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The carbon embodied in buildings is an important proportion of our emissions and needs to be radically reduced in order to support climate change mitigation. The highest proportion of embodied carbon is usually emitted during the product stage, and within the structural elements. Therefore, reducing the carbon embodied in the structural materials is likely to have a major impact. In most buildings, the majority of embodied carbon comes from steel and concrete. But although there are now hundreds of registered Environmental Product Declarations (EPD) for cements and concretes, there has been very limited independent published information comparing the embodied carbon of different concrete mixes and raw materials. This lack of comparative data limits the potential to make appropriate decisions at early design stages leading to low carbon buildings. The authors have recently conducted a review of verified EPD for concrete mixes and for concrete’s key constituents, including cement, identifying the range of carbon coefficients. This paper provides guidance on making use of the coefficient ranges provided in that research: to support the verification of EPD for concrete and its raw materials; in material selection; in assessing building level embodied carbon; in benchmarking; and in the setting of reduction targets. [ABSTRACT FROM AUTHOR]

With the growing consumption of primary raw materials, the need for recycling of construction and demolition waste (CDW) arises. According to international and national regulations, any waste must be tested for ecotoxicity using a leaching test followed by chemical analysis and a set of aquatic toxicity biotests. Standardized leaching procedures have also been developed for construction materials and products and are used in common practice. On the other hand, studies aimed at direct determination of ecotoxicity are still lacking. Acute toxicity tests with unicellular algae, freshwater crustaceans, and marine bacteria are among the most popular for determining the ecotoxicological potential of recycled aggregates or concrete samples. The article deals with the perspective of semichronic and chronic tests with extended exposure, as well as testing of leachates obtained from leaching events for more than 24 hours. Results of performed experiments were compared and evaluated. From the point of view of sustainability, it is necessary to develop an optimal experimental design for the ecotoxicological evaluation of recycled aggregate and concrete. The conclusion of the paper is the evaluation of possible methods and their combinations. [ABSTRACT FROM AUTHOR]