Second only to water, concrete is the world’s most consumed material, not surprisingly, concrete contributes to around 8% of global carbon emissions (Gagg, 2014). This motivates researchers to advance in cementitious material and explore possible breakthroughs in an attempt to further improve and optimize the limited available resources. One recent breakthrough in cementitious materials is Ultra High-Performance Concrete (UHPC). UHPC is an advanced class of concrete and cementitious materials that exhibits high mechanical and durability performance. These properties are achievable using packing density theory which optimizes the gradation of granular materials. In other words, UHPC depends on enhanced microstructure, accompanied by a low water/cement ratio and fiber reinforcement to achieve superior overall performance and durability. UHPC typically consists of cement, silica fume, sand, and a fine supplementary material including -but not limited to- fly ash or slag cement. The robustness and popularity of UHPC in different fields has pushed the interest of stakeholders to explore the UHPC tensile capabilities and behaviors. Evidently, there has been a growth in UHPC tensile research. The literature lacks any set of extensive data with variable fiber dosage.In this study, extensive data is examined and commented on. This study is examining a commercial material named CeEntek which consists of sand, cement, water, carbon nanofiber, and superplasticizer. This study’s comprehensive goal is to assess and characterize the tensile behavior of a nanofiber enhanced UHPC.
Another goal of the study is to document the post-cracking tensile behavior of the material. It dictates the future usage of the material as there are two anticipated failure behaviors: failure after gradual strain hardening or failure after crack localization. The first behavior would provide warnings at peak loads which is favorable in general concrete elements design. With the variable fiber percentage in the experimental program, extensive data is generated helping in a better understanding of the tensile behavior of UHPC.
To achieve the mentioned goals, an experimental program was set. The experimental investigation consisted of tests on prims, cylinders, and dog-bone-shaped specimens with varying steel fiber content. Four-point bending, direct tension, and compression tests were carried out according to ASTM specifications and extensive data on their compressive, tensile, and flexural behavior were recorded and analyzed
