Study on the influence of curing conditions in production of precast elements of ultra-high performance fiber reinforced concrete

Abstract

The development of concrete mixes based on packing of particles with reduced size by the use of reactive powder (such as silica fume and ground quartz), superplasticizer, high reactivity cement and steel fibers allowed the formulation of concretes capable of reaching strengths significantly higher than those reached by the traditional concrete. The Ultra-High Performance Concrete Fiber-Reinforced Concrete (UHPFRC) enable the construction of lighter and thinner structures, with low maintenance cost and longer life cycle, beside the infinity of possible uses: bridge decks, viaducts and pedestrian bridges, beams, columns, piles, precast tunnels, hull vessel, reservoir elements etc. The purpose of this research is to develop a study on the influence of thermal and pressurized curing conditions on the strength of precast elements. The use of thermal curing is already common in precast elements to accelerate the production cycle. With UHPFRC it becomes even more advantageous, because it can increase final strength; on the other hand, the usage of pressure is still underexplored, but viable on industrial conditions and capable of meaningful contributions. Starting from a known and previously tested mix and a slab in reduced scale, an experimental analysis on the influence of pre-curing time, curing temperature and pressure on the mechanical properties and performance of the element will be carried out. Based on the performance observed in the experiments, the potential use of the curing techniques will be evaluated.