Concrete Bridge Decks: Deterioration and Repair, Protective Coatings, and Admixtures Kyhpr 64-2,-3 and -4; Hpr 1(1)

摘要

The report is an historical account of damage sustained by new and old concrete bridge decks. An effort has been made to evaluate all bridge decks in Kentucky which (1) have had special admixtures in the concrete, (2) have been repaired by use of varied materials, and (3) have had various protective coatings applied to them. While no conclusive discoveries have been made, several worthwhile, generalized ideas have evolved. Some of the recommendations which were made for concrete bridge decks are as follows: A minimum of 2 inches of concrete should be maintained above reinforcement. Full-width screeding and floating machines should be required. Concreting should not be started until it has been established that there is sufficient equipment for rapid delivery and placement of concrete. Excess concrete should be maintained in front of screed. Slump and air-content tests should be performed on each batch of concrete. Batches not meeting specifications should be rejected. Effort should be made to prevent workmen from walking in fresh concrete. Low areas should be over-filled with fresh concrete. Excessive vibration and over-finishing should be discouraged, and tempering prohibited. Curing compounds should be applied immediately after water-sheen has disappeared. Cleaning and rinsing of decks after heavy application of deicing chemicals and sand should be standard practice. Boiled linseed oil should be applied at 2 to 4-year intervals. In making repairs, remove all unsound concrete and perimeter of such areas sawed to eliminate 'feather-edging.' Air-entrained concrete is recommended for patches, 2 inches in depth or greater. (Author)