Investigating Load Withstand by L-Shape Concrete Cube, RCC Slab and to Safeguard Reinforcement of RCC Slab in Saltwater Environment Using Cathodic Protection

Abstract

Structures constructed in reinforced cement concrete (RCC) are currently at risk when exposed to saltwater conditions. Eventually, RCC structure fails after the corrosion of reinforcement, reducing strength and its life. The investigation focuses on load-carrying capacity of slab specimen (RCC) and shear strength of L-shape concrete cubes after exposure to saltwater. The concrete of M20 mix was prepared using 53 grade cement to cast L-shape concrete cubes and reinforced slab specimen having 10 mm bar diameter. The size of RCC slab was 300 × 300 × 100 mm and L-shape cubes were prepared after cut of 90 × 150 × 60 mm in regular concrete cube with M-20 mix. After casting and curing of L-Shape cube and slabs, these specimens are exposed to 0.1 M NaCl water for curing. The L-Shape cubes after regular curing gave 12.21 MPa at 7 days and 19.11 MPa at 28 days of shear strength. Furthermore, shear strength increased from 13.42 MPa at 7 days to 21.07 MPa at 28 days after curing in 0.1 M NaCl water for 30 h. A D.C. power supply was used to accelerate the corrosion of steel in the slab at 0.02 mA/mm². Slab specimens tested for 30 h were as follows: slab reinforcement as anode (P1), slab coated with sodium silicate and reinforcement as anode (P2) and slabs reinforcement as cathode (P3) in 0.1 M NaCl water with iron plate as anode. The failure loads of slabs were 41.75 kN for P1, 75.35 kN for P2 and 78.5 kN for P3 type. This study indicates L-shaped cubes after curing in NaCl environment can increase shear strength. In addition, cathodic protection to reinforcement in slab increases load-carrying capacity, ultimately increasing the life of RCC specimen.