The net-zero and sustainability potential of SCC development, production and flowability in concrete structures

Climate action around the world has shifted to the potential of global warming contribution from the design and construction of infrastructures, especially those in demand for concrete. Concrete production and use have been identified as contributing to >5% of the world’s greenhouse gas (GHG) emissions. The main aim of this research work is to critically study the net-zero and sustainability potentials that the world can leverage on from the development, production and flowability of self-compacting concrete (SCC). Conventional concrete is made of >50% of ordinary cement, which contributes to >7% of the world’s GHG emissions. But in 1988, a fluidized concrete that compacts under its self-weight, known as SCC, was formed and developed to overcome the need for durability, skill and manpower that were dwindling in Japan at the time. This concrete created a pathway for cement to be replaced partially or totally by certain pozzolanic materials that function as viscosity-modifying admixture, high-water reducing agent or microencapsulated phase-change materials in the concrete mix. However, research findings have shown that for these materials to alter the flowability of SCC, there has to be reduced yield stress and moderate viscosity for allowable internal friction based on the Bingham model, and this has to be achieved under the same water–cement ratio. Fortunately, the implication of the use of these admixtures as replacements for cement is that there is a reduced demand for cement production and use in cleaner concrete production and, as such, a reduced CO2 emission associated with this process.