EARLY-AGE MECHANICAL PROPERTIES OF MORTARS WITH DIFFERENT PERCENTAGES OF ECO-CEMENT BY

Abstract. Concrete is a mixture between two main components: cement paste and aggregates. While the aggregates and the water can be easily found in nature, cement needs special processing plants to be produced. The production of cement alone has increased dramatically over the past 80 years due to a continuous increase in demand for concrete. Taking into account that the cement content in normal strength concrete ranges from 10 % to 15 % and that the concrete industry is the largest consumer of natural resources in the world, one could only imagine the environmental burden it creates. The present paper brings its contribution to the investigation concerning the use of a new binder, in the form of anhydrous calcium sulphate, as partial or total replacement of the ordinary Portland cement in concrete. The anhydrous calcium sulphate based binder is obtained exclusively from industrial wastes and can be entirely recycled after its expiration date. The obtained results so far show a decrease in the flexural and compressive strengths of mortars with small replacing percentages of anhydrous calcium sulphate compared to the reference sample made with Portland cement. However, the flexural strength increases tremendously for higher percentages of anhydrous calcium sulphate. Additionally, slight gains in the values of the compressive strength were observed for the corresponding specimens compared with the samples for which only small percentages of eco-binder were used. Key words: eco-material; anhydrous calcium sulphate; cement replace-ment; mechanical properties