Dynamic life cyle carbon assessment of three bamboo bio-concretes in Brazil
Brazil has a vast use of concrete in the construction sector. Having the ability to store carbon for long periods, the development of concretes mixed with bio-based materials can be a promising alternative to ordinary concrete products in the Brazilian building sector, as a measure to reduce the GHG emissions. A bio-concrete with bamboo waste (BB) as main material, mixed with ordinary Portland cement (OPC) and supplementary cementitious materials (SCM), metakaolin (MK) and fly ash (FA), has been developed in laboratory for use as building panels for walls, roofs and floors. This article aims to investigate the effect of storing carbon in three different mixes of bamboo bio-concrete, considering the mass relation of OPC/MK/FA mixed with bamboo waste, additives and water. A cradle to grave life cycle carbon assessment (LCCA) was carried out, considering the production, transportation and end-of-life stages in a Brazilian context, based on data collected in laboratory, literature and the Ecoinvent database. A dynamic LCCA method was applied in order to investigate overall GHG-emissions from compared system and the impact of biogenic carbon emissions and removals over the investigated time-frame. The influence from different transport distances were evaluated through a sensitivity analysis. The bio-concrete with the highest replacement of OPC with MK and FA presented 77% reduction in terms of the sum of instantaneous global warming impact (GWIcum), when compared to no substitution of OPC. When the strength of the bio-concretes (in kg CO2-eq /m²·MPa) was considered, it presented a reduction of 88%. The use of SCMs, especially FA in the cementitious materials relation, also results in great benefits between the three bio-concretes. The use of DLCCA allowed a more consistent and informed assessment of life cycle GHG emissions flows and global warming impact of the bamboo bio-concretes.