Strength Characteristics of M30 Concrete using Blended Fine Sand of Coastal area and River Sand as Fine Aggregate

Developing countries are facing an increasing demand for concrete to support infrastructure, a key driver of economic development. However, fine aggregate, a crucial component of concrete, is becoming scarce due to government restrictions on river sand mining to mitigate the environmental impact. Researchers have explored various alternatives, including the use of sea sand or dredged sea sand as fine aggregate. This study investigates the use of fine sand from coastal areas as an alternative to fine aggregate, thereby making concrete sustainable. Blends of river sand and fine sand in varying proportions are tested for their suitability as fine aggregate based on gradation and chemical analysis. Mix designs for M30 concrete are prepared using a combination of river sand and blended fine sand, which conforms to Zone III gradation, as the fine aggregate, alongwith ordinary portland cement (OPC) and portland slag cement (PSC). Compressive and split tensile strength test results showed that M30 concrete with OPC using 50% fine sand and 50% river sand blend, alongwith conventional stone aggregate, met the required strength parameters. A concrete blend of 50% fine sand and 50% river sand, alongwith PSC, reached its characteristic strength at 28 days but achieved only 98% of the target mean strength.