This paper involves a practical approach to perform quality-control/quality-assessment of concrete using vibration-based NDT. The first component is the analysis of compressive strength and dynamic E-modulus of concrete samples from various construction projects. The second component involves continuous measurements of E-Moduli as a function of curing time in laboratory-controlled specimens. The experimental program allowed proposing a correlation to predict the expected static and dynamic E-modulus at 28 days from their measurement at any instant of the curing process. A similar relationship is proposed to predict compressive strength at 28 days based on the dynamic E-modulus measured at earlier ages.

This paper presents a comprehensive update of the structural damage assessment of the complex Huaca de la Luna, which is one the most important heritage monuments in northern Peru, and was built by the Moche civilization from 100 AD to 650 AD. The paper presents an overview of the initial hypothesis identified to explain the nature of the damage encountered in the Huaca. The results highlight how the combination of material evaluations, coupled with geotechnical investigations have been essential in constructing a series of 2D nonlinear FE models for the structural analyses under gravitational loading of the Huaca. Results of the analyses conducted to date show the importance of a multidisciplinary approach for assessing the structural safety in these types of buildings. © 2016 Taylor & Francis Group, London.

This research was performed by the Engineering & Heritage research group at PUCP with collaboration from the Department of Structural Engineering of the University of Minho in Portugal. The authors would like to acknowledge the Directorate of Research Management at PUCP (project N° 349-2016) for funding this research. The second author also gratefully acknowledges CONCYTEC for the scholarship in support of her Master studies (Contract N° 027-2015 FONDECYT). Finally, the authors acknowledge the special support provided by the order of the Jesuits and the research assistant Rossemary Enciso.

The study investigates the feasibility of using chitosan biopolymer as an admixture, or as an external coating, for earthen constructions to improve their resistance in two components: water induced degradation and key mechanical properties. The resistance to water induced degradation was evaluated in terms of contact angle and drip erosion tests, while the influence on mechanical properties was measured through compressive, tensile and three-point bending tests. The results indicate that the use of low concentrations of chitosan can improve significantly the performance in the two components and therefore was found to be a promising treatment for new or existing construction.

This research was carried out by the Engineering & Heritage Research Group at PUCP. The authors would like to acknowledge the Pontificia Universidad Católica del Perú PUCP and its funding office DGI-PUCP (project 89-2014) for providing funds to the project within which this work was developed. The authors would also like to thank the fellowship funding for postgraduate studies for the second author by CONCYTEC, PERU (Contract N° 012-2013-FONDECYT). The authors finally acknowledge the support of the Laboratory of Materials at PUCP for providing access to their facilities and equipment.

A survey was conducted in July 2004 to 160 families rearing Guinea pigs in the district of Santa Cruz, Cajamarca, with the aim of characterizing the production system of these animals. Men were more than 50 years of age (44.6%) and wives were mainly between 31 to 50 years old (42%). Primary school was the main grade of instruction. The main labour activity of the head of the family was agriculture (95.4%) and housekeeping for women (97.2%). Raising guinea pigs was mainly driven by the housewife under a family or traditional system. There were 20.4 guinea pigs on average per family, reared regardless of class, sex and age, preferably in the kitchen (88.8%), free (73.8%) or in pools (21.9%). Feeding was based on forages, weeds and kitchen waste. The main diseases reported were ectoparasites (90.1%) and the «plague» (76%). Guinea pigs were used for consumption and sale (71.2%) or only for...

Se realizó una encuesta en julio de 2004 a 160 familias criadoras de cuyes en el distrito de Santa Cruz, Cajamarca, con el objetivo de caracterizar los sistemas de producción de cuyes. El 44.6% de los productores tenía más de 50 años de edad y el 42% de las esposas tenía entre 31 a 50 años. Primaria era el grado de instrucción predominante. La ocupación del jefe de familia era la agricultura (95.4%) y de la esposa era su casa (97.2%). La crianza de cuyes era conducida por el ama de casa bajo un sistema familiar o tradicional. Se encontró un promedio de 20.4 cuyes por familia, criados en un solo grupo sin distinción de clase, sexo y edad, de preferencia en la cocina (88.8%), donde permanecían sueltos (73.8%) o en pozas (21.9%). La alimentación se basó en forrajes, malezas y residuos de cocina. Las principales enfermedades reportadas fueron ectoparásitos (90.1%) y la “pest...

