Читать книгу Monument Future - Siegfried Siegesmund - Страница 400

Because of the onsite observed weathering forms and the measured values of hydric dilatation, the two rock varieties were treated with a swelling inhibitor and then their hydric dilatation was measured again. After the treatment, the clastic material shows a plain reduction of the hydric dilalation of around 40 %. In the case of the RC variety, a reduction of the anisotropy of the hydric dilatation to nearly zero is remarkable (Fig. 5). Furthermore, the fine-grained material (RF) shows a reduction of more than 50 % (from 0.53 mm/m to 1.8 mm/m) in the Z direction (perpendicular to bedding), whereas the XY-direction shows a lower reduction reaching 0.093 mm/m.

During the consolidation test with the silica sol, gel formation sometimes occurs on the sample surface. This can also be attributed to the pretreatment with the swelling inhibitor. Silica sols are ion-sensitive and can therefore only be used to a very limited extent on saline substrates. And, a swelling inhibitor is actually a saline solution. Consolidation tests with the silica acid esther showed a lower consolidation effect, but also a low darkening of the sample material.

It is striking that there is only a very slight increase in strength, in the case of both consolidants to the two directions parallel to the stratification (XY) (Tab. 2). The increase is around 8 % for the RF by using KSE and 7.5 % using the silica sol. The 262RC variety reaches less than 1 % in the case of KSE and around 3 % for the silica sol. The strengthening effect perpendicular to the bedding (Z) is much higher for both rock types and consolidants (Tab. 2). This attains 16 % for the RF and 30 % for the RC variety by using KSE. By using the silica sol, a consolidation effect can be established in the Z-direction for RF with 19 % and for RC at 30 %.

Figure 4: Hydric dilatation of the two rock varieties.

Figure 5: Reduction of the hydric dilatation after the treatment with the swelling inhibitor.