Turan Özturan

TENSILE BEHAVIOR OF POST-INSTALLED ANCHORS IN PLAIN AND STEEL FIBER-REINFORCED NORMAL- AND HIGH-STRENGTH CONCRETES

The use of anchors for attachments of structural members to concrete come in two general categories: cast-in-place and post-installed. The use of post-installed anchors allows greater flexibility in planning, design, and strengthening of concrete structures. This article reports on a study of the load-deflection behavior of adhesive and grouted anchors embedded in both plain and steel fiber-reinforced normal- and high-strength concretes. The authors tested 12 and 16 mm-diameter adhesive anchors at embedment depths ranging from 40 to 160 mm. Grouted anchors of 16 mm diameter were tested at 80, 120, and 160 mm embedment depths. A total of 57 anchors (39 adhesive and 18 grouted anchors) were tested under monotonic tension loading. Test results showed that pullout capacities of the anchors were not significantly affected by the addition of steel fibers into the concrete. Anchor tests ending with concrete failure resulted in severe damage on plain concrete. With the addition of steel fibers, however, the damage on concrete was significantly reduced. The ultimate capacity of the anchors generally increased with increasing concrete strength. The authors note that current design methods (ACI 349-85 and concrete capacity design [CCD]) overpredicted the pullout capacity as governed by concrete failure.

Effect of Curing on Durability of Fly Ash Concrete

This paper describes the durability of fly ash concrete subjected to various curing conditions. Sorptivity, chloride-ion penetration, and resistance to deicing-salt scaling were tested for concretes containing 0, 15, 30, and 45% Class C fly ash by weight of cement. Specimens were tested at 28 and 56 days after being subjected to 3 different curing conditions. It was noted that increasing the fly ash content decreased the sorptivity, chloride-ion penetration, and deicing-salt scaling of concretes with the exception that they were increased for the specimens that were not properly cured. Highest durability performance was observed for concrete specimens subjected to hot water curing. Moist cured specimens had the next highest durability.