The present study evaluated the mechanical characteristics of Ultra-High Performance Concrete (UHPC) used for the construction of rigid pavements by modifying its rheological behavior, defined here as the workability, consistency and fluidity of a concrete. For the present study, 5 UHPC concrete mixes were made, of which 4 had their additive content varied with respect to a reference mix. The methodology consisted of 2 stages. The first stage encompassed the rheological characterization of the 5 freshly made concrete mixtures in the laboratory using the following 3 rheological parameters: (1) flow resistance and viscosity (measured by a cutting rheometer), (2) mixture flow (measured by a mini-slump) and (3) consistency (measured by a settlement test). In the second step, the mechanical properties of the 5 concrete mixtures were evaluated in the laboratory, by measuring the following parameters: (1) compressive strength of concrete cylinders, (2) elastic modulus of concrete, and (3) flexural strength of concrete in beams loaded at the center point or middle thirds. It was found that the rheological behavior of the mixtures changed as a function of the additives used, as well as a function of time. On the other hand, it was found that the mechanical properties of UHPC concrete were affected, in terms of compressive strength by obtaining a decrease in value of 28% as significant data. The other mechanical properties evaluated as flexural stress, elastic modulus and density did not experience significant changes.
Modificación del comportamiento reológico del concreto UHPC como alternativa de diseño y construcción para pavimentos
HURTADO TINOCO, J. D. (Author). 2020
Student thesis: Master's Thesis