Title: Sulfate Resistance of Roller Compacted Concrete

Author(s): Nader Ghafoori and Zhiwang Zhang

Publication: Materials Journal

Volume: 95

Issue: 4

Appears on pages(s): 347-355

Keywords: compressive strength; expansion; fly ash; roller-compacted concrete; sodium sulfate; sulfate attack;

DOI: 10.14359/377

Date: 7/1/1998

Abstract:
The failure load is several times greater than the wheel loads of heavy trucks and, thus, it is accepted that the ultimate load-carrying capacity of bridge decks are safe enough to resist wheel loads in service state. However, many bridge decks in Korea have failed locally due to repeated and moving traffic loading. Therefore, the bridge decks, in regards to the fatigue problem, should be designed to ensure adequate safety and durability during design life. Previous researchers who investigated the fatigue behavior of bridge decks were concerned mainly with the following topics: reinforcement ratio; reinforcing methods (orthotropic and isotropic); and loading methods (fixed pulsating loads, stepwise moving pulsating loads, and simulated moving wheel-load). These tests were conducted at the center or centerline of the bridge deck panels, which were bounded by girders and diaphragms, and, thus, the effects of the loading positions were not considered. For this reason, the fatigue life of a bridge deck is usually expressed as a function of the punching shear strength at the center of the deck panel. If the center of the deck panel is not a critical point for fatigue loading, additional fatigue tests would be needed to investigate the position of the bridge deck, which is more critical for fatigue loading than the center of the panel. This paper is aimed at investigating the variations in punching shear strength and fatigue strength of composite bridge decks at various positions. Test results are compared with previous test results, especially results obtained by Hewitt. The experimental tests were conducted on one-third-scale model deck slabs, which were modeled to simulate a typical composite bridge deck. Punching tests were conducted at six positions, and three pulsating test positions were selected among the punching test positions. These loading positions were carefully selected based on the relative magnitude of the sectional forces (compressive in-plane forces and shear forces) in the slab, which were obtained by three-dimensional finite element analysis.