The effects on the properties of self-compacting mortar of using stainless steel blast furnace slag as a sustainable nano material addition

Abstract

Abstract Voids in cementitious mortar materials cause a drastic reduction in the load carrying capacity of the element. Furthermore, weak interfaces between cement paste and the aggregate creates micro crack initiation and crack propagation. It is therefore very important to decrease these pores and enhance the microstructure homogeneity of cement mortar by adding nano particles. In this article, the properties of self-compacting mortar containing nano blast furnace slag were experimentally assessed. Nano blast furnace slag was prepared and used as an additive for self-compacting mortar in 1, 2, 3, 4, and 5% by weight of cement proportions to generate cementitious sustainable materials. Blast furnace slag was crushed and milled to nano particle size, as checked by Laser Particle Size Analysis, AFM, and FESEM. The self-compacting mortar properties were then tested at 7, 28, and 90 days age. The flowability of self-compacting mortar was determined using the mini flow table and mini v-funnel tests. The experimental results for the hardened mortar showed that the modification and enhancement of the mechanical properties, including compressive strength, flexural strength, and direct tensile strength, increased as the nano powder percentage increased. The total water absorption and porosity were also decreased as the nano powder percentage increased, while the density of self-compacting mortar was decreased. The microstructure homogeneity and nanoparticle distributions of self-compacting mortar were also examined using FESEM.