Hermes A. Vacca

Pontificia Universidad Javeriana

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Daniel Ruíz

Pontificia Universidad Javeriana

Yezid A. Alvarado

Pontificia Universidad Javeriana

Hugo Alexánder Rondón Quintana

District University of Bogotá

Fredy Alberto Reyes Lizcano

Pontificia Universidad Javeriana

Juan C. Reyes

Pontificia Universidad Javeriana

María C. Borrero

Pontificia Universidad Javeriana

María Pilar León

University of Castilla-La Mancha

Natalia Barrera

Pontificia Universidad Javeriana

Joan M. Larrahondo

Pontificia Universidad Javeriana

María León

Pontificia Universidad Javeriana

Cooperative Institutions

Pontificia Universidad Javeriana

Universidad de Los Andes

Universidad Nacional de Colombia

Universidad de Los Andes

Military University Nueva Granada

Catholic University of Colombia

Universidade de São Paulo

Universidad Politécnica de Madrid

Colombian Army Military Academy "General José María Córdova"

Pilot University of Colombia

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Flexural fatigue performance of a high-thixotropy UHPC

International Journal of Pavement Engineering (2023)

Anny Medicis Hermes A. Vacca Yezid A. Alvarado Orlando Rincón-Arango Daniel Ruíz

ABSTRACTThis research aims to perform a comparison of the mechanical response and the fatigue behaviour of two Ultra-High Performance Concrete (UHPC) mixtures subjected to bending loads: a regular UHPC and a high-thixotropy UHPC. The same materials were used in both mixtures and the only difference was the proportions of water and additive. Rheological tests were performed to validate the thixotropy of mixtures in fresh-state. Additionally, image analysis was applied to get fibre distribution and orientation from beam-cut slices. Thus, the Image pixel complete colour structure (RGB) was analysed to avoid greyscale transformations because of its loss of information. Finally, three-point bending tests were conducted over pre-cracked beams to establish a fatigue equation for the mixtures. Experimental results showed that high-thixotropy UHPC has mechanical properties comparable to regular UHPC.KEYWORDS: UHPCflexural fatiguerheologythixotropy AcknowledgmentsThe research was developed by the Pontificia Universidad Javeriana and Cementos Argos S.A, that contributed with laboratory resources and time of professors and researchers. Also the authors of this work acknowledge and thank the support of the Civil Engineering Laboratory of Pontificia Universidad Javeriana and all technical staff, where the tests were carried out.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was funded by Fondo Nacional de Financiamiento para la Ciencia, la Tecnología y la Innovación Francisco José de Caldas de MinCiencias, Republic of Colombia: Project Code 120380863881 Id: 63881, Rehabilitación de pavimentos con sobrecarpetas de concretos de Ultra Alto desempeño reforzado con fibras de acero UHPFRC. This research was developed by Pontificia Universidad Javeriana, and Argos company which contributed with laboratory resources and time of professors and researchers.

Thixotropy

10.1080/10298436.2023.2282004

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Estimación de la incertidumbre aleatoria de la distorción sísmica de entrepiso de pórticos de concreto reforzado considerando la variabilidad del módulo elástico del concreto de Bogotá

Revista de ingeniería de construcción (2013)

Daniel Ruíz María C. Borrero María León Hermes A. Vacca

Estimación de

10.4067/s0718-50732013000100006

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Bi-axial shaking table tests to evaluate the seismic performance of two-story rammed-earth walls retrofitted with steel plates

Research Square (Research Square) (2023)

Daniel Ruíz Natalia Barrera Juan C. Reyes Yezid A. Alvarado Jesús Daniel Villalba Morales

