Title: Concrete Maintenance
Author(s): L. F. Harza and G. G. Roby
Publication: Journal Proceedings
Appears on pages(s): 571-577
Points out that maintenance and repairs to concrete structures which are suffering from disintegration of the concrete are often, if not usually, con-sidered as a contracting problem rather than an engineering problem. Suggests that such problems should be carefully studied by engineers to insure that the repair work will prove satisfactory. The repairs made in 1932 to the spillway of a dam constructed in 1922 are described. The soillway and the gate pier concrete was apparently placed without due care in mixing, pits, placing, etc., stripping, gravel, and disintegarated badly in IO year. A new concrete facing about 2 ft 8 i’n. thick was placed on the downstream side of the spillway, and the gate piers were replaced completely. The new spillway facing was reinforced by l-in. round deformed bars on I2 in. centers both ways, 6 in. in from the surface. The new facing was anchored by tn. round dowels embedded 40 in. into the original structure. Bond between the old and new concrete was obtained by applying a plaster coat of 3 mortar on the old concrete. The mortar was thrown against the old concrete and then vigorously slapped by hand to cause the neat cement to penetrate into the old concrete. The repairs have proved satisfactory in all respects.