Retrofitting Reinforced Concrete Beams with Eco-friendly Ferrocement Mortar

This study investigated the effect of using eco-friendly materials such as silica fume, crumb rubber, and waste plastic fiber in ferrocement mortar. It is also compared with their performance against traditional mortals. The effect of using two types of reinforcement, welded wire mesh and glass fiber mesh, in ferrocement to retrofit beams with full or U-shape wrapping was also studied.

The experimental program consists of casting ten reinforced concrete beams with dimensions of 150×250×1800 mm. Two beams served as reference beams. The other eight beams were preloaded to 70% of the failure load, then retrofitted using ferrocement with two layers of mesh and a thickness of 25 mm.

The results showed that the highest increase in ultimate load was 13.6% for the beam retrofitted using traditional mortar and reinforced with welded wire mesh in full wrapping. For eco-friendly mortar, the highest increase was 7.7% for the beam retrofitted with welded wire mesh and 6.2% with glass fiber mesh, both in U-shaped wrapping. Beams retrofitted using eco-friendly mortar exhibited higher ductility than those with traditional mortar, by 3.6% with welded wire mesh and 5.4% with glass fiber mesh in full wrapping. However, their stiffness was lower compared to traditional mortar.

The increase in ultimate load for welded wire mesh is due to higher tensile strength compared to glass fiber mesh. Eco-friendly mortar causes an increase in ductility and reduces stiffness due to weak bonding between materials, resulting in more deformation.

Ferrocement is an effective method for retrofitting RC beams due to its availability, low cost, and effectiveness in improving beam behavior.