GeopolyCement

What it does

Cement production emits significant CO₂ but remains essential. GeopolyCement offers a cost-effective alternative using solid alkali activators and agro-industrial waste precursors, with the potential for thermally insulating non-load-bearing uses.

Your inspiration

Rising cement consumption due to rapid urbanization presents a significant challenge. Developing geopolymer cement with a solid alkali activator offers the potential for lightweight foamed concrete with strong thermal insulation properties which can reduce cooling costs by up to 70%, utilizing locally available pozzolans and agro-industrial wastes. The cement’s use of a solid alkali activator was to enable it to be marketed similarly to OPC. The innovation targets Sustainable Development Goals (SDGs) 9, 12, and 13 by promoting sustainable practices, reducing waste, and mitigating climate change impacts.

How it works

Geopolymerization involves reacting aluminosilicates, formed by dissolving silica and alumina, with a strong alkali activator at room temperature. These aluminosilicates can come from natural industrial waste sources like fly ash and rice hull ash. Researchers developed GeopolyCement using agro-industrial waste and pozzolan materials, with a cost-effective calcium-based alkali activator made from limestone and sodium hydroxide. To address high cooling costs, they used the best cement formulation with a foaming agent to produce a lightweight foamed concrete wall panel, reducing construction and cooling costs for houses.

Design process

The study was conceptualized and developed by the Sustainable Resource Research for Construction Technologies Center (SuRER-CT) of MSU-IIT Engineering under the mentorship of Dr. Maria Sheila Ramos. A similar study conducted found that producing geopolymer cement with a lab-grade NaOH-CaCO3 solid alkali activator costs more per bag than OPC, primarily due to CaCO3. A Ca-based solid alkali activator using limestone achieved comparable results to pure CaCO3 activators. Using limestone as a calcium carbonate source showed similar performance to AR-grade CaCO3, making it a viable alternative. Increasing the silica-alumina ratio enhances compressive strength, reduces pH, and increases density. Higher alkali activator percentages improve compressive strength, decrease pH, and reduce geopolymer block density. Foam-modified GeopolyCement mortar proved particularly suitable for non-load-bearing applications. Produced LFC walls had low densities (913.1 kg/m3), low thermal conductivity (0.165 W/mK), flexural strengths (1.64 MPa), and compressive strengths (3.49 MPa), but high water absorption (34.68%) may affect durability in moist environments.

How it is different

GeopolyCement, utilizing locally available raw materials in Mindanao, Philippines, employs a solid alkali activator, unlike conventional liquid ones, allowing it to be packaged and marketed like OPC. OPC is calcined in kilns at ~1100°C, and GeopolyCement is processed at ambient temperature. Moreover, unlike most low-carbon cement, which is OPC-geopolymer hybrids, GeopolyCement is made entirely from agro-industrial wastes and pozzolan materials. This cement formulation is refined by varying the silica-alumina ratio and alkali activator concentration to achieve the best results.

Future plans

Based on the study's findings, recommendations include formulating a low-carbon cement using agro-industrial wastes (e.g., sugarcane bagasse ash, palm oil fuel ash) instead of NaOH, testing additional mechanical properties such as slump and porosity for cement and lightweight foamed concrete wall panels, investigating the interaction between geopolymer cement and foaming agents, identifying suitable foaming agents for geopolymer cement, and exploring blended cement formulations to enhance overall mechanical properties of cement and wall panels.

Awards

The project was one of the 2023 BPI-DOST Innovation Best Innovation Project of the Year Award recipients, recognized for being an outstanding innovation that leverages science and technology to address pressing issues on December 11, 2023.