Research on preparation method and flexural properties of low carbon dredged material fine-grained concrete with calcined dredged material powder

Under China’s “dual carbon” goals and “transportation powerhouse” strategy, massive dredged material is generated from waterway maintenance projects but suffers from low resource utilization, while conventional dredged concrete faces prominent high-carbon issues due to heavy cement consumption. Existing studies have extensively explored basic properties of dredged sand concrete, yet systematic research focusing on the performance of low-carbon dredged-material concrete with calcined DMP under different composite cementitious systems, as well as dedicated flexural strength ff prediction models, remains absent. To fill this gap, this study prepares low carbon dredged material fine-grained concrete (LCDMC) using dredged sand as aggregate and DMP as partial cement replacement, and investigates the effects of DMP dosage and composite cementitious formulation on ff and strength contribution rate. A modified ff prediction model incorporating DMP dosage and curing period is established and validated, and carbon emissions are quantified. Results show that 10% DMP coupled with 20% slag achieves the best 28 d ff of 8.24 MPa. The proposed model outperforms the traditional ACI model in accuracy, and the optimal mix reduces cradle-to-gate carbon emissions by 27.1% through cement replacement, and by 28.3% under the project-specific on-site dredged-sand boundary (vs. ordinary Portland concrete using river sand transported 60 km).