Effect of Selected Fibers on Mortar Parameters

The optimal use of fibers in construction brings tangible benefits, and in many cases even makes it possible to overcome the limitations of traditional reinforcement. Concrete with dispersed reinforcement belongs to the group of special concretes, which are characterized by special properties, i.e. resistance to the formation of cracks and fractures, higher fatigue resistance, as well as higher tensile and shear strength. Increasing demands on structural components have forced contractors to look for innovative solutions. This means that a mixture of only three ingredients doesn't really exist anymore. Selected chemical admixtures and mineral additives are being added to concretes, as well as various types of dispersed reinforcement. The use of fibers significantly improves selected properties of concretes. Therefore, an attempt was made to compare the rheological characteristics and parameters of hardened mortars with selected types of fibers that are generally available on the market. In the literature we can find a lot of research on concrete modification. In contrast, knowledge of the use of fibres in construction mortars is to a much lesser extent. The aim of the study was to determine the physico-mechanical parameters of mortars with the addition of steel, glass and basalt fibres. The effects of fibre addition on the compressive and flexural strength, water absorption and capillary rise of mortars were studied. The rheological characteristics of the mortars, i.e. consistency and bulk density, were also studied. Compressive and flexural strength were tested after 7, 28 and 56 days, while capillary rise and saturation were tested after 28 days of maturation. Relationships were developed for the mortars tested between compressive strength and flexural strength, as well as absorbability and capillary rise. A full statistical analysis was performed for two parameters, i.e. compressive strength and capillary rise. The flexural strength at each test time is definitely influenced by the type of dispersed reinforcement used in the mortar. In the absorption and capillary rise tests, each type of fibre in the mortar results in a reduced weight gain in contact with water.