Evaluation of Rheological, Mechanical, and Durability Properties of Self-compacting Concrete with Microsilica and Diatomite for Application in Buildings Exposed to Marine Environments

Abstract

The research focused on the study of the influence of the partial substitution of cement by microsilica and diatomite on the rheological behavior, compressive strength and permeability of self-compacting concrete. A total of 5 concrete mixes were designed, composed of a standard design, 3 mixes with microsilica (5%, 8% and 10%) and 1 mix with diatomite (5%), keeping constant the w/c ratio (0.40) and the dosage of the plasticizing admixture (1% of the weight of the cement). The following tests were carried out in the fresh state: Temperature, Slump Flow, V-Funnel, L-Box and Air Content; while, in the hardened state, permeability and compressive strength behavior at 3, 7, 14 and 28 days were determined. The results showed that the substitution of 5% microsilica favored the rheological characteristics, while the incorporation of microsilica at 8%, 10% and 5% diatomite decreased the flowability of the concrete. The highest level of permeability was obtained by incorporating 10% microsilica (5.2 mm). In the development of the compressive strength at 28 days, it was identified that all the mixtures exceeded the standard design, obtaining the highest result in the design with 8% microsilica (69.2 MPa). Based on the results, it was concluded that the partial replacement of the binder with microsilica, in an optimum percentage, favors the characteristics of the concrete both in the fresh and hardened state. In this way, a mix with greater durability and strength is obtained.