Complex Modulus characterization of an Optimized Binder with SCMs: proposition of an enhanced Cement formulation to improve Stiffness Behavior and Durability of Mortars and Concretes

Materials optimization is an aspect of continuous endeavor for civil engineering in many applications, especially in construction where the materials’ durability and mechanical performance are crucial for structural integrity. Structures such as aerogenerators, both towers and foundations, are highly exposed to cyclic loads with a broad range of frequencies and levels. The improvement of the stiffness behavior can significantly enhance their fatigue resistance and consequently durability. This paper aims to evaluate the impact of a high-performance binder optimization, using supplementary cementitious materials (SCMs) to improve the mechanical behavior of mortars and concretes, by improving stiffness response under cyclic loadings, which is related to durability and fatigue life-service. Static tests (axial compressive and splitting tensile strengths) were conducted as well as cyclic stiffness tests that were proposed as a new methodology for these kinds of materials, which may better relate the mechanical behavior in field applications. The proposition consists of complex modulus tests, under sinusoidal loading, either in pure compression and pure tension, adopting low (0.1–1 Hz) and mid-range (1–25 Hz) loading frequencies. The results show that the optimized binder resulted in a superior material with up to 23% stiffer loading response and 13.8% more energy storage elastically, with also inferences on improved durability, which is expected to delay pathological manifestations, and extended fatigue-life. The proposed testing protocol obtained results compatible with the literature and seems applicable for evaluating the dynamic behavior of cementitious materials.