Experimental Investigation on GPC with Partial Replacement of Coarse Aggregates by Granite Chips

This paper investigates the properties of concrete on replacement of its content using ground granulated blast furnace slag (GGBS) as a binder and granite chips (GC) as coarse aggregates (CA). GC is rich in Si and Al and is the by-product of granite slabs. The study investigates the performance of GPC on the replacement of CA with different percentage levels of GC. The study aims to find a sustainable solution for their disposal. This experimental investigation was performed to evaluate the strength properties of concrete. GGBS is the binder, and a combination of sodium hydroxide and sodium silicate solution acts as an alkaline activator. The molarity of NaOH is taken as 12 M. The ratio of sodium silicate to sodium hydroxide solution is taken as 2.5. The ratio of an alkaline solution to binder is taken as 0.35 to prepare the M40-grade concrete. Specimens were tested for 3 and 7 days at room temperature. Test results revealed that the strength of GPC increases with the replacement of CA with GC. It was observed that on replacement of 50% of CA with GC there is an 11.5% increase in early strength (3 days) of GPC. Similarly, for 75% and 100% strength observed was 27% and 32.3%. However, after seven days, the increase in strength is marginal. Similar observations can be made in the flexural strength of the concrete also. SEM images were studied for the Elemental analysis of surfaces (EDS). A cost comparison observed that the GPC of M40 grade with GC is 3% economical when it is replaced by 100% granite chips. Considering the carbon footprint of normal concrete production, it is inferred that the use of GPC is a sustainable alternative and replacing CA with GC will also reduce the cost of GPC with increased mechanical properties.