A field trial project was supported by SJVN Limited and funded by the National Technical Textiles Mission (NTTM), Ministry of Textiles, Government of India, under the project “Development of Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) for Building Applications”, awarded to, Department of Civil and Environmental Engineering, IIT Delhi.

Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) is an advanced cementitious material with a minimum compressive strength of 120 MPa and exceptional durability, toughness, and abrasion resistance. These properties result from its optimized mix design, including a low water-to-binder ratio, high binder content that significantly reduces matrix porosity, elimination of coarse aggregates, and the incorporation of high-strength fibers. Its dense microstructure and fiber reinforcement make it particularly suitable for hydraulic structures exposed to severe mechanical and environmental loading.

As part of a field study, UHPFRC was trialed as a repair material for the sluice spillways of the Nathpa Dam on the river Sutlej in Himachal Pradesh. The objective was to assess its feasibility and performance in rehabilitating spillway surfaces subjected to high-velocity water flow, debris, and boulder impact. Parameters such as workability, bond with existing concrete, surface finish, and in-situ performance were evaluated.

Figure 1. UHPFRC trial patch on Sluice spillway at Sluice Bay – 5 (left); and condition of UHPFRC patch after one flow season.

A UHPFRC repair patch was cast in Sluice Bay-5, as shown in Figure 1. The condition of the patch under operational water flow conditions over the one-year period demonstrated exceptional performance. Visual inspections revealed no signs of erosion, abrasion, cracking, or debonding, demonstrating the material’s excellent durability.

These results demonstrate the significant potential of Ultra-High Performance Fiber-Reinforced Concrete (UHPFRC) as a durable and reliable material for the repair and strengthening of hydraulic structures operating under aggressive service conditions. The findings of this study are expected to provide substantial benefits to hydropower operators in India and internationally by offering a robust solution to improve the durability, structural safety, and long-term resilience of sluice spillways and similar hydraulic components. Following the encouraging laboratory and field-scale outcomes, a larger patch trial is currently in progress. Additional full-scale field trial is planned for future implementation to further validate the performance of UHPFRC under real service conditions.