Geopolymer Concrete, FRP Create Long-Lasting Structures

Brief 

Australian researchers teamed with the City of Greater Geelong Council in Victoria and Australian Engineering Solutions to replace portland cement-based concrete with geopolymer concrete and steel rebar with fiber-reinforced polymer rebar to create a high durability concrete with greater tensile strength that shows no signs of degradation after more than two years.

Insight

Geopolymer concrete and fiber-reinforced polymer rebar can be the perfect match for sustainability in structural applications.

Steel and concrete have a love-hate relationship. Steel brings tensile strength to concrete, making it stronger for structural applications. Alas, concrete lets water seep into the relationship and corrode the hope for a lasting union. To fix this marriage, Dr. Ruth (Westheimer) has been replaced by Dr. Mahbube Subhani, Ph.D., of Deakin University in Victoria, Australia.

Subhani’s team is focused on sustainability of construction materials, which by necessity must show direct long-term economic benefits. Alternative materials become more economical when you move the needle from cradle to gate (materials to construction) to cradle to grave (full structure life cycle). Let’s take a look at their work.

SOLVING THE CORROSION ISSUE

When properly manufactured and placed, ready mix concrete can last for centuries. However, there are countless examples of bridges and other load-bearing, cast-in-place concrete infrastructure requiring significant maintenance after much shorter time spans. This is often due to corroding steel rebar, especially in saltwater or freeze-thaw environments.

The difficult question is how to economically produce load-bearing structures that last longer, let alone reduce the carbon footprint. Subhani’s team, in concert with the City of Greater Geelong Council in Victoria and Australian Engineering (Austeng) Solutions Pty. Ltd., charted a promising approach. They replaced portland cement-based concrete with geopolymer concrete and then replaced steel rebar with fiber-reinforced polymer (FRP) rebar.