Abstract Worldwide, unreinforced earthen buildings have shown poor performance during earthquakes, causing deaths and loss of property. The Spaniards that conquest the Americas built with earthen materials for about four centuries and therefore, there are a large number of historic buildings in the northern Andean zone of South America. This territory is geographically located in intermediate and high seismic hazard zones. Over the last few years, the authors proposed a seismic reinforcement system for historic earthen buildings based on A36 steel plates (100 mm x 6.35 mm) installed on both sides of the walls. However, to date, the studies had been focused on tests of one-story buildings subjected to in-plane pseudo-static loads or uniaxial dynamic loads. For this reason, this research assesses the seismic performance of two-story rammed-earth (RE) walls subjected to ground motions using a bidirectional shaking table. Two 1:2 scale RE walls (one retrofitted with steel plates and another unreinforced) were tested. The specimens were two-story walls with a "C" shape, similar to that found in heritage buildings of the Historic Center of Bogota (HCB). Based on the experimental tests, the unretrofitted wall presented irreparable damage at acceleration levels higher than 0.34 g . In contrast, the retrofitted wall had excellent performance with lower damage levels and residual drifts; this specimen was highly resilient, withstanding earthquakes with peak ground acceleration ( PGA ) greater than 0.76 g .

Rammed Earth

Earthquake shaking table

Seismic loading

10.21203/rs.3.rs-2695650/v1

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Mechanical Performance of Commercially Available Premix UHPC-Based 3D Printable Concrete

Materials (2022)

Carolina Medicis Sergio Gonzalez Yezid A. Alvarado Hermes A. Vacca Iván F. Mondragón

Several recent studies have attempted to formulate printable cementitious materials to meet the printing requirements, but these materials are designed to work with specific printing equipment and printing configurations. This paper aims to systematically develop and perform characterization of a commercially available ultra-high-performance concrete-class material (UHPC) modified to be printable. Four percentages of superplasticizer were used (100%, 94%, 88%, 82%) to adjust the UHPC mixture for 3D-printing requirements. A superplasticizer amount of 88% was considered adequate to meet the requirements. Several fresh and hardened properties of UHPC were measured experimentally: shape-retention ability and green strength were investigated in fresh state, and compressive and flexural strength were evaluated in three loading directions to evaluate the anisotropic effects. Furthermore, the strength of the interlayer bond was investigated. The UHPC developed in this study met the criteria for extrudability, buildability, and shape retention to ensure printability. In comparison with mold-cast UHPC, printed UHPC exhibited superior flexural performance (15-18%), but reduced compressive strength (32-56%). Finally, the results demonstrated that a commercially available UHPC-class material can be used for 3DCP, which possesses all necessary properties, both fresh and hardened.

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Cementitious

10.3390/ma15186326

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Estimación de los niveles de desempeño estructural y de la deriva inelástica de pórticos de concreto considerando la variabilidad de los materiales de Bogotá

Ingeniería y Competitividad (1969)

Daniel Ruíz María C. Borrero María Pilar León Hermes A. Vacca

Los ingenieros estructurales calculan la capacidad sísmica de los pórticos de concreto reforzado con la geometría de los elementosestructurales y con las propiedades mecánicas de los materiales. Las propiedades mecánicas más importantes del concreto y elacero usadas para estimar dicha capacidad son: módulo de elasticidad (E) y resistencia a la compresión del concreto (f `c); esfuerzode fluencia (Fy) y esfuerzo resistente del acero (Fu); así como sus deformaciones unitarias. Basados en lo anterior se analizaron estadísticamente los resultados de más de 1,500 ensayos de compresión de concretos (solamente para Bogotá) y más de 900pruebas de tensión de varillas. Luego se modelaron (análisis por elementos finitos tipo “frame” o barra) y diseñaron edificacionesaporticadas de concreto reforzado de 5 pisos de acuerdo con el reglamento colombiano de construcción sismo resistente (NSR-10); y usando dos de los espectros de la microzonificación de Bogotá (año 2010). Usando los modelos de pórticos planoscorrespondientes a uno de los ejes de la edificación y con la generación de números aleatorios de las propiedades mecánicas delacero y el concreto (de acuerdo con los análisis estadísticos de los ensayos de laboratorio) se realizaron 80,000 análisis de pushoverde los pórticos planos seleccionados con el fin de establecer las derivas inelásticas y sus funciones de distribución de probabilidadpara diferentes niveles de daño (simulaciones de Montecarlo). De acuerdo con los resultados, las derivas promedio para alcanzarniveles de daño de fluencia, ocupación inmediata y protección a la vida son 0.51%, 0.84% y 1. 41% respectivamente.

