**Francisca Perez-Garcia 1, Maria Eugenia Parron-Rubio 2,\*, Jose Manuel Garcia-Manrique <sup>1</sup> and Maria Dolores Rubio-Cintas <sup>2</sup>**


Received: 18 March 2019; Accepted: 8 April 2019; Published: 10 April 2019

**Abstract:** This paper is part of a research line focused on the reduction of the use of cement in the industry. In this work, the study of work methodologies for the manufacture of green cementitious grout mixtures is studied. Grout is widely used in construction and it requires an important use of raw materials. On the other hand, the steel industry faces the problem of the growing generation of slag wastes due to the increase in steel manufacturing. The green grout aims to achieve the dual objective of reducing the demand for cement and improve the slag waste valorization. Slag is not introduced as an aggregate but through the direct replacement of cement and no additives. The research seeks a product where we can use steel slag intensively, guaranteeing minimum resistance and workability. Results with substitutions between a 25% to 50% and water/cement ratio of 1 are presented. In particular, the suitability of different slags (two Ladle Furnace Slag (LFS) and one Blast Furnace Slag (GGBS)) in the quality of the final product are analyzed. The feasibility of replacing cement with slag and the importance of the origin and pretreatment are highlighted.

**Keywords:** cementitious grout; green grout; cement; slag substitution; valorization; circular economy
