Concrete is one of the most widely used and versatile construction materials in modern infrastructure development. However, improper construction practices, inadequate compaction, and the use of unsuitable ingredients can adversely affect its performance and durability. Insufficient compaction is one of the major causes of defects in concrete, often resulting in the formation of honeycombs and voids. These problems can be effectively minimized through the use of Self-Compacting Concrete (SCC), which does not require external vibration or mechanical compaction. The use of SCC also reduces the labour and time associated with conventional compaction. SCC is considered a special type of concrete that has the ability to flow and compact under its own weight, filling the formwork and passing around reinforcement without the need for vibration, while maintaining resistance to bleeding and segregation.

Rapid industrialization has resulted in the generation of significant quantities of industrial by-products and waste materials. These wastes originate from various manufacturing and industrial processes and possess different physical and chemical characteristics. Improper disposal of such materials can cause serious environmental and health-related problems. Therefore, their safe management and beneficial utilization are essential for achieving sustainable development. Conventional cement production requires considerable quantities of natural resources and is also associated with significant carbon dioxide (CO₂) emissions. Consequently, industrial by-products possessing pozzolanic or cementitious properties can be effectively incorporated into concrete as partial replacements for cement. Furthermore, the increasing scarcity of natural river sand and conventional aggregates has created a major challenge for the construction industry. Excessive extraction of river sand has caused environmental degradation, and restrictions on river sand mining have therefore been implemented in several regions.

The present study investigates the potential utilization of industrial by-products, particularly Ground Granulated Blast Furnace Slag (GGBS), Fly Ash (FA), and Manufactured Sand (M-sand), as alternative materials in the production of Self-Compacting Concrete. The primary objective of the investigation was to develop SCC by partially replacing cement with GGBS and natural fine aggregate with M-sand. A total of thirty different concrete mix proportions were developed. Cement was replaced with GGBS at levels of 0%, 10%, 20%, 30%, 40%, and 50% by weight, while natural fine aggregate was replaced with M-sand at 0%, 20%, 40%, and 60% by weight. In addition, fly ash was incorporated at 20% of the total powder volume in each concrete mixture.

The fresh properties of SCC were initially investigated in terms of flowability, passing ability, and viscosity. These characteristics were assessed through standard tests, including the slump flow test, T₅₀ slump flow test, V-funnel test, L-box test, and U-box test. The hardened properties were subsequently evaluated by determining the compressive strength and split tensile strength of the concrete mixtures containing different proportions of GGBS and M-sand.

The experimental investigation indicates that the incorporation of GGBS can contribute to the formation of a denser concrete matrix and improve the strength and durability characteristics of SCC. The combined utilization of GGBS and M-sand also promotes the development of hydration products, particularly calcium silicate hydrate (C-S-H), which contributes to improved mechanical performance. The findings demonstrate that GGBS and M-sand can be effectively used as partial substitutes for cement and natural fine aggregate, respectively, in Self-Compacting Concrete. Their utilization can reduce the consumption of natural resources, minimize industrial waste disposal, and decrease the environmental impact associated with cement production. Thus, incorporating GGBS and M-sand in SCC represents a promising approach toward the development of economical, environmentally friendly, and sustainable concrete.

 

Keyword: industrial waste, pozzolonic nature, Self-Compacting Concrete, Honeycomb formations, bleeding