Prof S Suriya Prakash of IIT Hyderabad’s CASTCON Lab and his research group have developed an affordable special ultra-high performance fibre reinforced concrete (UHPFRC) using locally available materials such as cement, fly-ash, river sand, ground granulated blast furnace slag, micro-silica, water, steel fibre, polypropylene fibres, and a high range water reducing agent (HRWRA).
By reducing the amount of cement, fibres, and replacing expensive fine aggregates with cheaper locally available ones through proper gradation, the cost of UHPRC is reduced and made affordable. The mix combines the best characteristics of self-consolidating concrete (SCC), fiber-reinforced concrete (FRC), and high-performance concrete (HPC).
The cost of UHPFRC developed at IIT Hyderabad is about two times cheaper than commercially available proprietary products. UHPFRC, developed at IITH for pre-stressing applications, yields a cube compressive strength of 150 MPa and a direct tensile strength of 8.0 MPa. Several full-scale post-tensioned UHPFRC concrete bridge girders were tested to understand the shear behavior.
According to test results, providing a minimum web shear reinforcement ratio and adequate steel fibre dosage leads to improved serviceability, ultimate strength, and stiffness of bridge girders. The overall cost of UHPFRC girders in bridge applications can be reduced further by providing a minimum web-shear reinforcement of 0.6% and a hybrid fibre volume dosage of approximately 1.0%.
“Strong and durable infrastructure is a must for holistic development of any nation. Developing construction materials with improved strength using locally available raw materials is a creditable stride towards realizing our dream of Aatma Nirbhar Bharat. I am sure such innovation will not only benefit local development in terms of economic and efficient infrastructure but extend its advantage to the infrastructure sector globally,” Prof B S Murty, Director, IITH, said.
Enlisting the uniqueness of the UHPFRC, Prof S Suriya Prakash, CASTCON Lab and Chandrashekhar Lakavath, Research Scholar, Dept of Civil Engg, IITH, said, “The aim is to develop an affordable ultra-high-performance concrete using locally available materials and do a thorough material categorization to understand the behavior of UHPFRC in compression, tension, fracture, and direct shear. Several full-scale bridge girders made of UHPFRC were tested. Our test results have given deeper insights into the shear behavior of pre-stressed bridge girders, which will be used to develop design guidelines for practising engineers. Our research is expected to increase the confidence in using UHPFRC in India for various infrastructure applications”.
