The present work shows the research carried out on the Evaluation of the behavior of mixtures of clay soil by the addition of steel slag. Given that it is necessary to continue with global trends, to seek solutions to the problems of waste and / or industrial waste, which can generate negative environmental impacts, we see the need to find an adequate use of the large amount of steel slag that generates in Colombia. The methodology used begins with the collection of specialized bibliographic information on the subject of study; This information was analyzed in order to reach a starting point, and thus be able to guide the investigation. Subsequently, different laboratory tests were carried out in order to determine the convenience or not of the addition of steel slag to sub-grades of fine materials. In the investigation an analysis of the obtained results is carried out, in order to determine the best option as a percentage of the mixture of the clay soil (kaolinite clay) with the steel slag and thus deliver a report with the conclusions and recommendations; Likewise, so that in the future we continue to investigate and deepen the topic.