Durability and transport properties of SCC incorporating dredged sediments

The use of sediments as supplementary cementitious material is increasing, but very limited information on their effect on durability are available. The aim of this study is to evaluate the durability and transport properties of self-consolidating concrete (SCC) incorporating treated marine sediments (TMS) dredged from Dunkirk harbor. Three SCC mixtures made with 0% (SCC-R), 10% (SCC-1), and 20% (SCC-2) sediments as partial substitution of cement weight were investigated. The mixture proportions were optimized to provide adequate self-consolidating characteristics, including high filling and passing abilities, as well as adequate stability. The optimized SCC mixtures exhibited comparable hardened and microstructural properties at 91 days of age, including compressive strength of 66 +/- 1 MPa, splitting tensile strength of 6 +/- 0.3 MPa, and total porosity of 9 +/- 0.4%. The obtained test results revealed that the incorporation of TMS reduced the critical pore volume (<20 nm) due to their pozzolanic reaction and filling ability. Despite this reduction, increasing TMS content increased permeability and diffusion (e.g., carbonation). Indeed, SCC-1 and SCC-2 showed higher sorptivity of 7.5% and 19.8%, respectively, than that of SCC-R (2.81 E-3 mm(3)/mm(2).s(1/2)). However, SCC-1 showed comparable durability performance to the reference mixture, including chloride penetrability, electrical resistivity, drying shrinkage, external sulfate attack, and alkali-silica. Meanwhile, the use of 20% TMS negatively influenced the chloride penetrability, external sulfate attack, and carbonation velocity. This substitution rate can be considered without mitigating durability of reinforced concrete in moderate exposure conditions. (C) 2021 Elsevier Ltd. All rights reserved.