Ultra high performance concrete (UHPC): reactive powder concrete, slurry infiltrated fiber concrete and superabsorbent polymer concrete

Ultra high performance concrete refers to a class of advanced and engineered cementitious composite materials that have a superior mechanical and durability properties, compared to conventional concrete. Based on ASTM C1856, ultra high performance concrete should have a compressive strength of around 120 MPa with specifically high durability and toughness properties. Its mixture is usually composed of high quantity of Portland cement and silica fume as the main binding agents, and finely distributed aggregate sizes with a relatively high content of superplasticizer and steel fiber reinforcement. As a result of its very low water-to-binder ratio (~ 0.20) and high admixture usage, ultra high performance concrete has autogenous healing property with proper workability that results in high strength-to-weight ratio, making it suitable for high-rise structures and major infrastructure sections. In this review, a basic description of reactive powder concrete, slurry infiltrated fiber concrete (also known as SIFCON) and superabsorbent polymer concrete, as three major types of ultra high performance concrete are provided. Environmental impact (e.g., life cycle assessment), fresh properties, effects of curing regime, fiber reinforcement and finally mechanical and durability properties are also reviewed and provided. In the end, future projections, undiscovered research areas as well as a comprehensive conclusion on researched properties of ultra high performance concrete is provided. As a result of this review, it is found that, on average, ultra high performance concrete has about 6 times higher compressive strength-to-density ratio, 3 times reduced porosity and 5 times reduced water permeability coefficient, with almost similar thermal resistance when compared to conventional concrete.