Análisis de las propiedades físicas y mecánicas del residuo de caucho de neumático como reemplazo parcial del agregado fino en el hormigón

El objetivo del presente estudio es evaluar las propiedades físicas y mecánicas del hormigón con residuos de caucho de neumático (RCN) como sustituto parcial a la arena, considerando materiales locales de la ciudad de Cochabamba, Bolivia, a fin de promover una economía circular. Para ello, se sustituyó la arena por RCN (en volumen) en cuatro porcentajes: 0% (referencia), 5%, 10% y 20%, evaluando sus propiedades mecánicas (resistencia a la compresión, tracción y flexión) y físicas (masa específica, absorción de agua e índice de vacíos). Los resultados indican que existe una tendencia a la disminución a mayor porcentaje de RCN, tanto para la resistencia mecánica como para las propiedades físicas, a excepción de la mezcla con 5% de RCN, la cual presentó resultados comparables al hormigón con arena natural. El RCN puede ser utilizado en la elaboración local de hormigón hasta en un 5% sin comprometer sus propiedades mecánicas y físicas, y brinda además un enfoque sostenible.O objetivo do presente estudo é avaliar as propriedades físicas e mecânicas do concreto com resíduos de borracha de pneus (RCN) como substituto parcial da areia, considerando os materiais locais da cidade de Cochabamba, Bolívia, com o intuito de promover uma economia circular. Para este fim, a areia foi substituída por RCN (por volume) em quatro porcentagens: 0% (referência), 5%, 10% e 20%, avaliando suas propriedades mecânicas (resistência à compressão, à tração e à flexão) e propriedades físicas (massa específica, absorção de água e relação de vazios). Os resultados indicam que há uma tendência à diminuição com uma maior porcentagem de RCN tanto para a resistência mecânica quanto para as propriedades físicas, com exceção da mistura de 5% de RCN, que mostrou resultados comparáveis ao concreto com areia natural. O RCN pode ser usado na produção local de concreto até 5% sem comprometer suas propriedades mecânicas e físicas e proporciona uma abordagem sustentável.The objective of this study is to evaluate the physical and mechanical properties of concrete with waste tire rubber (WTR) as a partial substitute for sand, considering local materials from the city of Cochabamba, Bolivia, to promote a circular economy. The sand was replaced by WTR (in volume) in four percentages: 0% (reference), 5%, 10%, and 20%, evaluating its mechanical properties (resistance to compression, traction, and bending) and physical properties (specific mass, water absorption, and void index). The results indicate that there is a tendency to decrease with a higher percentage of WTR, both for mechanical resistance and for physical properties, except for the mixture with 5% WTR, which had results comparable to concrete with natural sand. WTR can be used in the local production of concrete up to 5% without compromising its mechanical and physical properties, in addition to having a sustainable approach

Implementación de conceptos y herramientas de la filosofía Lean Construction en las empresas constructoras de la Ciudad de Cochabamba – Bolivia

The objective of this study is to identify the strategies used by the construction companies of the city of Cochabamba-Bolivia in the execution of projects, considering the tools and concepts of Lean Construction. The methodology consisted of a survey of 63 companies in the city of Cochabamba-Bolivia through a questionnaire made up of 44 questions. Four aspects were consulted: a) profile of project managers, b) general company information, c) planning and execution of projects and d) knowledge of the Lean Construction philosophy. The results show that companies recognize the problems in productivity and generation of waste, but do not carry out specific solutions. On the other hand, companies have listened to and even implemented some Lean Construction tools; however, the majority (70%) do not know the philosophy. Although barriers to implementing the philosophy are identified, actions that can collaborate in its application are also highlighted, such as demonstrating results with benefits and training staffEl objetivo del presente estudio es identificar las estrategias utilizadas por las empresas constructoras de la ciudad de Cochabamba-Bolivia en la ejecución de proyectos, considerando las herramientas y conceptos de Lean Construction. La metodología consistió en una encuesta a 63 empresas de la ciudad de Cochabamba-Bolivia mediante un cuestionario conformado por 44 preguntas. Se consultaron cuatro aspectos: a) perfil de los encargados de proyectos, b) información general de la empresa, c) planificación y ejecución de proyectos y d) conocimiento de la filosofía Lean Construction. Los resultados muestran que las empresas reconocen los problemas en la productividad y generación de desperdicios, pero no realizan soluciones específicas. Por otro lado, las empresas han escuchado e incluso implementando algunas herramientas de Lean Construction; sin embargo, la mayoría (70%) no conoce la filosofía. Si bien se identifican barreras para implementar la filosofía, también se resaltan acciones que pueden colaborar en su aplicación, tales como demostrar resultados con utilidades y capacitar al personal

