Prestressed geopolymer concrete bridge with 100% secundary aggregates

Abstract

In order to reduce the environmental impact of construction, contractors are looking for alternatives to cement based materials. An innovation trajectory has been completed based on the chain collaboration. Based on the chain approach, this project has gone through an innovation trajectory with a duration of 9 months from idea to realization of an in situ post-tensioned geopolymer concrete bridge with aggregates of thermally cleaned tar-containing asphalt granulate. The obtained environmental benefit turned out to be approximately 75%. Two major aspects are presented, process-related and technical related. An answer is given to the question of how an innovative sustainable alternative for cement based mixtures can be developed and actually applied in the practice of an already accepted building project without lead times of decades. Within a lead time of only 9 months, a program has been completed which has led to the realisation of a proven structurally safe in situ prestressed geopolymer concrete bridge. Based on the development of a new geopolymer concrete mixture, primarily aimed at achieving the required strength class and workability, a large experimental campaign has been carried out at Delft University of Technology and other laboratory. Focus was on the structural behaviour of the geopolymer concrete regarding bending, shear and cracking behaviour. This research was carried out on 24 beams of different sizes, reinforcement configurations and mixtures, combined with testing of compressive and tensile strength, young’s modulus, creep behaviour and a multitude of material aspects to prove a 100 year service life of the bridge. The innovation currently applied on the bridge can potentially be widely applied within civil engineering projects.