jismart2024077: Optimization of Self-Compacting Concrete Performance and Practical Applications with Varying Ratios of Fly Ash and Molten Slag Fine Aggregates

Abstract

The construction industry faces significant labor shortages due to declining birth rates and an aging population. To improve efficiency, research on self-compacting concrete (SCC) has advanced. Concurrently, efforts to reduce environmental impact have led to exploring industrial by-products like municipal solid waste incineration ash molten slag (MS) as concrete aggregates. This study investigates SCC formulations with varying MS fine aggregate and fly ash (FA) ratios to achieve performance comparable to natural aggregates. Experiments evaluated the effects of MS and FA replacement ratios on SCC’s fresh properties and compressive strength. Concrete mixtures were prepared and tested, with fresh properties assessed through slump flow, J-ring flow, and V-funnel tests, and compressive strength measured at 14 and 28 days.Results showed that MS replacement improved flowability up to 50% but deteriorated at 100% replacement. Higher FA replacement rates enhanced flow characteristics and gap-passing ability. However, higher MS ratios reduced compressive strength, especially in underwater curing. Practical trials showed that SCC with optimized proportions had good workability, though surface defects like air bubbles were noted. Recommendations include adjusting admixture types and amounts, with future work focusing on optimizing flowability with 100% MS replacement while effectively utilizing industrial by- products.