Abstract
Concrete, which is one of the most important construction materials, despite its many advantages (ease of use, high compressive strength, low production cost, resistance to high temperatures) also has disadvantages. These include low tensile strength and sensitivity to the damaging effects of chemical agents. The constant increase in expectation of increasing the quality of concrete has led to the modification of concrete with polymers. The presented research observed the influence of the structure and length of polymer fibers on the properties of concrete. The following types of concretes were used in the study: Portland cement CEM I 42.5R, sand, gravel aggregate of fractions 2-8 mm and 8-16 mm, water, Master Pozzolith STD plasticizer and polypropylene fibers of different length and structure. For each series of concretes, the following were determined: compressive strength after 7, 28 and 56 days of maturation, as well as water absorption, bulk density and frost resistance. In the next stage of the research, the surface layer of the synthesized composites was analyzed, determining mainly their morphology and elemental composition.