10.25100/iyc.v14i1.2646

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CARACTERIZAÇÃO DINÂMICA DE UMA MISTURA ASFÁLTICA SUBMETIDA Às CONDIÇÕES AMBIENTAIS DE BOGOTÁ

Revista EIA (2010)

Hugo Alexánder Rondón Quintana Fredy Alberto Reyes Lizcano Hermes A. Vacca

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Inter-Laboratory Testing Program for the Physical Characterization of Guamo Sand

Ingeniería e Investigación (2025)

Juan Carlos Ruge Molina Gómez María Camila Olarte Javier Fernando Camacho Tauta Orlando O. Ortíz

In soil testing, assessing physical properties is essential for accurately characterizing sands. However, testing results can vary depending on the experimental procedures used and their implementation. A round-robin exercise facilitates the simultaneous analysis of the reproducibility and replicability of the standard methods used to characterize the properties of a specific material. This paper presents the outcomes of the first inter-laboratory testing initiative (i.e., a round-robin exercise) aimed at assessing the results variability of the physical characterization of a sandy soil. Guamo sand, widely utilized in local research and engineering projects in Colombia, was the focus of this study. 11 national academic laboratories participated in the program, conducting seven replicates of grain size distribution, solids specific gravity, and maximum and minimum void ratio tests. The data provided by all participants were analyzed and interpreted using statistical techniques. The results revealed significant differences between the data collected for each physical property, which can be attributed to the intrinsic variability of this sand’s natural origin and to the use of diverse testing procedures. These comparisons offer valuable practical insights into the discrepancies between the testing methodologies employed by the participants for soil characterization, and they constitute a comprehensive database for future research or practical applications.

Characterization

10.15446/ing.investig.113488

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Fatigue behavior of ultrahigh-performance fiber-reinforced concrete as an alternative for flexible pavement rehabilitation

Ingenieria y Universidad (2022)

Gabriel Frazão Torres Juan Romano Hermes A. Vacca Yezid A. Alvarado Fredy Alberto Reyes Lizcano

The fatigue behavior of ultrahigh-performance fiber-reinforced concrete for use as an overlay in the typical rehabilitation of a flexible pavement structure was analyzed in this study. Compression and four-point bending tests were carried out to characterize the concrete mechanical properties. Fatigue tests were performed using the four-point method, and test beams were evaluated without precracking. The specimens were subjected to constant-amplitude sinusoidal loading with a loading frequency of 10 Hz. The magnitude of each stress level was calculated as a percentage of the initial crack stress. The following results were obtained for the concrete: a compressive strength of 127.1 MPa, bending yield strength of 6.23 MPa, maximum bending stress of 9.89 MPa, Young's modulus of 38.1 GPa, and dynamic modulus of 28.6 GPa. The stress and strain at one million cycles were 6.0 MPa and 166 μm/m, respectively. The fatigue test results indicated superior properties of the ultrahigh-performance concrete to those of similar materials.

10.11144/javeriana.iued26.fbuh

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CARACTERIZACIÓN DINÁMICA DE UNA MEZCLA ASFÁLTICA SOMETIDA A LAS CONDICIONES AMBIENTALES DE BOGOTÁ CARACTERIZAÇÃO DINÂMICA DE UMA MISTURA ASFÁLTICA SUBMETIDA Às CONDIÇÕES AMBIENTAIS DE BOGOTÁ DYNAMIC CHARACTERIZATION OF AN ASPHALT MIXTURE EXPOSED TO ENVIRONMENTAL CONDITIONS OF BOGOTÁ

DOAJ (DOAJ: Directory of Open Access Journals) (2010)

Hugo Alexánder Rondón Quintana Fredy Alberto Reyes Lizcano Hermes A. Vacca

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DYNAMIC CHARACTERIZATION OF AN ASPHALT MIXTURE EXPOSED TO ENVIRONMENTAL CONDITIONS OF BOGOTÁ

Revista EIA (2010)

Hugo Alexánder Rondón Quintana Fredy Alberto Reyes Lizcano Hermes A. Vacca

Characterization

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