A Procedure to Measure the Diffusion Coefficient of Water in Brick as a Function of the Water Concentration

A Gravitational Procedure to Measure the Diffusion Coefficient of Water in Porous Materials: A Case Study on Concrete

“…The proposed procedure is better than the procedure proposed by van der Zanden and de Wit, [7] because in their procedure, the measured masses depend on their drying flux and the diffusion coefficient, while in the present procedure there is no drying flux. The reaching of the new equilibrium, the time evolution of the measured masses, depends only on the diffusion coefficient.…”

“…The precise equations for M L and M R follow from the mechanical no-rotation conditions. [6,7] If the mass difference is not large enough, it can be increased by moving the cables closer to each other. This way, the sensitivity of the measuring procedure can be increased.…”

“…A detailed description of this method was given by van der Zanden and de Wit. [7] It has been shown that the diffusion coefficient is very often a function of the water content-for instance, for gas concrete, [9] for parboiled rice, [10] and for pineapple. [11] The preceding steps give the value of the diffusion coefficient only at one water content of the sample.…”

“…How the diffusion coefficient is obtained from the measured masses is not described in the present paper, but is presented by van der Zanden and de Wit. [7] Finally, we examine theoretically how the proposed procedure would work out for a sample of concrete.…”

“…This way, more information is obtained from the drying experiment compared to the situation where only the total mass is measured with one balance. Van der Zanden and de Wit [7] studied the accuracy of this drying procedure when the used balances have a given inaccuracy. This technique is similar to the technique proposed by Gaffner, [8] who measured the mass at one end of a sample, while the other end was resting on a support.…”