Study on the physical, mechanical and mineralogical properties of dredged marine sand as a partial replacement for fine aggregate in concrete

Abstract

Dredged Marine sand are the excess sediment deposits removed periodically from the beds of artificially constructed ports and harbors to maintain the design depth and to facilitate waterway. Due to this phenomenon, large quantum of dredged marine sand pile near the estuary by routine dredging activities which has initiated several environmental and public issues. To alleviate the issues, in the recent, several studies have been conducted for the effective utilization of dredged marine sand as construction material. Moreover, the dredged marine sand sediments have considerable economic and environmental advantages when employed as a substitute material for natural fine aggregates in concrete production. This study emphasis on the physical, mechanical and mineralogical characteristics of concrete replaced with dredged marine sand as fine aggregate. For the study, the dredged marine sand samples were collected from the dredging site of the Ariyankuppam estuary close to the artificially created fishing harbor of the Puducherry coast. The collected samples were used in concrete after screening with preliminary treatment to remove shells, organic substances, and other contaminants. The investigation conducted on the mineralogical properties of dredged marine sand showed that silicon oxides (quartz), calcite (CaCo3), calcium sulfate (CaSo4), sodium sulfate (Na2So4), and other minerals were present. The presence of calcite, calcium improves the durability and strength of the concrete while, silicon oxides acts as a filler material. The dredged marine sand's physical characteristics indicated that the samples are finer and matches with the properties of conventional materials. The chemical characteristics evidenced the presence of heavy metals like iron (Fe), lead (Pb), and zinc (Zn), which are found in chemical properties, serve to accelerate the reaction in concrete and improve its qualities. For a comparative study, both treated and untreated dredged marine sand partially and completely replaced with M−sand were used in concrete for the investigation. From the analysis of the test results pertaining to the mechanical properties of dredged marine sand concrete which performed better than conventional concrete, a cost-effective way to improve the characteristics of concrete both at its fresh and hardened state.