Improving the eco-efficiency of fiber reinforced composite by ultra-low cement content/high FA-GBFS addition for structural applications: Minimization of cost, CO2 emissions and embodied energy

Abstract

In recent years, a great deal of importance has been attached to production based on the UN's sustainable development goals in the construction sector. Environmental solutions are sought for sustainable cities and communities during the concrete design and production stages. For this purpose, the properties of low-cement composites are frequently investigated. In this study, polypropylene (PP) fiber reinforced concrete with 10 or 20 kg/m3 PP fibers and a cement content of 200 kg/m3 was produced. In addition to cement, 800 kg/m3 slag or fly ash (FA) was used in the blends. Fresh, physico-mechanical, durability, microstructure, environmental and financial properties of the blends were investigated comparatively. Addition of PP fiber reduced the fluidity of the blends. Oven-dry densities of the blends are lower than 2000 kg/m3 91-day compression strength of slag-blended blends varies between 27.8 and 44.8 MPa, and the blends with FA addition vary between 23.4 and 30 MPa. While the 91-day splitting-tensile strength of the slag blends exceeded 3.0 MPa, the blends with FA remained below 2.0 MPa. Capillary water absorption values of the blends vary between 0.36 and 1.23 kg/m2. Addition of PP fiber increased the resistance of the blends against deteriorations such as freeze-thaw, sulfate and wear. In SEM images, fiber stripping was observed in blends with FA. By using slag and FA, the carbon emissions and embodied energy of the blends were reduced 4 times than the reference blend. In addition, the cost of the blends varies between 15.2 and 153.5 USD/m3. The addition of PP fiber had a negative effect on the sustainability and financial properties of the composites. As a result of minimization, it was determined that the combined use of slag and FA was more appropriate. It has been determined that the blends obtained can be used in structural applications and mass concretes.