Field Evaluation of Preformed Membranes

Abstract

Recently, the use of preformed membrane systems has increased as a corrosion preventive technique in reducing chloride intrusion into reinforced concrete bridge decks. However, there is no nondestructive method to evaluate the integrity of in-place preformed membranes. Also, the effectiveness of preformed membranes was not sufficiently addressed. Three different nondestructive methods are evaluated to investigate the integrity of preformed membranes. Ultrasonic pulse velocity is found to be the most feasible. The effectiveness of preformed membranes is investigated by collecting concrete powder samples from bridge decks protected by preformed membranes at three depths. A field evaluation of the preformed membranes’ performance is conducted on fifteen bridge decks in three states: New Hampshire, Maine, and Vermont. The membranes were installed on the decks when new. The bridges’ ages are varied from 2 to 32 years old. They are exposed to different average annual daily traffic, salt application rate, snowfall and so forth. Approximately 45 nondestructive tests were carried out, an average of 14 ground truth cores were obtained, and at least 45 concrete powder samples were analyzed for chloride content per bridge deck. The field evaluation concluded that preformed membranes reduce chloride intrusion if they are installed properly and overlaid with an appropriate layer of hot-mix asphalt, which should be kept in a good service condition. An average life of 40 years is expected for preformed membranes, and an increase of 25 years in bridge deck life is expected.