OBJETIVO: Determinar la utilidad del test de la ureasa o test del aliento con carbono 14 en la detección de la infección por Helicobacter pylori (Hp) en pacientes dispépticos del Hospital Nacional Cayetano Heredia. MATERIAL Y MÉTODOS: Se incluyó a 31 pacientes dispépticos que acudieron a la consulta externa del servicio de gastroenterología del HNCH en el mes de setiembre de 2004 y que aceptaron voluntariamente participar en este estudio y a los cuales se les indicó endoscopía alta y biopsia gástrica. A todos ellos se les realizó igualmente el TA, que se realizó con cápsulas de urea marcada con carbono 14 (C14) comercializadas por el Instituto Peruano de Energía Nuclear (IPEN) y con reactivos producidos por el mismo instituto. El diagnóstico de Hp se basó en el análisis histológico con coloración de hematoxilina-eosina. RESULTADOS: De los 31 Test del aliento, hubo un f...

This article presents the results of an experimental campaign using the flat jack technique in an adobe church called “Virgen de la Asuncion” located in Sacsamarca, Peru. The main mechanical properties of this construction were determined using the single and the double flat jack tests. The flat jack test is considered as minor destructive test (MDT), which is appropriate for historical buildings due to the temporary and easily repairable damage generated. Single and double flat jack tests were carried out on the north and east facades of the church. The single flat jack test allowed the estimation of the local compressive stress levels through the continuous monitoring of the state of strain. The double flat jack test allowed determining the local stress-strain behavior in each facade of the church. The mechanical properties obtained in this research are similar to values obtained b...

We determine the long-term growth rate and longevity of an Azorella compacta growing on Misti volcano, near Arequipa, Peru to investigate the species' capacity as a geochronological resource. Using 14C dating on stem pieces sequestered within the plant's cushion, which grows larger through time, we obtain ages of 15 ± 15 14C yrs BP and 165 ± 15 14C yrs BP at depths of 15 cm and 29 cm below the cushion's living surface, respectively. Applying a mixed calibration curve with a Bayesian growth model yields calendar age ranges of 1948–1958 CE and 1802–1935 CE for our 14C dates, respectively. Such ages provide sufficiently precise constraints for investigations requiring dating during the last few hundred years when individual 14C dates yield imprecise calendar age ranges. We infer a long-term growth rate of 1.3–3.5 mm yr?1, corroborating published maximum short-term growth rates. Extr...

A synthesis of a geopolymer binder using spent fluid catalytic cracking (FCC) catalyst is evaluated in this research. Spent FCC catalyst is a solid waste product from the oil refining industry worldwide. It is composed mainly by aluminium and silicon oxides. The silica modulus (Ms), NaOH molar concentration, and liquid/solid (AS/FCC) weight ratio were studied as key factors of the mixture composition for the evaluation of the compressive strength and bulk density of geopolymers. Additional total ratios of SiO2/Al2O3, Na2O/SiO2, and H2O/total solids, which consider chemical composition of the final mixture, were studied. Results indicate that there is an optimum value for each Ms, NaOH molar concentration and AS/FCC that produces the maximum compressive strength. These values also match with the optimized total ratios of SiO2/Al2O3, N2O/SiO2 and H2O/total solids in the mixture, which can ...

This chapter presents the results of a geotechnical and geophysical tests and a Deterministic Seismic Hazard Assessment (DSHA) carried out for the San Pedro Apostol de Andahuaylillas church in Peru, also known as the Sistine Chapel of the Andes for its magnificent paintings. The DSHA is one of the key components of the ongoing seismic vulnerability study led by the Engineering and Heritage research group of the PUCP University, in Lima, Peru. This structural seismic vulnerability study is motivated primarily because of the historical, architectural and artistic features of this church, built circa the late 16th or early 17th century, which was declared part of the Cultural Heritage of Peru in 2010. The church was built by the Jesuits in the sixteenth century over a pre-colombian huaca. Construction for the church was in two main phases. In 1570 construction started with a small chapel an...

Architectural and archaeological heritage is the most representative part of history of a country. For these reasons, over the years, the scientific community has focused its attention on three-dimensional (3D) modeling techniques, conservation, structural analysis and other related applications. Laser scanning, shape from structured light, shape from silhouette, shape from video and shape from photometry are among the techniques that have been used over the past years for 3D modeling of archeological heritage. The application of 3D modeling can be found in several disciplines. In Architecture, it is used to generate digital models from which drawings can be produced. Aerial and terrestrial photogrammetry Photogrammetry is commonly used for digitization of 3D models in different applications due to the fast acquisition process and low cost of equipment. Digitization of structures with te...

