INVESTIGATION ON STRUCTURAL BEHAVIOURS OF RCC BEAMS STRENGTHENED WITH CFRP AND FERROCEMENT

Abstract

Despite the long service life of RCC structures, external factors can cause deterioration, resulting in a loss of load-bearing capacity and the formation of significant visible cracks. As a result, maintaining the safety and stability of reinforced concrete structures necessitates repair and strengthening. Because retrofitting can be a cost-effective way to replace RCC structural elements, the main purpose of this experiment is to proof that CFRP and Ferrocement strengthening techniques are effective strengthening option. For this purpose, 12 RCC beams of 700 X 150 X 160 mm, using M20 grade of concrete and Fe415 steel bars, were cast and load tested in both flexural and shear failure modes , with one point loading test for flexural failure mode and two points loading test for shear failure mode. The structural behaviour of reinforced concrete beams strengthened using Carbon Fibre Reinforced Polymer (CFRP) and Ferrocement laminates has been investigated and compared to control beams and also, the load carrying capacity predictions of RCC beams before and after strengthening was carried as per ACI-318M-11,ACI-440-2R-08, ACI 549 for Control, CFRP strengthened and ferrocement strengthened beams respectively. As a result, it is found that beams strengthened with CFRP for flexure has increased their load-carrying capacity by 20.28% at the final stage comparing to control beams, whereas the deflection and crack width was reduced by 18.75% and 31.5% respectively. However flexural load-carrying capacity was also increased up to 9.5%at the ultimate stage for the beams strengthened with Ferrocement compared to control beams, similarly the deflection and the crack width was also reduced by 6.25% and 16.85% respectively . Meanwhile, beams reinforced with CFRP for shear has also increased their load-carrying capacity by16.3% at the ultimate stage. but, deflection and crack width was reduced by 20% and 49% respectively .On the other hand, beams strengthened with Ferrocement for shear the load-carrying capacity has increased by 8.2% at ultimate stage comparing to control beams ,as well deflection and crack width was reduced by 13.33% and 38.3% respectively . The experimental investigation reveals that the strengthened beams with CFRP are better than ferrocement in both and flexural, shear behaviours as well as deflection and crack width control. This investigation also proofs the effectiveness of both CFRP and ferrocement for improving the overall structural behaviours of RC beams.