By using crushed brick as aggregate, the structure of concrete can be effectively modeled and materials with very different physical-mechanical characteristics can be obtained. Determination of the influence of polymer admixture on some modified concrete properties is shown in this paper. Experimental work included several types of concrete made with different cement content (250 or 350 kg/m3), and same consistency (slump about 5 cm). Few types of concrete made with 4% admixture of polymer (dry material) by weight of cement. Recycled brick or combination of river sand and recycled brick were used as aggregates. Results of determination of concrete compressive and bending strength, modulus of elasticity, coefficient of thermal conductivity, resistance to freezing-thawing, water permeability, shrinkage and creep, and stress - strain diagram were observed.