Effect of Selected Admixtures on the Properties of Ordinary Concrete

The article presents the results of laboratory research on the impact of polymer fibres and mineral dust on the properties of hardened concrete. Selected parameters such as compressive strength, flexural strength, water absorption and water capillary action were evaluated. The samples were cured at two temperatures: + 5° C and + 18° C. The polymer fibres added to ordinary concrete increased the resistance to bending and reduced water absorption and capillary action. Addition of mineral dust led to a general improvement of the test parameters, by sealing the cement paste. As shown in the absorption and capillary action tests, the gains in the mass of the samples decreased with the increasing amount of admixture in the form of mineral dust. The mineral dust used for laboratory testing was a waste material derived from an aggregate quarry. The dust is used to a small extent mostly for primers, for example. in the construction of roads. Although treated as a waste material, it has the same properties as original aggregate. Non-hazardous, it still has a negative impact on the environment. The use of aggregate mineral dust can bring a number of advantages, including lower price of concrete mix, improved concrete parameters, waste mineral dust disposal solution, lower cost production of concrete mixtures, and the environmental aspect. Concretes with mineral dust and polymer fibres are a valuable alternative to ordinary concrete.