Lifecycle Assessment and Multi-Parameter Optimization of Lightweight Cement Mortar with Nano Additives

Area of Science:

• Materials Science
• Civil Engineering
• Sustainable Development

Background:

• Growing demand for sustainable building materials necessitates evaluating beyond engineering properties.
• Lifecycle assessment and multi-criteria optimization are crucial for novel construction materials.
• Fly ash cenospheres and nano additives offer potential for enhancing cementitious composites.

Purpose of the Study:

• To develop and optimize a green, sustainable, lightweight cement mortar using fly ash cenospheres.
• To investigate the synergistic effects of multi-walled carbon nanotubes and nano silica on mechanical properties.
• To assess the environmental and economic viability through lifecycle assessment and cost analysis.

Main Methods:

• Utilized cenospheres as fine aggregates for lightweight cement mortar.
• Incorporated multi-walled carbon nanotubes (MWCNTs) and nano silica (NS) at varying percentages.
• Conducted flexural and compressive strength tests.
• Performed cradle-to-gate lifecycle assessment and direct cost analysis.
• Employed the TOPSIS method for multi-criteria optimization.

Main Results:

• Nano additives synergistically improved the mechanical properties of the mortars.
• Cenosphere utilization reduced environmental impacts and enhanced economic feasibility.
• MWCNTs increased material costs, suggesting a balance with nano silica.
• The optimal mix identified was 0.05% MWCNTs and 0.02% nano silica.

Conclusions:

• The developed lightweight cement mortar offers a sustainable alternative for the construction industry.
• Binary addition of nano additives, particularly nano silica, can mitigate cost increases from MWCNTs.
• Multi-criteria optimization successfully identified a high-performing and sustainable mortar mix.