To experience a miracle just add graphene to concrete during the production process. Graphene concrete is twice as strong, four times as water resistant, with a smaller carbon footprint compared to the conventional processes. Graphene reduces the amount of materials needed in concrete production by nearly 50 percent and reduces carbon emissions by 446 kg per ton. Center for Graphene Science, University of Exeter, United Kingdom. See: http://www.exeter.ac.uk/news/featurednews/title_654766_en.html
It probably will not be commercially available for fixing the terrace this summer.