Comparison of the effectiveness of microsilica modification of lightweight concretes with coarse aggregates from various rocks

A promising line of research in construction science and practice is the creation of lightweight concretes. They exhibit the so-called strength-density ratio, i. e. a relative characteristic between the strength and weight of the resulting concrete. This ratio simultaneously reflects the maximum possible weight reduction of the structure and its operational reliability. The research aims to compare the effectiveness of microsilica modification of lightweight concretes produced with coarse aggregates from various rocks. The study analyzed the existing scientific literature on lightweight concretes, their formulations, technology, and scientific validity, as well as the structural compatibility of the components used. A comparison was made of the effectiveness of lightweight concrete modification for various formulation technological parameters. The strength of modified lightweight concrete and its strengthdensity ratio changed significantly compared to unmodified lightweight concrete. The strongest effect is achieved when using lightweight granite concrete modified with 9 % of microsilica. As a result, the maximum compressive strength was 55.9 MPa, and the strength-density ratio was 24.3•10-3 MPa•m3/kg compared to other studied concrete compositions. The increase in compressive strength was 17.2 % compared to unmodified lightweight concrete. The strength-density ratio increased by 19.1 % compared to unmodified coarse dense aggregate concrete.