Alkali-Activated Slag as Sustainable Binder for Pervious Concrete and Structural Plaster: A Feasibility Study

Area of Science:

• Materials Science
• Sustainable Construction
• Geochemistry

Background:

• Traditional Portland cement production has a significant carbon footprint.
• Developing low-environmental-impact binders is crucial for sustainable construction.
• Alkali-activated slag (AAS) binders present a promising alternative.

Purpose of the Study:

• Investigate the feasibility of AAS binders for structural plaster and pervious concrete.
• Develop an M10-grade AAS plaster for masonry building retrofitting.
• Evaluate the use of tunnel muck as recycled aggregate in AAS pervious concrete.

Main Methods:

• Formulated and tested AAS plaster for workability, applicability, and compressive strength.
• Incorporated shrinkage-reducing admixtures to mitigate plaster shrinkage.
• Developed AAS pervious concrete using tunnel muck aggregate, assessing strength and permeability.
• Analyzed the relationship between aggregate size and properties of no-fines concrete.
• Compared the Global Warming Potential (GWP) and Gross Energy Requirement (GER) of AAS materials with conventional ones.

Main Results:

• AAS plaster achieved a 28-day compressive strength of 10.8 MPa and reduced shrinkage by up to 45%.
• AAS pervious concrete with tunnel muck aggregate reached compressive strengths up to 20 MPa and permeability rates of 500-3000 mm/min.
• Confirmed the influence of aggregate size on no-fines concrete properties.
• AAS materials demonstrated a 50-75% reduction in GWP and a 10-30% reduction in GER compared to conventional materials.

Conclusions:

• Alkali-activated slag binders are viable for structural plaster and pervious concrete applications.
• Recycled tunnel muck can be effectively used as aggregate in AAS pervious concrete.
• AAS-based materials offer significant environmental benefits, reducing GWP and GER compared to traditional cementitious materials.