X-Ray Absorption Studies of Drying of Cementitious Tile Adhesive Mortars.
X-Ray Absorption Studies of Drying of Cementitious Tile
Bentz, D. P.; Haecker, C. J.; Peltz, M. A.; Snyder, K.
Cement and Concrete Composites, Vol. 30, No. 5,
361-373, May 2008.
x-ray absorption; drying; mortar; adhesives; viscosity;
equations; experiments; mixtures
X-ray absorption measurements have been applied to
studying film formation at the exposed surface during
the drying of cementitious tile adhesive mortars as a
function of ingredients and mixture proportions.
Preliminary observations suggested that in addition to a
drying front, concurrently, a densification front is
observed proceeding from the exterior of the specimens
inward. Due to the extremely high viscosity of the pore
"solution" in these mortars, an analysis based on Stokes
equation actually suggests that some of the smaller
cement particles will be "carried" along with the drying
pore solution to the top surface of the specimen where
they are sequentially deposited. To verify this
hypothesis, further experiments were conducted using
either a coarse cement or a fine limestone as a total
replacement for the commonly used cement. The X-ray
absorption results are further supported by concurrent
mass loss measurements on equivalent specimens for each
experiment and by particle size distribution analysis of
the final dried limestone/silica sand system as a
function of depth.