Mechanical properties and elevated temperature performance of structural lightweight geopolymer concrete

Area of Science:

• Materials Science
• Civil Engineering
• Sustainable Construction

Background:

• Ambient-cured structural lightweight geopolymer concrete (LWGPC) performance at high temperatures is under-researched, limiting practical use.
• Current geopolymer concrete studies often require thermal or steam curing, hindering field applicability.

Purpose of the Study:

• To optimize ambient-curing parameters for developing LWGPC suitable for laboratory hardening.
• To evaluate the high-temperature behavior (150-750 °C) of optimized LWGPC compared to normal-weight geopolymer concrete (NWGPC).
• To assess the environmental impact through Life Cycle Assessment (LCA).

Main Methods:

• Optimization of LWGPC production parameters: precursor dosage, NaOH molarity, alkali-to-binder ratio, aggregate gradation, silica fume content, and superplasticizer demand.
• Selection of two optimized LWGPC mixtures based on fresh and hardened properties for thermal testing.
• Comparative thermal analysis against NWGPC and Life Cycle Assessment (LCA) for CO2 emissions and energy consumption.

Main Results:

• Optimized LWGPC mixtures were successfully developed using ambient curing.
• LWGPCs with pumice aggregate demonstrated superior property retention and structural integrity compared to NWGPC at elevated temperatures up to 750 °C.
• Life Cycle Assessment indicated lower embodied CO2 emissions and energy consumption for pumice-based LWGPC compared to Portland cement-based concrete.

Conclusions:

• Pumice-based, ambient-cured geopolymer concretes offer enhanced thermal resilience.
• These LWGPCs present a sustainable alternative with reduced environmental impact compared to conventional concrete.
• The developed LWGPC shows significant potential for field implementation due to its reliable high-temperature performance and ambient curing capability.