*Proceeding Paper* **Influence of the Addition of Ground Granulated Blast Furnace Slag, Fly Silica Ash and Limestone on Selected Properties of Cement Mortars †**

**Wacław Brachaczek 1, Adam Chlebo´s 2,\* , Magdalena Kupczak 1, Sebastian Spisak 1, Michał Stybak <sup>1</sup> and Katarzyna Zyrek ˙ <sup>1</sup>**


**Abstract:** This publication presents the results of a study of the effect of partial replacement of cement with waste and natural materials: ground blast furnace slag, fly ash and lime meal on the strength properties of mortars compared to a reference mortar without these additives. In subsequent tests, these materials were gradually replaced with up to 10% CEM I cement. Their effects on consistency and compressive and flexural tensile strengths after 28 days of maturation were investigated. The tests were carried out on blocks measuring 40 mm × 40 mm × 160 mm according to the standard. In the range of tests analysed, the results obtained make it feasible to consider the possibility of partially replacing cement with silica fly ash and ground granulated blast furnace slag in cement mortars.

**Keywords:** ground blast furnace slag; silica fly ash; limestone powder; cement mortar; compressive strength
