Materiales reciclados de llantas automotrices y la radiacion gamma en el mejoramiento del concreto

El concreto es uno de los materiales más importantes dentro de la industria de la construcción, esto se debe no solo a su costo sino a las propiedades que presenta como su fácil colocación antes del fraguado, su resistencia al intemperismo, su durabilidad y resistencia. En aras de reducir el impacto ecológico que genera la producción de cemento, se han hecho esfuerzos por disminuir el consumo de recursos naturales no renovables en la fabricación del concreto. En este capítulo se presenta como opción viable para la solución al problema causado por llantas de desecho su reuso en el concreto como sustituto del agregado fino o grueso, procurando la calidad del producto e incrementando las propiedades deseables como la resistencia, el módulo de elasticidad y la durabilidad

Waste tire particles and gamma radiation as modifiers of the mechanical properties of concrete

In polymer reinforced concrete, the Young’s modulus of both polymers and cement matrix is responsible for the detrimental properties of the concrete, including compressive and tensile strength, as well as stiffness. A novel methodology for solving such problems is based on use of ionizing radiation, which has proven to be a good tool for improvement on physical and chemical properties of several materials including polymers, ceramics, and composites. In this work, particles of 0.85mm and 2.80 mm obtained from waste tire were submitted at 250 kGy of gamma radiation in order to modify their physicochemical properties and then used as reinforcement in Portland cement concrete for improving mechanical properties. The results show diminution on mechanical properties in both kinds of concrete without (or with) irradiated tire particles with respect to plain concrete. Nevertheless such diminutions (from 2 to 16%) are compensated with the use of high concentration of waste tire particles (30%), which ensures that the concrete will not significantly increase the cost

Recovery and modification of waste tire particles and their use as reinforcements of concrete

Environmental pollution caused by solid wastes is increasing in the last decades; one of these is referred to automotive tires, which are recycled by differentmethods, includingmechanical grinding. One of the most recurrent applications is to use recycled particles as fillers in building materials, as hydraulic concrete. Nevertheless, detrimental values on the mechanical properties are obtained when they are added. For solving these problems, in this work, a novel proposal is to modify the physicochemical properties of the waste automotive tire particles, previously obtained by grinding process, by using gamma irradiation in order to use them as reinforcements of hydraulic concrete. The results show that improvements on the mechanical properties depend of gamma irradiation as well as concentration and size of waste tire particles. Moreover, SEMimages are related to mechanical properties; for instance, rough surface of the tire particles changes when applying irradiation; more smooth surfaces are created, due to the crosslinking of polymer chains.Nevertheless, for higher doses, cracks are observedwhich are produced by scission of the polymer chains

Reglamento de construcción en madera para la Zona Metropolitana de Guadalajara

En este documento se presentan avances y análisis del reglamento de construcción de la ZMG, tanto la deducción de las ecuaciones de deflexión por flexión y por cortante en los elementos resistentes a fuerzas laterales tales como los muros y diafragmas de madera estructural y también se realizaron pruebas a probetas estandarizadas y normalizadas por la normativa internacional ISO para colaborar los valores de diseño actuales del reglamento de construcción de GDL 2019

M O D U L U S V I V E N D U S

La humanidad siempre ha habitado en lugares de alto riesgo debido a los intemperismos que se pueden presentar en dicho lugar. El reto siempre ha sido el mismo, brindar un habitáculo que sea seguro, accesible y cómodo y esta fue la tarea que se dio a realizar. El proyecto busca un grupo social vulnerable y con la necesidad de una vivienda, dificultades económicas para adquirir una y vivir en una zona de alto riesgo. Para poder proveer un espacio digno para los habitantes y con un crecimiento futuro se previo un diseño modular por marcos, de esta manera podemos crear una casa que sea personalizable, sin perder integridad estructural o poner en riesgo a sus habitantes. Por otro lado, se agregaron tecnologías ecológicas que ya se usan en el sitio, tanto para evitar gastos innecesarios como para generar un sentido de apropiación al inmueble por medio de este cuidado al medio ambiente y a ellos mismo

Novel Porous Materials Solution for Instability Decrease of Problem Soils under Buildings

