Comparative Studies on Compressive Strength of Concrete Using Dredged Marine Sand

Abstract

The depletion of source of natural aggregate necessitates to discover its alternative. Sand is important constituent of concrete which is generally obtained from the quar- ries or alluvial river beds. More extraction of sand from the river bed has become harmful for environment due to depletion of sand layer. Therefore, it becomes neces- sary to nd out the alternative which can serve as long term replacement of sand. To counteract this problem, research is going on investigating the suitability of dredged marine sand, o -shore sand and dune sand as replacement for river and. In this study, the e cacy of marine sand is investigated as a replacement for natural river sand. To examine the performance of concrete with dredged marine sand in terms of com- pressive strength, concrete cubes are cast by varying grade of concrete (M25 and M40) and % content of river sand replaced by DMS (0% and 100%). Exposure condition is assumed as very severe similar to marine environment. Since study is carried out for pumpable concrete, 25% y-ash is added as a mineral admixture in both the grades of concrete. Aim of this study is to scrutinize the effect of replacement of river sand with marine sand on compressive strength of concrete. For durability studies plain concrete cubes are placed in sulfate exposure and chloride exposure. Similarly, RCC slab panels are cast by varying two parameters, compressive strength of concrete (M30 and M40) and % content of river sand replaced by DMS (0% and 100%). Cores are extracted from these panels. Water permeability test, water ab- sorption test, carbonation test and Rapid Chloride Penetration Test (RCPT) are conducted on these cores. The project mainly concentrates on the use of Dredged marine sand (DMS) as a Fine aggregate during casting of concrete and evaluating the mechanical properties like compressive strength & Durability properties. Sulfate, Chloride exposure, Water permeability and RCPT tests for plain concrete cubes are done in present investi- gation. Standard size concrete cubes are cast as per IS provisions. Change in the appearance and change in mass after exposures in all chemicals are observed and studied for durability properties. Also, the non-destructive testing is performed for the concrete specimens. The results related to mechanical and durability properties for all concrete mixes have suggested adequate performance of concrete made with dredged marine sand as compared to the concrete with natural river sand. Mechanical properties of concrete made with dredged marine sand indicate higher results for concrete made with 100% dredged marine sand as compared to that of concrete made with 100% replacement of river sand. Thus investigation suggests successful use of dredged marine sand in concrete as a Fine aggregate in construction activities. Furthermore investigation is to be done related to the chloride resistance of concrete with dredged marine sand.