Stucco Analysis

The phenomenon of thermal transpiration was discovered by Osborne Reynolds [82], who gave a clear and detailed description of his experiments, together with a theoretical analysis, in a long memoir read before the Royal Society in February of 1879. He experimented with porous plates of stucco, ceramic and meerschaum and, in the absence of pressure gradients, found that gas passes through the plates from the colder to the hotter side. His experimental findings were summarized in the following "laws" of thermal transpiration. 

Montes, L. T., M. R. Garcia, J. Gazzola, and S. Gomez (2005), Analysis of stucco floors from the citadel of the archaeological zone of Teotihuacan, Mexico, Materials Research Society Symposium Proceedings (Materials Issues in Art and Archaeology VII) 852, 353-359. 

After calcination, the stuccos were cooled to room temperature with constant stirring to remove all entrained water vapor. The residual gypsum content and soluble anhydrite content as determined by phase analysis 9] were always less than 4.0 and 2.0%, respectively. 

The particle size distribution of the dry stucco was measured using a Sedi-graph 5(XX)D particle size analyzer. Specimens were prepared by dispersing the stucco in Sedisperse A-11 and placing the suspension in an ultrasonic bath for 2 min. Data were acquired in the form of a cumulative mass percent versus equivalent spherical diameter curve. As demonstrated in Fig. 1, this analysis included particles with an equivalent spherical diameter as small as 0.325 xm. For all specimens tested, the particles had equivalent spherical diameters smaller than 90 )im. 

Figures 3 through 6 illustrate the effect of aging time on consistency and disintegration, as well as the relationship between consistency and disintegration for continuously calcined Terra Alba. These data show that both consistency and disintegration decrease with time and suggest a linear relationship exists between these properties. Regression analysis of the data yields slopes, intercepts, and correlation coefficients of these curves a.s given in Table 2. Similar data for batch calcined stucco are summarized in Table 3.

Table 9 Analysis of thick coatings (stucco) for EIFS in Germany (Lindner, 2000)...

The production of commercial building materials, e.g., portland cement and stucco, utilizes calcium sulfate in the form of the dihydrate or hemihydrate.f Gypsum is added in the production of portland cement to control set. Properties of cement can be adversely affected by the formation of hemihydrate during the grinding process. In the production of stucco, the hemihydrate is the preferred form. Consequently, investigators have adapted thermal analysis methods for estimating the quantities of each phase in these products. 

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