INNOVATIVE APPROACHES TO CONCRETE MIXES: CRUSHED CLINKER BRICK WASTE AS COARSE AGGREGATE

Abstract

The particle size distribution of aggregates plays a crucial role in determining the properties of concrete. Traditionally, sieves have been used to measure aggregate gradation, wherein the percentage of material passing through each sieve is calculated. A well-optimized gradation ensures maximum concrete density, resulting in enhanced compressive strength—the fundamental mechanical property for evaluating concrete quality. Although other concrete parameters like tensile and flexural strength rely on compressive strength, the proportion of aggregates used in concrete (70-80%) underlines their significant influence. Notably, the particle size distribution of aggregates has been found to substantially impact concrete compressive strength, with larger coarse aggregates contributing to increased strength. Due to environmental concerns and the need for sustainable practices, the exploration of alternative materials for coarse aggregates in concrete production has gained traction. Conventional sources like river gravel are ecologically taxing, leading to river subsidence and environmental degradation. In this regard, research has shown the viability of clinker brick waste as a substitute for natural coarse aggregate, yielding concrete with comparable compressive strength to that of conventional crushed stone aggregate. However, there remains a lack of investigation into adjusting the coarse aggregate gradation of clinker brick waste. This study aims to determine the effects of adjusting the aggregate grading of crushed clinker brick waste, utilized as a replacement for coarse aggregate, on various concrete properties. The research assesses slump, density, and compressive strength for concrete mixes targeting strengths of 20 MPa, 25 MPa, 30 MPa, and 35 MPa. Furthermore, the study seeks to explore gradation adjustments that could potentially lead to achieving compressive strengths of up to 40 MPa. The adjustments adhere to the aggregate grading limitations outlined in SNI 7656-2012, classifying them as upper, middle, and lower limits. The investigation encompasses an array of alternative coarse aggregate materials, including paper scraps, plastic scraps, post-consumer glass, expanded polystyrene, crushed rubber, coconut shells, and building debris. This exploration is crucial as it addresses the pressing demand for concrete while promoting sustainable resource management. The benefits of employing alternative materials are manifold, encompassing the reduction of natural coarse aggregate demand, lowered environmental impact in production, potential weight reduction in concrete, and fostering recycling and waste management options.