Hormigones de alta resistencia inicial (24 horas)
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Fecha
2001
Autores
Profesor/a Guía
Facultad/escuela
Idioma
es
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Editor
Universidad Andrés Bello
Nombre de Curso
Licencia CC
Licencia CC
Resumen
Este trabajo tiene por objetivo el estudiar los hormigones de altas resistencias iniciales,
denominados "fast track", este hormigón se utiliza en la reposición y construcción de
pavimentos de calzada, en donde se obtienen resistencias mecánicas de diseño a las 24
horas. También se le denomina comercialmente en el ámbito de plantas de hormigón
premezclado como R1.
Este tipo de hormigón surge de la necesidad de obtener pavimentos con una velocidad de
endurecimiento mayor que el hormigón común, manteniendo el resto de sus propiedades.
El hormigón utilizado en los pavimentos de hormigón vibrado según SERVID Región
Metropolitana debe ser de planta hormigonera, este no acepta la confección de hormigón
"in situ". Pero en la práctica algunas empresas contratistas de los servicios de canalización
subterránea optan hacerlo "in situ", debido a que las cantidades utilizadas son pequeñas y
varían entre 1.6 y 2 m3
• Esto implica un costo elevado del hormigón de planta hormigonera,
no solo por el valor que tiene el hormigón de alta resistencia inicial (HARI) "fast track" en
el mercado, si no también porque esta cantidad significa un valor adicional por m3 no
cargado en el camión, que tiene un mínimo de 6 m3
.
Al ejecutar la mezcla de hormigón "in situ", existe un mayor control de los imprevistos que
surgen en este tipo de obras de canalización subterránea, pero los problemas de hacer la
mezcla de hormigón "in situ" están centrados en el control de las dosificaciones y en la
ejecución de la mezcla de hormigón para el pavimento. Al tomar la alternativa de ejecutar
el hormigón "in situ", se debe probar la dosificación del hormigón en laboratorio y en
terreno. También se deben tener los materiales correctos para ejecutar un HARI "fast
track".
Mediante el estudio de dosificaciones de hormigón con distintos tipos de cemento de alta
resistencia y aditivos, que se ofrecen en el mercado nacional, esta investigación aportará el
conocimiento para llegar a obtener un hormigón de alta resistencia inicial. Además servirá
como información para las empresas constructoras que trabajan con este tipo de hormigón.
Para obtener hormigones con altas resistencias iniciales se ejecutaron mezclas de prueba en
laboratorio manteniendo como constantes, los áridos y la trabajabilidad del hormigón,
fijando un cono de Abrams de 5 cm ± 1 cm. Como variables se consideraron:
El cemento del hormigón, tres tipos de cemento alta resistencia disponibles en el mercado
nacional: dos cementos puzolánicos de alta resistencia y un cemento siderúrgico de alta
resistencia.
Los aditivos: aceleradores de fraguado, plastificantes y superplastificantes. Se estudió cómo
mejoran las resistencias y cualidades del hormigón, su compatibilidad con los distintos
tipos de cementos utilizados, y en qué medida que mejoran las resistencias del hormigón a
las 24 horas y manteniendo una buena trabajabilidad.
De esta manera se obtiene un hormigón de alta resistencia inicial.
