Synthesis and Rheological Property of Calcium Aluminate Cement Containing MgAl$lt;inf$gt;2$lt;/inf$gt;O$lt;inf$gt;4$lt;/inf$gt; Spinel

Calcium aluminate cements with different MgAl 2 O 4 spinel (CMA) contents and particle sizes were synthesized. The results revealed that when the synthesis temperature was raised from 1400 to 1500, the particle size of MgAl 2 O 4 (MA) increased from 5 m to 15 m. The MA particles appeared in clusters and were distributed around the CaAl 2 O 4 /CaAl 4 O 7 (CA/CA 2 ) particles for CMA synthesized at 1400, while MA particles were inserted in the CA/CA 2 particles for CMA synthesized at 1500. At the same time, the setting time lengthened and the viscosity decreased with the increase in MA content and particle size for CMA. The corresponding minimum values of storage modulus and flow point were 0.15 MPa and 4.44%, respectively. It is believed that the higher content of the MA phase and the larger particle size of CA/CA 2 particles in CMA cement can result in a weak flocculation structure in hydrates.