ANALYSIS OF MECHANICAL PROPERTIES OF CONCRETE PARTIALLY REPLACED BY QUARRY DUST AND GROUND GRANULATED BLAST FURNACE SLAG

Abstract

The research examined how natural sand replacement with sandstone quarry dust affected the mechanical properties and durability of M30 grade concrete. The study assessed different replacement levels which involved replacing natural sand with sandstone quarry dust at 10% 20% 30% 40% and 50% replacement levels. The researchers used BIS 10262 (2009) mix design guidelines to create concrete mixtures which they then tested for fresh properties through slump tests. The researchers conducted tests on hardened concrete to measure its density and compressive strength and splitting tensile strength and water absorption and sorptivity and rapid chloride permeability at three testing intervals of 7 days and 28 days and 90 days. The research team used X-ray diffraction (XRD) and scanning electron microscopy (SEM) to study microstructural features which included phase composition and morphological characteristics. The study results showed that quarry dust added to concrete increased its density and compressive strength which reached optimal performance levels at 40% sand replacement. The researchers found that splitting tensile strength reached its highest value at 40% substitution which demonstrated that quarry dust contributes to concrete strength improvement.

The durability tests showed that higher replacement percentages resulted in decreased water absorption and decreased sorptivity and decreased chloride permeability, which showed better environmental protection against degradation. The SEM analysis showed that quarry dust's smaller angular particles filled the concrete's empty spaces and created better concrete microstructure, which resulted in stronger cement pasteto-aggregate bonding. The XRD results showed that all replacement levels produced identical cement hydration products, which confirmed that quarry dust physically contributed to the concrete structure while it did not chemically react during hydration. The study found that replacing natural sand with up to 40% quarry dust produced sustainable concrete mixes, which improved both mechanical strength and durability of the material.