• Roychand, Rajeev
• Youssf, Osama
• Tahwia, Ahmed M.

Abstract

<p>The high production of carbon dioxide from concrete cement manufacturing and the high utilization of natural resources in concrete has been a concern for research in recent decades. Eco-friendly concrete (Eco-Con) is a type of concrete that uses less energy in its production, utilizes waste materials, produces less carbon dioxide, and is durable. This study assesses the efficiency of the proposed lightweight Eco-Con mixes with 32 MPa compressive strength in repairing different types of concrete structures. Rubber and lightweight expanded clay aggregate (LECA) were used as lightweight materials in the Eco-Con mixes. One Portland cement concrete mix (CC) and three different Eco-Con mixes, namely geopolymer rubber concrete (GR), geopolymer LECA concrete (GL), and rubber-engineered cementitious composite (RECC), were produced and compared. The concrete mixes were utilized as simulated ‘repair’ materials in several types of concrete joints, namely reinforced slab–beam joints (400 × 300 mm L-shape, 500 mm width, and 100 mm thickness) subjected to bending, concrete joints in beams (100 × 100 × 350 mm) subjected to bending, and concrete joints in unconfined and fiber-reinforced polymer (FRP) confined columns (100 mm diameter and 200 mm height) subjected to axial compression. The reinforced slab–beam joint and FRP-confined column joint were tested with two joint angles of 0° and 45°. The results indicated that RECC is an efficient lightweight Eco-Con alternative to Portland cement concrete in repairing concrete structural elements, especially beams and FRP-confined columns, as it increased their strength capacities by 43% and 190%, respectively. At the tested joint angles (0° or 45°), the use of Eco-Con mixes showed relatively lower slab–beam joint strength capacity than that of the CC mix by up to 14%. A joint angle of 45° was better than 0°, as it showed up to 7% better slab–beam joint strength capacity. Using shear connectors in slab–beam joints had adverse effects on concrete cracking and deformability.</p>

Topics

• impedance spectroscopy
• Carbon
• laser emission spectroscopy
• strength
• composite
• cement
• rubber