STRUCTURAL APPLICATIONS USING ULTRA HIGH-STRENGTH FIBER REINFORCED CONCRETE

Considerable progress has recently been achieved in strength and ductility of concretes. The use of superplasticizers and large amounts of silica fume led to densified cementitious matrices and improved adherence to the fiber reinforcement. These two properties are obtained with Compact Reinforced Composite (CRC) developed at Aalborg Portland and closely studied during a 3-year EC. The investigations reported in this paper cover the application of ultra high strength-fiber reinforced concrete to enhance performance of beams, columns and beam to column connections. Mechanical tests were performed on full-scale structural elements. Beams of 13 m in length, columns of 2.9 m in compression with and without eccentricity of the load, and beam to column connections were tested. In all cases, concrete strengths of more than 150 MPa were achieved. Due to CRC's high compacity and its extreme resistance to the penetration of aggressive elements, the CRC cover to the reinforcement was typically reduced from 30 mm to at least 12 mm. It has been shown that a reduction in concrete cover to the reinforcement is compatible with the requirements of structural applications. The tests carried out have shown the possibility of using ultra-high strength concrete for large-scale structural concrete elements and opens new fields of applications. This contributes to saving raw materials, weight and volume and to improving ductility and durability.