This work has the objective to study high resistance concrete (high performance concrete) also knows as "fast track". This type of concrete is used to repair and to build pavements, were mechanical resistance design has been obtained at 24 hours. Also in commercial ambits of concrete plants known as Rl . This type of concrete became a necessity to obtain concrete pavements with a bigger dry speed compare to a normal concrete, keeping all the concrete properties. The concrete mix use in vibrated concrete pavements has to be make at concrete's plants under the SERVIU of the Metropolitan Region of Chile dictated nonns. The Chile's statement <loes not accept in site concrete mix. However in practice many construction contractors of underground piping make in site concrete mix, the reasons are that the quantities of concrete that is need, goes between 1.6 m3 and 2 m3 . This amount of concrete is expensive if it buy it in a concrete plant, not only for the price of "fast track" high resistance concrete mix has in the market, as well as for this amount of concrete there is an additional cost for m3 of concrete that is not in the truck, this minimum amount is 6 m3• When the concrete mix is made in site, exist more control of the factors that are included in this kind of underground piping construction (for example: piping from other companies and broken piping). But the problems of making concrete mix in site are the mix proportion control and the execution ofthe concrete mix by it's self When making in site concrete mix is the alternative, it have to proved that the mixing proportion are correct, it will do it at the laboratory and at field. Also it must have the correct materials to make an high resistan ce concrete "fast track". Through the study of the concrete proportion with different kinds of high resistance cements and concrete admixtures availables in the Chilean market, this investigation will apport the know how to obtain an initial high resistance concrete. Also this study will provide information for the contractors companies that used to work with this kind of concrete mix. The concrete's mixes at the laboratory for obtaining initial high resistance concrete were rnade rnaintaining the concrete's course aggregates and workability, setting the Abrams cone at 5cm ±1 cm. The variable components are: Concrete cements, with three kinds of high resistance cements available at the Chilean market: two ofthem were pozolanic cements and one was a siderucgic cement. Concrete admixtures: accelerator concrete admixtures, plasticizer admixtures and superplasticizer admixtures. It was studied how this concrete admixtures influence the concrete's strength and qualities. Also their compatibility with the available cements and how the admixtures makes a better concrete at 24 hours maintaining concrete' s workability. By this way it will get an inicitial high resistance concrete mix.
This work has the objective to study high resistance concrete (high performance concrete) also knows as "fast track". This type of concrete is used to repair and to build pavements, were mechanical resistance design has been obtained at 24 hours. Also in commercial ambits of concrete plants known as Rl . This type of concrete became a necessity to obtain concrete pavements with a bigger dry speed compare to a normal concrete, keeping all the concrete properties. The concrete mix use in vibrated concrete pavements has to be make at concrete's plants under the SERVIU of the Metropolitan Region of Chile dictated nonns. The Chile's statement <loes not accept in site concrete mix. However in practice many construction contractors of underground piping make in site concrete mix, the reasons are that the quantities of concrete that is need, goes between 1.6 m3 and 2 m3 . This amount of concrete is expensive if it buy it in a concrete plant, not only for the price of "fast track" high resistance concrete mix has in the market, as well as for this amount of concrete there is an additional cost for m3 of concrete that is not in the truck, this minimum amount is 6 m3• When the concrete mix is made in site, exist more control of the factors that are included in this kind of underground piping construction (for example: piping from other companies and broken piping). But the problems of making concrete mix in site are the mix proportion control and the execution ofthe concrete mix by it's self When making in site concrete mix is the alternative, it have to proved that the mixing proportion are correct, it will do it at the laboratory and at field. Also it must have the correct materials to make an high resistan ce concrete "fast track". Through the study of the concrete proportion with different kinds of high resistance cements and concrete admixtures availables in the Chilean market, this investigation will apport the know how to obtain an initial high resistance concrete. Also this study will provide information for the contractors companies that used to work with this kind of concrete mix. The concrete's mixes at the laboratory for obtaining initial high resistance concrete were rnade rnaintaining the concrete's course aggregates and workability, setting the Abrams cone at 5cm ±1 cm. The variable components are: Concrete cements, with three kinds of high resistance cements available at the Chilean market: two ofthem were pozolanic cements and one was a siderucgic cement. Concrete admixtures: accelerator concrete admixtures, plasticizer admixtures and superplasticizer admixtures. It was studied how this concrete admixtures influence the concrete's strength and qualities. Also their compatibility with the available cements and how the admixtures makes a better concrete at 24 hours maintaining concrete' s workability. By this way it will get an inicitial high resistance concrete mix.
Notas
Tesis (Constructor Civil)
Palabras clave
Hormigón de Alta Resistencia