Choosing Conventional Concrete, Ultra-High Performance Concrete or Steel as Material of Construction: An Opinion

Abstract

Ultra-High Performance Concrete (UHPC) is an emerging concrete material that has potential to become a popular choice of material for construction of structures. UHPC is defined as concrete with characteristic compressive strength of anywhere from 120-150 MPa and above combined with superior properties such as high durability, corrosion resistance, low water permeability among many others. However its high tensile strength and cracking behavior is what makes it unique and interesting. UHPC is reported to have 10 to 15 MPa of tensile strength and excellent post-crack behavior as compared to Conventional Concrete (CC). UHPC is reported to indicate strain-hardening behavior when subjected to post-cracking loads. This unique combination of high compressive strength with tensile strength and resilient cracking behavior reminds us of structural steel which is the other major structural building material with similar behavior. In view of these behavioral similarities, an effort has been made in this paper to compare and contrast the properties of UHPC with structural steel. The stress-stain and load-deflection behaviors of both materials are compared. Also a comparison is made between the two materials when subjected to loading beyond post-crack or post-yield regions. To make this study complete, a comparison of material behavior of UHPC, CC and structural steel with regards to their engineering properties, cost, environmental footprint, construction ease and design life is made. All these three materials are rated based on several parameters such as performance, economy, reusability, sustainability, among others. Finally, the order of choice of these three construction materials for various types of structures for typical scenarios is recommended.