Abstract
Lack of environmental and economic assessments parallel to an experimental development of valorization scenarios may offer non sustainable valorization strategies, and vice versa; lack of experimental trials next to the sustainability assessment may offer impractical valorization strategies.The large scale applicati on of sediment based products, which are technically feasible, economically, and environmentally sustainable with the capability to compete with the conventional ones in the market, is still lacking. The integrated life cycle assessment (LCA), life cycle c ost assessment (LCC) and laboratory based experimental assessment were applied to provide insight for early stage decision making on the valorization of the dredged sediments. As a win win collaboration between the civil engineering industry and the port a uthorities, the objective was to find a viable and sustainable solution for the valorization of the dredged sediment in concrete, holding up a certain level of standard concrete performance without compromising in terms of economic and environment. To determine the sensitivity of environmental impacts and the cost of concrete to the number of materials and processes involved in its production, parametric inventories based on a prefixed mix ratio concrete were applied. The consistency in both economic and en vironmental inventories enabled to conduct of reliable comparative assessments between the valorization scenarios. The compressive strength evaluation in the laboratory demonstrated that a maximum rate of sand substitution in concrete up to 40% by predomin antly sandy sediment could sustain the concrete strength class. However, LCA and LCC negated the sustainability of the rate of sand substitution by sediment higher than 20%. Inferred from the results, integrating environmental and economic cost assessments into the laboratory based assessment of the valorization scenarios would determine the threshold for the sustainable rate of incorporation of sediment in valorization scenarios. However, the threshold of sustainable sand substitution by sediment in concre te could be modified through a compromise between the expected mechanical strength and workability of the concrete, the quantity of the superplasticiser as well as sediment transport.