An improved procedure for obtaining and maintaining well characterized partial water saturation states on concrete samples to be used for mass transport tests

Abstract

A conditioning procedure is proposed allowing to install into the concrete specimens any selected value of water saturation degree with homogeneous moisture distribution. This is achieved within the least time and the minimum alteration of the concrete specimens. The protocol has the following steps: obtaining basic drying data at 50ºC (water absorption capacity and drying curves); unidirectional drying of the specimens at 50ºC until reaching the target saturation degree values; redistribution phase in closed containers at 50ºC (with measurement of the quasi-equilibrium relative humidities); storage into controlled environment chambers until and during mass transport tests, if necessary. A water transport model is used to derive transport parameters of the tested materials from the drying data, i.e. relative permeabilities and apparent water diffusion coefficients. The model also allows calculating moisture profiles during isothermal drying and redistribution phases, thus allowing optimization of the redistribution times for obtaining homogeneous moisture distributions.

Permeability testing of radiation shielding concrete manufactured at industrial scale

“…Also the essential effects of equalization of the humidity distribution in the cross section of specimens were shown. Similar methodological observations resulted from [17], although related to the normal weight concrete. The method of preparation of 100 mm cylindrical specimens with uniformly distributed RH, using the surface RH measurement, is also shown in [18].…”

Influence of moisture condition on chloride diffusion in partially saturated ordinary Portland cement mortar

“…The different humidity circumstances can be controlled by saturated salt solutions [18]. For ''SD'' preconditioning, the sample (often saturated) is firstly dried in an oven at a relatively high temperature to get a preassigned loss of water and then conducted with a moisture redistribution step in order to gain homogeneous moisture distribution [19]. The two approaches were evaluated at the beginning of the sample preconditioning.…”

Comportamiento de hormigones con adiciones puzolánicas y árido reciclado

“…Los ensayos de permeabilidad al aire se realizan a 28 y 365 días sobre secciones centrales de probetas cilíndricas de Ø150mm que fueron cortadas con una altura de 50mm. Como método de acondicionamiento se ha seguido el propuesto por Antón et al (Antón et al, 2013) que permite alcanzar una humedad interior específica en el interior de la probeta, garantizando así que los seis hormigones estudiados se encuentran al mismo grado de saturación (65% en este caso) para poder ser comparados entre sí. El procedimiento consiste primeramente en obtener la capacidad de absorción del hormigón a ensayar mediante la norma ASTM C642-13.…”