental results.