Problem clay soils represent a great cracking problem for all light buildings over them because of volumetric instability caused by variations in moisture. A generalized solution has been to extract them and substituted by inert soil, thus they become construction trash. A foundation solution to solve the problem of soil is inverted ribbed slab which generates hollow spaces between the soil and the slab for the soil movement. Therefore this work presents a novel solution for reducing instability of soils based on the inclusion of natural porous material within its structure. After results, we conclude that porous material placed within the soil decreased their growth favorably and it depended on its natural void volume. In fact total vertical deformation of the soil (by volume) was decreased with only 65% of its value within the voids when it theoretically should be equal to the vertical volume deformed. This is probably due growth pressure soil was redirected into the porous which generates greater density in the soil introduced requiring less void volume of the total volume deformed. So, according to the natural growth of the clay soil we may include porous materials with the amount of void volume required for such growth

Ivabradine in acute heart failure: Effects on heart rate and hemodynamic parameters in a randomized and controlled swine trial

Background: Acute heart failure patients could benefit from heart rate reduction, as myocardial consumption and oxidative stress are related to tachycardia. Ivabradine could have a clinical role attenuating catecholamine-induced tachycardia. The aim of this study was to evaluate hemodynamic effects of ivabradine in a swine model of acute heart failure. Methods: Myocardial infarction was induced by 45 min left anterior descending artery balloon occlusion in 18 anesthetized pigs. An infusion of dobutamine and noradrenaline was maintained aiming to preserve adequate hemodynamic support, accompanied by fluid administration to obtain a pulmonary wedged pressure ≥ 18 mmHg. After reperfusion, rhythm and hemodynamic stabilization, the animals were randomized to 0.3 mg/kg ivabradine intravenously (n = 9) or placebo (n = 9). Hemodynamic parameters were observed over a 60 min period. Results: Ivabradine was associated with a significant reduction in heart rate (88.4 ± 12.0 bpm vs. 122.7 ± 17.3 bpm after 15 min of ivabradine/placebo infusion, p < 0.01) and an increase in stroke volume (68.8 ± 13.7 mL vs. 52.4 ± 11.5 mL after 15 min, p = 0.01). There were no significant differences in systemic or pulmonary arterial pressure, or significant changes in pulmonary capillary pressure. However, after 15 min, cardiac output was significantly reduced with ivabradine (–5.2% vs. +15.0% variation in ivabradine/placebo group, p = 0.03), and central venous pressure increased (+4.2% vs. –19.7% variation, p < 0.01). Conclusions: Ivabradine reduces heart rate and increases stroke volume without modifying systemic or left filling pressures in a swine model of acute heart failure. However, an excessive heart rate reduction could lead to a decrease in cardiac output and an increase in right filling pressures. Future studies with specific heart rate targets are needed

Ivabradine in acute heart failure: Effects on heart rate and hemodynamic parameters in a randomized and controlled swine trial.

Background: Acute heart failure patients could benefit from heart rate reduction, as myocardial consumption and oxidative stress are related to tachycardia. Ivabradine could have a clinical role attenuating catecholamine-induced tachycardia. The aim of this study was to evaluate hemodynamic effects of ivabradine in a swine model of acute heart failure. Methods: Myocardial infarction was induced by 45 min left anterior descending artery balloon occlusion in 18 anesthetized pigs. An infusion of dobutamine and noradrenaline was maintained aiming to preserve adequate hemodynamic support, accompanied by fluid administration to obtain a pulmonary wedged pressure ≥ 18 mmHg. After reperfusion, rhythm and hemodynamic stabilization, the animals were randomized to 0.3 mg/kg ivabradine intravenously (n = 9) or placebo (n = 9). Hemodynamic parameters were observed over a 60 min period. Results: Ivabradine was associated with a significant reduction in heart rate (88.4 ± 12.0 bpm vs. 122.7 ± 17.3 bpm after 15 min of ivabradine/placebo infusion, p < 0.01) and an increase in stroke volume (68.8 ± 13.7 mL vs. 52.4 ± 11.5 mL after 15 min, p = 0.01). There were no significant differences in systemic or pulmonary arterial pressure, or significant changes in pulmonary capillary pressure. However, after 15 min, cardiac output was significantly reduced with ivabradine (–5.2% vs. +15.0% variation in ivabradine/placebo group, p = 0.03), and central venous pressure increased (+4.2% vs. – 19.7% variation, p < 0.01). Conclusions: Ivabradine reduces heart rate and increases stroke volume without modifying systemic or left filling pressures in a swine model of acute heart failure. However, an excessive heart rate reduction could lead to a decrease in cardiac output and an increase in right filling pressures. Future studies with specific heart rate targets are needed.pre-print2533 K