COMPARING THE ENVIRONMENTAL, ECONOMIC AND PERFORMANCE INDICES OF VARIOUS FIBER-REINFORCED CEMENT COMPOSITES

Abstract

Concrete is the most widely used building material in the world. The single largest limitation of concrete is its weak and brittle nature under tensile stress. To improve concrete behavior, reinforcement materials that are strong in tension are embedded into the concrete to avoid brittle failure and increase tensile capacity. Besides the traditional methods of embedding continuous aligned reinforcement in anticipated zones of tensile stress, random discrete fibers can be dispersed into the concrete during the mixing procedure to create a composite material called fiber reinforced concrete (FRC). Distinctive fiber filaments are used to improve the ductility and strain-hardening of cementitious composite mortars and grouts. Fibers vary commercially and environmentally so that polyvinyl alcohol (PVA) fibers are relatively expensive and might have higher environmental impact than Portland cement, polypropylene (PP), steel, basalt, and glass. Limited studies compared the effects of different fibers (PVA, PP, basalt, steel, and glass) on the hardened mechanical properties of normal-strength concrete mixtures, and on the behavior of structural members cast with such concrete mixtures. Moreover, many research studies addressed the issue of low tensile strength of concrete by adding fibers [1]. Based on that, this study aims to compare five different types of fiber reinforced cement composites, which are used in normal strength grade concrete based on their structural properties, environmental impacts, and cost. The five types of fibers are Basalt fiber (BF), Glass fibers (GF), Polypropylene fiber (PPF), Polyvinyl alcohol fiber (PVAF), and steel fiber (SF). The annual cement production in the world is over 4.4 billion tons. Moreover, the projected amounts by 2050 will reach over 5.5 billion tons [41]. This rapid growth of the construction sector leads to the consumption of natural resources and energy, which makes it essential to find more sustainable solutions for the future generations. So, in this research project, the environmental impacts and costs of different fibers and fiber-reinforced mixes that show good performance are studied. Lifecycle assessment from cradle- to- gate are performed for producing and receiving one kilogram of each kind of fibers using various environmental categories like Global Warming, Eutrophication, Toxicity, and Ozone Depletion, etc. Additionally, the life cycle assessment is done for 15 concrete mixes prepared at AUB laboratory and that reached acceptable mechanical properties. This research project helps in finding the most convenient composite from different aspects and highlights the phases in production and transportation which need improvement for a sustainable use of fibers in reinforced cement composites.