Microstructural and Impact Resistance Optimization of Concrete Composites with Waste-Based Aggregate Substitutions

Area of Science:

• Materials Science
• Civil Engineering
• Environmental Science

Background:

• Increasing demand for durable infrastructure requires advanced concrete composites.
• Conventional concrete's brittleness and low energy absorption limit its use in protective structures.
• The construction industry's significant CO2 emissions necessitate sustainable material solutions.

Purpose of the Study:

• To evaluate the impact of replacing natural aggregates with waste-derived materials (SBR rubber, copper slag, polypropylene, glass) on concrete properties.
• To assess the mechanical properties and impact resistance of these novel concrete composites.
• To quantify the environmental benefits, specifically CO2 emissions, through a life cycle assessment (LCA).

Main Methods:

• Partial replacement of natural aggregates with SBR rubber granulate, copper slag, polypropylene, and glass granulate.
• Mechanical testing including compressive strength.
• Impact resistance experiments to analyze failure modes and energy dissipation.
• Microscopy (SEM, stereoscopic) to characterize additives and interfacial bonding.
• Life Cycle Assessment (LCA) to estimate CO2 emissions.

Main Results:

• Recycled components did not compromise essential compressive strength criteria.
• Significant improvements in impact resistance, including altered failure modes and enhanced kinetic energy dissipation, were observed.
• Microscopy revealed insights into cement paste-aggregate interactions with the waste materials.

Conclusions:

• Judicious use of selected waste materials can enhance concrete's mechanical and impact performance.
• Incorporating these recycled constituents reduces reliance on virgin resources and lowers CO2 emissions.
• This approach supports the principles of a circular economy in the construction sector.