Life cycle greenhouse gas emissions of hemp-lime concrete wall constructions in Serbia: The impact of carbon sequestration, transport, waste production and end of life biogenic carbon emission

The construction industry contributes to climate change through significant greenhouse gas emissions. Utilising sustainable building materials with low embodied environmental impacts and low greenhouse gas emissions is key to future sustainable development. Bio-based materials, such as hemp-lime concrete, possess environmental advantages as they make use of a renewable raw material and can sequester CO2 from the atmosphere. Through the use of life cycle assessment methodology the study analyses the greenhouse gas emissions associated with the life cycle of a hemp-lime concrete wall and examines the effects of variations that can arise during the life cycle of the material. Sensitivity analyses were used to examine the effects of varying the hemp shiv sequestration factor, binder carbonation factor, gate to site transport distances and raw material construction waste on greenhouse gas emissions, culminating in the creation of three primary emission scenarios (average, pessimistic and optimistic). It was found that the examined variables can have a large impact on greenhouse gas emissions and the environmental perception of the material, as the optimistic life cycle scenario had a negative global warming potential (-9.696kgCO2eq.), while the pessimistic scenario had a positive global warming potential (10.165kgCO2eq.). Additionally alternative end of life scenarios were developed to examine the effects of varying hemp shiv degradability at the end of life stage, demonstrating the potentially large impacts a high factor of degradable organic carbon can have on life cycle greenhouse gas emissions.