The American Association of State Highway and Transportation Officials (AASHTO) upgraded the strength of concrete-reinforcing steels to 100 ksi for bridges and other constructions. This helped highway engineers to design with the stronger corrosion-resistant MMFX2 rebar (AASHTO MP18/ASTM A 1035 Grade 100 [690 MPa]).
This engineering improvement will minimize expenses related to replacement of the country¡¦s old infrastructure and end in better-made bridges and roads using lower quantity of steel, mitigating expensive rebar congestion problems and offering cost-effective, corrosion-resistant rebar remedies.
On July 12, 2012 AASHTO upgraded the Load and Resistance Factor Design (LRFD) Bridge Specifications to allow public bridges and other structures to be built with strong reinforcing steel with up to 100 ksi yield. The LRFD Bridge Specifications are the standard used by the state Departments of Transportation (DoTs) to fix bridge design codes.
AASHTO, comprising senior transportation officers from 50 states, the District of Columbia and Puerto Rico, is an international leader in fixing technical standards for highway systems. AASHTO¡¦s validation of the higher-strength steel was founded on the findings and recommendations of the National Cooperative Highway Research Program (NCHRP) Report 679 released in 2011.
As per the Report, using high-strength steel in structures would be advantageous in the concrete construction sector by minimizing member cross-sections and reinforcement quantities, which would result in savings in material, shipping and placement expenses. Lesser reinforcements mean lesser congestion issues, which would result in higher quality of construction. The decision by AASHTO increases the opportunities for the country¡¦s DoTs to optimally utilize the higher-strength MMFX2 rebar to plan and construct structures with 20%ƒ{50% lesser steel and up to 60% lower labor expenses.
MMFX2 rebar was earlier restricted to a strength of 75 ksi in bridge and other structures. Along with better strength MMFX2 rebar also offers better corrosion resistance, resulting in more durable bridges with lesser problems of handling when compared to regular steel bars.
Source: http://www.mmfx.com/