Durability based life cycle assessment of concrete with supplementary cementitious materials exposed to carbonation

Until now, it remains unclear how "green" concrete compositions with high volumes of supplementary cementitious materials really are, especially when subject to carbonation-induced steel corrosion. This paper results from accelerated carbonation tests for high-volume fly ash (HVFA) and fly ash + silica fume (FA+SF) concrete. They served as input for a probabilistic service life prediction on fib Bulletin 34, and a subsequent life cycle assessment. the inverse effective carbonation resistance of the two concrete types was compared with the one of traditional concrete that is normally used in outdoor, sheltered environments. An attempt was also made to determine the model input parameter that accounts for concrete's curing behaviour using literature data. Other input parameters related to meteorological conditions were accounted for with weather station information. In the end, it was found that the estimated time to carbonation-induced steel depassivation for the less carbonation resistant HVFA and FA+SF concrete still exceeds a predefined life span of 100 years by far. As a consequence, global warming potentials (GWPs) calculated for the required concrete volume per unit of strength and service life indicate that an important reduction in greenhouse gas emissions is possible for both concrete types (GWP -29 to -44 %)