Curing Concrete Test Specimen

Curing Concrete

Spanish

Curing of concrete test specimens is usually done differently depending on whether the concrete is being placed during construction on site cast in place or tested in a lab. American Society for Testing and Materials (ASTM) has developed two standards for making and curing concrete specimens. ASTM C192 is intended for laboratory samples usually done in a precast plant-like Western, while ASTM C31 is intended for field samples. Both documents provide standardized requirements for making, curing, protecting, and transporting concrete test specimens under field or laboratory conditions, respectively.

ASTM C192 provides procedures for the evaluation of different mixtures in laboratory conditions. It is usually used in the initial stage of the project, or for research purposes. STM C31is used for acceptance testing and can also be used as a decision tool for form and or shoring removal. Depending on its intended purpose, the standard defines two curing regimes: standard curing for acceptance testing and field curing for form/shoring removal. Variation in standard curing of test specimens can dramatically affect measured concrete properties.

According to the National Ready Mix Concrete Association (NRMCA), the strength for concrete air-cured for one day followed by 27 days moist cured will be approximately 8 percent lower than for concrete moist cured for the entire period. The strength reduction is 11 percent and 18 percent for concrete specimens initially cured in the air for three days and seven days, respectively. For the same air/moist curing combinations, but 100 degrees Fahrenheit air curing temperature, the 28-day strength will be approximately 11 percent, 22 percent, and 26 percent lower, respectively.

Dillon Murray – Quality Control Director

Curado de Probetas de Hormigón

El curado de los espedmenes de prueba de concrete generalmente se realiza de maneras diferentes dependiendo de si el concrete se coloca durante la construccion en el sitio o se prueba en un laboratorio . La Sociedad Estadounidense de Ensayos y Materiales (ASTM) ha desarrollado dos estandares para fabricar y curar muestras de concrete. ASTM C192 esta disenado para muestras de laboratorio que generalmente se rea lizan en una planta de prefabricados como Western, mientras que ASTM C31 esta diseflado para muestras de campo. Ambos documentos proporcionan requisites estandarizados para la fabricaci6n, curado, proteccion y transporte de probetas de concrete en condiciones de campo o laboratorio , respectivamente.

ASTM C192 proporciona procedimientos para la evaluacion de diferentes mezclas en condiciones de laboratorio. Por lo general, se utiliza en la etapa inicial del proyecto o con fines de investigacion. ASTM C31 se usa para pruebas de aceptacion y tambien se pu ede usar como una herramienta de decision para la remocion de encofrados y apuntalamientos. Dependiendo de su proposito previsto, la norma define dos reg fm enes de curado: curado estandar para pruebas de aceptacion y curado en campo para remocion de encofrados I apuntalamientos. La variacion en el curado estandar de las probetas puede afectar drasticamente las propiedades medidas del concrete.

Segúm la Asociacion Nacional de Concrete Premezclado (NRMCA), la resistencia del concrete curado al aire durante un dfa seguido de 27 dfas curado en humedo sera aproximadamente un 8 por ciento menor que para el concrete curado en humedo durante todo el perfodo. La reduccion de la resistencia es del 11 por ciento y del 18 por ciento para las muestras de concrete curadas inicialmente al aire durante tres y siete dfas, respecti vamente. Para las mismas combinaciones de curado con aire / humedo , pero con una temperatura de curado con aire de 100 grades Fahrenheit, la resistencia a los 28 dfas sera aproximadamente un 11 por ciento, 22 por ciento y 26 por ciento menor, respectivamente.

Dillon Murray – Director de Control de Calidad

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