Pemanfaatan Fly Ash, Eggshell Powder dan Limbah Beton sebagai Substitusi Parsial Material Beton pada High Strength Self Compacting Concrete

Abstract

Concrete is a primary material in infrastructure construction. Innovations in concrete technology have led to the development of High Strength Self-Compacting Concrete (HSSCC), a high-performance concrete with several advantages. However, the high demand for cement in HSSCC production significantly contributes to increased carbon dioxide (CO₂) emissions, which negatively impact the environment. The cement industry is responsible for approximately 5-7% of total global CO₂ emissions, making it essential to find innovative solutions to reduce this impact. This study examines the use of fly ash and eggshell powder as partial cement replacements, as well as concrete waste as coarse aggregate in HSSCC mixtures. Fly ash, which is rich in pozzolanic elements, and eggshell powder, which contains CaO, are expected to enhance the mechanical performance of HSSCC while reducing cement usage. The study uses an experimental method with cement substitution by fly ash at 0%, 5%, 10%, 15%, and 20%, and eggshell powder at 0%, 2%, 4%, 6%, and 8%, along with a 10% substitution of coarse aggregate with concrete waste. Compressive strength tests were conducted at 14 and 28 days. Results show that the FA5E2L10 mix achieved a compressive strength of 54.35 MPa at 28 days, a 2.64% increase compared to normal SCC. However, higher proportions of fly ash and eggshell powder decreased compressive strength and HSSCC performance.