Stainless Steel Extends The Service Life Of Reinforced Concrete Structures

Whenever it is mentioned that the construction or maintenance of reinforced concrete structures can minimize the life cycle cost, many authorities require the use of stainless steel rebars instead of traditional carbon steel bars.

Nickel improves the mechanical properties of stainless steel and helps improve its corrosion resistance.

Commonly used stainless steel rebar alloys

(Nominal chemical composition wt%, balance iron)

When concrete is exposed to chloride-containing environments (such as road salt and sea water), these alloys have long-term corrosion resistance and are now used as highway bridges, ramps and partition walls, parking lots, tunnels, seawalls and Rebar in marine facilities, building foundations and restorations.

The Federal Highway Administration (FHWA) organized an extensive corrosion test and found that when the concrete is contaminated by chloride, the reinforced material can extend the service life of the concrete bridge to 75-100 years. According to a report made in 1998 (FHWA-RD-98-153), it is concluded that stainless steel rebar, such as Type 316, can provide the required service life.

Since the 1980s, nickel-containing stainless steel rebar has been widely used in Europe. In North America, since the mid-1990s, the use of nickel-containing stainless steel bars on highway bridges has been steadily increasing with the construction or extensive repair of large bridges.

Concrete-reinforced stainless steel components: steel bars, U-shaped steel bars, threaded steel bars, steel wire straps and steel couplers.

Installation of stainless steel reinforcement for French Creek Bridge, Chautauqua Company, New York.

Only in the key parts of the structure that are exposed to the corrosive environment, carbon steel rebars are used instead of stainless steel rebars. For bridges, experience has shown that when stainless steel rebar is used, the total project cost increases by 3% or less.

The actual cost increase will depend on the size and complexity of the bridge design. The use of stainless steel reinforcement is expected to extend the service life of the structure to 75-100 years, thereby saving maintenance costs and/or premature replacement of the structure.

Stainless steel bars are produced in accordance with ASTM A955 standards. According to the selected stainless steel grade, yield strength> 75ksi (520MPa) and tensile strength> 100ksi (690MPa) can be obtained. Stainless steel rebar also has excellent toughness, ductility and fatigue resistance. These characteristics are beneficial in earthquake-prone areas and low-temperature applications.

As federal, state, provincial, and local governments require bridges and other important concrete structures to reduce maintenance costs, reduce interruptions, and have a longer service life, it is expected that the use of nickel-containing stainless steel rebar will continue to increase.

Stainless steel rebars, as well as other stainless steel components, such as wire straps, rebar couplers, positioning pins, and welded wire mesh, can all be used to complete the anti-corrosion system.