Life cycle assessment of concrete made with high volume of recycled concrete aggregates and fly ash

Abstract

Since concrete is the most widely used construction material in the world, it is important to improve its environmental performance. A possibility is to use supplementary cementitious materials and recycled aggregates. Therefore, the objective of this work is to compare the environmental impacts (EI) of concrete mixes, which contain different incorporation ratios of fly ash (FA) and recycled concrete aggregates (RCA), with and without Superplasticizer (SP). The Life Cycle Assessment methodology was used for environmental assessment, according to ISO 14040 (2006) and EN 15804 (2012). Contrary to most of the previous studies, this one separately obtained the impact for each life cycle stage in detail (e.g. the impact of raw materials production, transportation, and mixing procedure), and explains the reason behind selecting each dataset. Thus, the results of this study can be used for other case studies. The results show that the EI slightly increased when SP was used. Moreover, the incorporation ratio of fine RCA did not change the results for most of the EI categories. Nevertheless, the EI of most of the categories decreased when coarse NA was fully replaced with coarse RCA. Despite the long transportation distance between the coal power plant and the concrete plant considered in the case study, the EI significantly decreased in most categories with increasing amounts of FA.