<title>Early-age durability assessment of cast-in-place RC bridge deck</title>

Abstract

A novel method for evaluating concrete permeability at an early age is being developed for use in performance-related specifications where the material durability is specified as a performance parameter. In developing the method, the fundamental relationship between ultrasonic pulse velocity (UPV) and permeability of a porous medium is derived. An experimental relationship between UPV and concrete permeability is also established which strongly correlates with its theoretical counterpart. This experimental relationship is developed from UPV and permeability tests conducted on specimens made from a series of concrete grades. The experimental relation utilized the data collected from specimens made from a total of 20 bridge deck normal concrete mixes corresponding to five w/c (water-cement ratio) groups of 0.35, 0.40, 0.45, 0.50 and 0.55. The implementation procedure developed is the application of the 'paste efficiency' principle. In implementing 'paste efficiency' principle during the casting of a bridge deck, standard specimens are prepared in the field and cured in the laboratory. UPV measurements are obtained at an early age both from the deck and the standard specimens. The decrease in UPV from standard specimens indicates paste quality loss (PQL) and is proportional to the increase in permeability of deck concrete.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.