Using locally available materials like cement, fly-ash, river sand, ground granulated blast furnace slag, micro-silica, water, steel fiber, polypropylene fibers and high range water reducing agent (HRWRA), a team of researchers at IIT Hyderabad (IIT-H) has successfully developed an affordable special ultra-high performance fiber reinforced concrete (UHPFRC).
The cost of UHPFRC developed at IIT-H is about two times cheaper than commercially available proprietary products, a release said on Friday.
Prof. S. Suriya Prakash, CASTCON Lab, Department of Civil Engineering and his research group at IIT-H, brought down costs by reducing the quantity of cement, fibers and replacing costly fine aggregates with cheaper locally available ones through proper gradation.
The composition combines the best features of self-consolidating concrete (SCC), fiber-reinforced concrete (FRC) and high-performance concrete (HPC).
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 behaviour.
Test results show that providing a minimum web shear reinforcement ratio and adequate steel fiber dosage leads to better serviceability, ultimate strength, and stiffness of bridge girders.
The overall cost of UHPFRC girders in bridge applications can be further reduced by providing the minimum web-shear reinforcement of 0.6 per cent and a hybrid fiber volume dosage of about 1 per cent.
Prof S. Suriya Prakash, CASTCON Lab, IIT-H, said: “Several full-scale bridge girders made of UHPFRC were tested. Our test results have given deeper insights into the shear behaviour 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.”
Prof B.S. Murty, Director, IITH, said: “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 realising our dream of AatmaNirbhar Bharat. I am sure such innovation will not only benefit local development in terms of economic & efficient infrastructure but extend its advantage to the infrastructure sector globally.”