Effect of Foam Formulation on Magnesium Sulfate Cement Performance

Area of Science:

• Materials Science
• Construction Engineering
• Chemical Engineering

Background:

• Magnesium sulfate-based foam concrete is a promising lightweight material.
• Controlling pore structure is key to optimizing its mechanical and thermal properties.
• Foam stabilizers like xanthan gum (XG) and foaming agents (GX-7) influence pore evolution.

Purpose of the Study:

• To regulate the density of magnesium sulfate-based foam concrete.
• To investigate the impact of foam dosage and stabilizer ratio on pore structure.
• To elucidate the relationship between microstructural changes, mechanical performance, and thermal insulation.

Main Methods:

• Adjusting foam dosage and the ratio of xanthan gum (XG) to GX-7.
• Evaluating pore structure evolution using bleeding rate tests and scanning electron microscopy (SEM).
• Measuring compressive strength and thermal conductivity.

Main Results:

• Increased foam dosage led to higher pore density and reduced average pore diameter in ultra-lightweight foam concrete.
• Bulk density and compressive strength decreased with increasing foam addition.
• Optimal pore architecture (uniform morphology, well-defined structure) achieved at 100% foam dosage (MgO mass), yielding a density of 136.3 kg/m³ and thermal conductivity of 0.081 W/(m·K).
• Excessive foaming (multiplier > 125%) increased bubble rupture frequency.

Conclusions:

• Foam dosage and stabilizer ratio are critical for controlling the microstructural properties of magnesium sulfate foam concrete.
• Optimized pore structure significantly enhances thermal insulation efficiency.
• The study provides insights into achieving ultra-lightweight foam concrete with desirable properties for construction applications.