Development of Waste-Based Alkali-Activated Cement Composites

Area of Science:

• Materials Science
• Environmental Science
• Civil Engineering

Background:

• Global warming and climate change necessitate sustainable alternatives to conventional materials.
• Waste management and recycling remain significant environmental challenges.
• Alkali-activated cements (AACs) offer a promising avenue for addressing these environmental concerns.

Purpose of the Study:

• To develop and optimize waste-based alkali-activated cement (AAC) composites.
• To investigate the use of waste tire rubber as sand replacement and fibrous waste kaolin wool for strength enhancement.
• To evaluate the performance of these AAC composites under various conditions and compare them with traditional binders.

Main Methods:

• Preparation of metakaolin-based AACs with varying percentages of waste tire rubber (5-45 wt %) and surface treatments.
• Incorporation of fibrous waste kaolin wool (0.5-1.5 wt %) to improve mechanical properties.
• Development of blast-furnace-slag-based AAC composites and investigation of storage conditions, specimen size, and cyclic loading effects on compressive strength.

Main Results:

• Surface treatments improved rubber particle wetting within the AAC matrix.
• Waste-based AAC composites achieved a compressive strength of 44.0 MPa, exceeding the 32.5 MPa requirement for clinker saving slag cement.
• Cyclic compressive loading resulted in a slight increase in residual strength, indicating enhanced durability.

Conclusions:

• Waste-based AACs, incorporating tire rubber and kaolin wool, present a viable sustainable alternative to conventional cements.
• The developed AAC composites exhibit excellent mechanical properties and durability, outperforming traditional binders.
• This research contributes to waste valorization and the development of eco-friendly construction materials.