Developing sustainable ultra high performance concrete (S-UHPC)

The focus is on engineering high performance green concrete composites to reduce the embodied and operational energy and greenhouse gas emission of concrete buildings in Singapore. After aluminum and steel, the manufacturing of Portland cement is the most energy intensive processes. It requires about 5 GJ of energy per ton and emits 1 ton of CO2 for each ton of cement produced. High performance green concrete composites have the potential to reduce the energy consumption, CO2 emission, and natural resource depletion by replacing up to 50% of cement by waste materials, e.g. ground granulated blast-furnace slag (GGBS) and municipal solid waste incineration fly ash (IFA). Moreover, reducing use of sand and rocks by using recycled concrete as fine and coarse aggregates is considered. This new class of composites needs to fulfill certain performance criteria such as high strength, high ductility, long-term durability, superior crack resistance, and damage tolerance in order to enhance the sustainability of concrete buildings in Singapore. Here, the goals are i) develop a high performance green concrete composite with reduced embodied energy, ii) quantify its mechanical and durability properties, and iii) apply the composite in building systems in order to reduce the operational energy. Some of the accomplishments are summarized below: