Metakaolinite Phosphate Cementitious Matrix: Inorganic Polymer Obtained by Acidic Activation

Area of Science:

• Materials Science
• Inorganic Chemistry
• Construction Materials

Background:

• Aluminosilicate phosphate cementitious matrices are under investigation for novel construction materials.
• Metakaolinite phosphate cement (MKPC) offers a potential alternative to traditional binders.
• Understanding the influence of chemical composition on MKPC properties is crucial.

Purpose of the Study:

• To investigate the synthesis and properties of metakaolinite phosphate cement (MKPC).
• To systematically study the effect of varying Al/P molar ratios on MKPC characteristics.
• To determine the optimal composition of MKPC for enhanced performance.

Main Methods:

• Calorimetric techniques were employed to study MKPC synthesis.
• X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for structural analysis.
• Compressive strength tests were conducted on MKPC mortars (cement/sand ratio 1:3).

Main Results:

• The final MKPC structure was predominantly an amorphous network with some unreacted phases.
• MKPC with Al/P ratios near 1/1 exhibited optimal behavior and high compressive strength (up to 68 MPa).
• High Al/P ratios led to increased porosity and reduced strength, while low ratios resulted in excess phosphates.

Conclusions:

• The Al/P molar ratio significantly influences the microstructure and mechanical properties of MKPC.
• MKPC with an optimized Al/P ratio demonstrates excellent potential as a construction material.
• Further research into MKPC could lead to sustainable and high-performance building solutions.