Life Cycle Assessment of alkali activated materials: preliminary investigation for pavement applications

The capital investment in the US for construction and maintenance of the infrastructure road network is $150 billion/year. Investments in OECD countries will likely stabilize, while other countries will face an exponential growth of investments for infrastructures driven by the development of metropolitan cities. Continued “business-as-usual” practice for portland and asphalt cement concrete pavement construction ignores the increasing warning calls for the identification of more sustainable and less energy intensive paving materials. Alkali activated materials concrete (AAM) have been studied with growing interest during the last three decades. AAM show promising results in terms of mechanical performance, while also having a global warming potential impact 30-80% less than that of portland cement concrete. The global warming potential of AAM is closely dependent on the: 1) activating solution used to activate the raw material and 2) origin of the raw material. Specifically, the impact of the transport for both of these components is ~ 10% of its global warming potential. Hence, to increase the adoption of AAM for pavements, it is fundamental to analyze the existing literature to clarify the link between environmental impact and mechanical performance, identifying opportunities for applications that are tailored to the local availability of raw material.