The investigation of microgranular constituents of magnesia concretes should be made in order to obtain further improvements in the quality. Microgranular constituents from periclase powder, sintered dunite, and chromite are the most common materials for magnesia concretes. The authors therefore studied the thermomechanical properties of pressed and cast TABLE 1 Chemical Composition of Original Materials Material ~ ~madd Periclase powder fractions 3-0 mm 18~2, 42 1 !,55 [ !,44 1 -[ o,sa Sintered Solov evogorsk dunite fractionsl-0 rnm 149,02140,28 I 0,17 I 0,24 I 9,79 ] 0,48 ~Nt. inc. Kempiraiskchromiteorefractions10mm I.lOl.Ol0Oo Io7o 1,33o1 9ol ,78 *Here and subsequently mass proportions are indicated.