4 research outputs found
Use of natural zeolites as ASR inhibitor in basaltic rocks
The capacity of a natural zeolite from the province of La Rioja (Argentina) to inhibit the alkali-silica reaction (ASR) was studied. The pozzolanic material corresponds to a mixture of clinoptilolite zeolite with minor gypsum, quartz and feldspar discarded in spoil heaps in a quarry. An alkali-reactive basaltic aggregate from a quarry in the Argentine Mesopotamia region was used for the study. Two series of tests according to the accelerated mortar bar method (IRAM 1674) were carried out. One set with 0% (control specimen), 10%, 15% and 20% replacement of cement by natural zeolite and another with the same percentages but using milled zeolite. To monitor the reaction process, mortar bars were studied after the test by stereomicroscopy, polarizing microscopy and SEM-EDS. After 16 days of testing, a reduction in expansion (~42 %) was detected in the mortars with 20% replacement by natural zeolite. However, their behaviour was still reactive. On the other hand, the mortars with 20% replacement by milled zeolite produced a 90% reduction in expansion at 16 days, below the limit prescribed by the standard. A simple milling process transforms this material into a good pozzolanic material inhibiting the alkali-reactivity of basaltic aggregates
Zeolite, Study of Aptitude as a Natural Pozzolan Applied to Structural Concrete
Nowadays, concrete is one of the most widely used construction materials due to its low price, appropriate mechanic characteristics and durability. Also, due to its ease to adopt diverse forms and sizes (Najimi et al., 2012). Owing to the importance in the use of concrete as a structural material and to its impact in the environment as a consumer of great quantities of natural resources and emitter of CO2 in the concrete industry, it is necessary to develop, from the science of materials, mixtures that support the growth of the construction industry and that consider the environment. Therefore, it becomes necessary to develop energetically efficient materials. A natural zeolite was studied as a material with potential pozzolanic activity and as partial replacement in different percentages of Portland cement in structural concrete. The results of the mechanic trials in concrete samples prove the feasibility of using this element as pozzolanic material.En la actualidad, el hormig贸n es uno de los materiales de construcci贸n m谩s ampliamente utilizados debido a su bajo precio, apropiadas caracter铆sticas mec谩nicas y de durabilidad, as铆 como por su facilidad de adoptar diversas formas y tama帽os (Najimi et al., 2012). Debido a la importancia del uso del hormig贸n como material estructural de construcci贸n y a su impacto ambiental como consumidor de grandes cantidades de recursos naturales y emisor de CO2 en la industria del cemento, es necesario desarrollar, desde la ciencia de materiales, mezclas que acompa帽en el crecimiento de la industria de la construcci贸n considerando el medioambiente; es decir, desarrollar materiales energ茅ticamente eficientes. Se estudi贸 una zeolita natural como un material con potencial actividad puzol谩nica y como reemplazo parcial en distintos porcentajes del cemento p贸rtland en hormigones estructurales.
Los resultados de ensayos mec谩nicos en hormigones evidencian la factibilidad de utilizar esta adici贸n como material puzol谩nico
Revalorizaci贸n de la fracci贸n pl谩stica de residuos de aparatos el茅ctricos y electr贸nicos (RAEE) / Revaluation of the plastic fraction from electrical and electronic equipment wastes (WEEE)
En las 煤ltimas d茅cadas hubo un crecimiento notable de la cantidad de Residuos de Aparatos El茅ctricos y Electr贸nicos (RAEE), los que son considerados residuos especiales por la Resoluci贸n MAyDS N掳 522/2016. La fracci贸n pl谩stica de RAEE (FPR) constituye aproximadamente el 25% del total en peso, y debido a su composici贸n heterog茅nea y presencia de contaminantes t贸xicos (mayormente retardantes de llama bromados (BFR) y metales pesados) no ha podido ser insertada en circuitos de reciclado apropiado.El agregado de pl谩sticos a morteros, ha sido extensamente estudiado, obteni茅ndose materiales con aptitud t茅cnica para el uso en la construcci贸n. Esto llev贸 a considerar, por parte de emprendimientos locales e incluso reportes cient铆ficos, el uso de la FPR como agregado, en reemplazo total y/o parcial del agregado natural. Estudios previos de nuestro equipo demostraron que este enfoque no impide la lixiviaci贸n de contaminantes y resulta en una tecnolog铆a deficiente e insalubre.Se desarroll贸 un agregado de pl谩stico reciclado (APR) Core-Shell que consiste en un n煤cleo de FPR recubierto con sucesivas capas de cemento y aditivos estabilizantes. El APR desarrollado mostr贸 caracter铆sticas f铆sico-qu铆micas que lo hacen apto para agregar a morteros sin riesgo para la salud.En este trabajo se presentan los componentes fabricados y los resultados primarios de una tecnolog铆a de revalorizaci贸n de un residuo peligroso de una manera responsable, segura y de bajo costo