Impacto de la cuarentena de COVID-19 en empresas constructoras de Cochabamba, Bolivia

The COVID-19 pandemic has led countries to implement biosecurity and quarantine measures to prevent the spread of COVID-19; However, this situation has caused several sectors of the world economy to be in crisis, including construction. In this context, the objective of this article is to determine the impact of the COVID-19 quarantine on construction companies in Cochabamba, Bolivia. The methodology consisted of acquiring data through an online questionnaire from 42 construction companies in Cochabamba, Bolivia. The results show that there is a considerable reduction in income and personnel. The cost of labor increased more than materials, equipment and services. The greatest difficulties presented during the quarantine were: lack of payment by public institutions, limited credits from banks and physical delays in projects. It is necessary that the competent public entities generate policies and strategies to help in the recovery of the construction sector, being one of the most important within the Bolivian and world economy.Debido a la pandemia de COVID-19 varios países implementaron medidas de bioseguridad y cuarentenas para evitar su propagación; sin embargo, esta situación ha provocado que varios sectores de la economía mundial estén en crisis, incluida la construcción. En este contexto, el objetivo del presente artículo es determinar el impacto de la cuarentena de COVID-19 en empresas constructoras de Cochabamba, Bolivia. La metodología consistió en la adquisición de datos mediante un cuestionario en línea a 42 empresas constructoras en Cochabamba, Bolivia. Los resultados muestran que existe una reducción considerable de ingresos y personal. El costo de la mano de obra se incrementó más que los materiales, equipos y servicios. Las mayores dificultades presentadas durante la cuarentena fueron: la falta de pago por parte de instituciones públicas, limitados de créditos por parte de los bancos y retrasos físicos en los proyectos. Es necesario que las entidades públicas competentes generen políticas y estrategias para ayudar en la recuperación del sector de la construcción, siendo uno de los más importantes dentro de la economía boliviana y mundial

Compressive Strength Assessment of Soil–Cement Blocks Incorporated with Waste Tire Steel Fiber

The rapid growth in waste tire disposal has become a severe environmental concern in recent decades. Recycling rubber and steel fibers from wasted tires as construction materials helps counteract this imminent environmental crisis, mainly improving the performance of cement-based materials. Consequently, the present article aims to evaluate the potential use of waste tire steel fibers (i.e., WTSF) incorporated in the manufacture of soil–cement blocks, considering their compressive resistance as a primary output variable of comparison. The experimental methodology applied in this study comprised the elaboration of threefold mixtures of soil–cement blocks, all of them with 10% by weight in Portland cement, but with different volumetric additions of WTSF (i.e., 0%, 0.75%, and 1.5%). The assessment’s outcomes revealed that the addition of 0.75% WTSF does not have a statistically significant influence on the compressive resistance of the samples. On the contrary, specimens with 1.5% WTSF displayed a 20% increase (on average) in their compressive strength. All the tested samples’ results exhibited good agreement with the minimum requirements of the different standards considered. The compressive resistance was evaluated in the first place because it is the primary provision demanded by the specifications for applying soil–cement materials in building constructions. However, further research on the physical and mechanical properties of WTSF soil–cement blocks is compulsory; an assessment of the durability of soil–cement blocks with WTSF should also be carried out