Читать книгу Monument Future - Siegfried Siegesmund - Страница 398

The porosity of the basaltic building stones range between 17.4–23.5 % (Tab. 1). The rock material shows a very high porosity of 30 % (RC) to even 38.2 % for the RF variety (Tab. 1). The fine variety (RF) contains a microporosity (0.001–0.1 µm) of 10.2 %, whereas the RC variety contains 23.2 % microporosity (Fig. 2 below).

The saturation degree S of all investigated samples is high. The S-value of the RF variety is 0.94 and for the RC variety 0.97. The two basalt varieties show similar values: 0.97 for the basalt sample of the foundation and 0.95 for the sample from the wall.

Directional water uptake of the rock material, however, shows different values. Z means perpendicular to the bedding, X parallel to the bedding and Y parallel to the bedding and parallel to the lamination of the stone material. Water uptake for the clastic rock (RC) sample attains a value of around 11.8 kg/m²/√h in all directions. Much lower values 261were determined for the fine-grained variety (RF), which show values of 4.6 and 4.5 kg/m²/√h for the XY direction and 5.2 kg/m²/√h for the Z direction, thus attaining an anisotropy (A) of 13 %. This tendency could also be shown by the measurements of ultrasonic velocity, expecially in the case of the fine-grained rock variety (RF), (Tab. 2).

Table 1: Porosity and density of the investigated stone samples.

Sample	Porosity (%)	Density (g/cm3)	Matrix-density (g/cm3)
Basalt (BF)	17.4	2.3	2.78
Basalt (BW)	23.5	2.3	7.8
Rock (RF)	38.2	1.5	2.42
Rock (RC)	30	1.73	2.48

The rock material shows a different hydric dilatation. Both varieties show remarkable swelling, while the clastic material (RC) with up to 1.04 mm/m reaches high and critical values (Fig. 4). The fine-grained rock material (RF) only shows half of that dilatation, but a higher anisotropy of more than 50 % (Fig. 4).

Ultrasound velocity decreases in both rock varieties under water-saturated condition (Tab. 2). This particularly affects the RC variety with an average of 38 % and an average of only 7.5 % for the RF variety (Tab. 2).

Table 2: Ultrasonic velocity of the rock samples.

Sample	X (m/sec)	Y (m/sec)	Z (m/sec)	A (%)
RF dry	1,905	2,340	1,464	37.4
RF wet	1,791	2,110	1,366	35.2
RF KSE	2,200	2,377	1,692	23
RF sol	2,210	2,355	1,802	21.6
RC dry	1,570	1,544	1,250	20.3
RC wet	909	783	930	13.8
RC KSE	1,585	1,553	1,780	12.7
RC sol	1,593	1,610	1,795	11.3