La realidad aumentada (AR) aplicada al patrimonio cultural pretende mejorar la experiencia de aprendizaje en sitios arqueológicos, no solo para los visitantes sino también para los investigadores. La estimación de Pose 3D es un problema común en aplicaciones para AR, reconocimiento de objetos, modelado 3D, entre otros. Los sistemas AR utilizan diferentes métodos para estimar la pose de la cámara: detección de bordes y detección de puntos clave, entre otros. La elección del método a utilizar depende de las características del escenario a detectar. En este trabajo se realiza un estudio comparativo de los principales métodos de estimación de pose basados ​​en modelos 3D. Además, presentamos la implementación y validación de un algoritmo de estimación de pose, orientado a la inicialización de un sistema AR aplicado a la “Huaca de la Luna”, una pirámide de ladrillos...

This work was funded by the Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica del Perú (CONCYTEC from its acronym in Spanish), according to the Convenio de Gestión N° 232-2015-FONDECYT. The work was carried out with a collaboration of GETEC and Engineering & Heritage research groups at PUCP.

This research evaluates the effect of the curing conditions on the mechanical properties of geopolymers containing spent fluid catalytic cracking catalyst (SFCCC) generated as a waste by the Peruvian oil-refinery industry. For this purpose, two curing conditions were evaluated: i) sample sealing during oven curing to avoid water loss, and ii) the time before curing (pre-curing time or delay time, before heating). The curing temperature was varied from 25°C up to 100°C. The performance of samples was assessed measuring the compressive strengths and the bulk densities. The results reveal that there are optimal curing conditions associated with the higher compressive strength of the SFCCC-based geopolymers. This optimal condition occurred when water loss was reduced by sealing, and samples were allowed to rest before curing (pre-curing). These two conditions assured not only a higher comp...

The analysis of the evolution of modal properties and its relationship with changes in environmental properties (i.e. ambient temperature and relative humidity) is of high importance since their effects along time can mask the influence of structural damage. While structural monitoring studies to assess the relationship between modal parameters and environmental conditions are abundantly available for modern materials constructions (i.e. concrete or steel), very few studies are reported for adobe buildings. The present paper focuses on the study of the short and long-term structural behavior of existing adobe buildings through the long-term monitoring of ambient vibration and environmental conditions. With this purpose, the paper describes in detail the case study of the San Pedro Apostol Church of Andahuaylillas located in Cusco, inside the Andean region of Peru, a 16th-century church c...

Through long-term monitoring, modal parameters identified in-situ can provide important information about the safety state of civil buildings and infrastructures. Unfortunately, structures are subjected to changing environmental conditions that can mask variations in the dynamic properties caused by damage and, therefore, lead to an incorrect condition assessment. The quantification of the influence of environmental conditions on modal parameters is a crucial step to eliminate their interference in a safety evaluation. Under current state-of-the-art considerations, this step is still an open challenge because environmental variables are time-dependent non-uniform quantities that have different influences on structural systems depending on the predominant material. In this paper, the effects of ambient temperature and humidity on the dynamic properties of earthen constructions are investi...

Geopolymer technology has allowed the development of eco-friendly construction materials with high mechanical properties using industrial wastes and residues. However, geopolymers show fragility and low ductility behavior similar to Portland cement-based materials. This article focuses on the evaluation of jute and sisal fibers as reinforcement of a geopolymer matrix produced from residues of Fired Clay Brick Powder (FCBP). Control samples with no fibers and reinforced matrices with different contents of jute (ranging from 0.5 to 2.0 wt%) and sisal fibers (ranging from 0.5 to 3.0 wt%) were produced to study the effect of the fiber type and content on the mechanical properties of the resulting geopolymer composites. Mechanical characterization consisted of compression, splitting tensile, and three-point bending tests. The results of compression and splitting tensile tests showed the exist...

Las construcciones históricas exigen una vigilancia constante porque los peligros antropogénicos (por ejemplo, el uso, la contaminación o las vibraciones del tráfico) y naturales o ambientales (por ejemplo, los cambios ambientales o los terremotos) pueden poner en peligro su existencia y seguridad. En particular, en la región andina de Sudamérica, las construcciones históricas de tierra requieren especial atención e investigación debido a la alta peligrosidad sísmica de la zona junto a la costa del Pacífico. La monitorización de la salud estructural (SHM) puede proporcionar información útil y en tiempo real sobre el estado de estos edificios. En SHM, la implementación de herramientas automáticas para la extracción de características de los parámetros modales es un paso crucial. Este artículo propone una metodología para la identificación automática de los parámetr...